MCAT Chemistry Flashcards
1
Q
Which particle is more massive: proton or neutron?
A
Neutron
2
Q
What is an element’s MASS NUMBER?
A
sum of the protons and neutrons
3
Q
What is the symbol, i.e. letter, for MASS #?
A
A
4
Q
what is an atomic mass unit? Specifically, what is its actual definition?
What is it’s numerical value?
A
Unit used to describe the mass of atoms, molecules, and particles. One amu is exactly one-twelfth the mass of a carbon-12 atom, which is ~ 1.66 x 10-24 grams (g)
[Kaplan mcat gen chem]
5
Q
what is the unit for atomic mass?
A
amu
6
Q
what is ‘atomic mass’?
A
mass of an atom compared to mass of carbon-12 atom
7
Q
What is ‘atomic weight’ or ‘molecular weight’?
A
weight, in grams, of 1 mole of an atom or molecule
[NOTE: Kaplan treats atomic mass & atomic weight as two different terms, while EK and college chem textbook uses them interchangeably]
8
Q
what is another name for an ‘a.m.u.’?
A
dalton
9
Q
What is the SI abbreviation for an amu?
A
u
10
Q
what is another name/term for atomic weight?
A
Molar mass
11
Q
What is a mole?
(What substance in nature is the mole based on?)
A
It’s the number of particles in a 12-gram sample of carbon-12.
12
Q
In a periodic table, which groups are called the “periods”? Are the columns referred to as periods, or are the horizontal rows referred to as periods?
A
Horizontal rows
13
Q
What is each vertical column in a periodic table called?
A
Each column called be called a ‘group’ or ‘family’
14
Q
What are the three main categories that all the elements can be grouped into?
A
Metals,
non-metals, and
metalloids
15
Q
What are metalloids?
A
Elements that share the characteristics of metals and nonmetals
16
Q
How many groups are there in the periodic table?
A
18
17
Q
What 4 characteristics of metals should u know for MCAT (according to EK)?
A
Metals are:
lustrous,
malleable,
ductile,
and thermally and electrically conductive
18
Q
What does ‘malleable’ mean?
A
Easily hammered into thin strips
19
Q
what does ductile mean?
A
Easily stretched, easily drawn into wires
20
Q
Which group are the alkali metals?
A
Group 1
21
Q
which group # are the alkaline earth metals?
A
2
22
Q
which group # are the halogens?
A
17
23
Q
in the periodic table, how is the atomic mass for element determined/derived?
A
The atomic mass for a given element in the table is actually the weighted average of all the naturally occurring isotopes of the element
24
Q
What are transition metals??
A
Groups 3-12 on the periodic table
25
What are chalcogens?
Group 6A (group 16) elements
26
what are the most famous of the chalcogens?
Oxygen and sulfur
27
which of the noble gases are *liquid at room temp*?
none
28
True/False:
## Footnote
the mnemonic I Brought Clothes From Old Navy Home refers to the halogens
False!
I, Br, Cl, F are halogens, but *O, N, and H* are *NOT* halogens! However, all of these are **diatomics**!
29
Do larger or smaller atoms make **stronger** *pi* bonds?
Smaller atoms (p. 5, EK Chem)
30
When transition metals form subshells, which subshell loses electrons first?
S subshell
31
After the s subshell of a transition metal loses electrons, which subshell loses electrons next?
D subshell
32
What law/equation do you use to find the force exerted by the nucleus on the outermost electron?
Coulomb’s law
33
How do you write **Coulomb’s law** as an equation?
F = _*k *\* q1 \* q2_
r2
34
Do ions with the *same exact # of electrons* have increasing or decreasing _radii_ **as the Z of the nuclei increase**?
***Decreasing* radius with *increasing* Z**, given that the *# of electrons stays the same* for all the elements being compared
35
What is Zeff?
Effective nuclear charge
36
What is effective nuclear charge?
the net positive charge experienced by an ***outer*** electron in a multi-electron atom.
37
What is the equation for Zeff?
**Zeff = Z − S**
## Footnote
where:
**Z** is the number of protons in the nucleus (**atomic number**)
**S** is the average number of electrons *between* the nucleus *and* the electron in question (the number of ***non*valence electrons**).
38
How do you use Zeff?
Plug in Zeff for one of the ***q*** values, rather than plugging in the actual # of protons
39
In the periodic table, Zeff **(increases/decreases)** going from *top to bottom* and **(increases/decreases)** going from *left to right.*
Increases,
increases
40
In the periodic table, Atomic radii **(increases/decreases)** going from top to bottom and **(increases/decreases)** going from left to right.
(p. 7, EK)
Increases,
decreases
41
what is the name given to the energy required to detach an electron from a *neutral* atom in the gaseous state?
Ionization energy
X **+** energy → X+ **+** e-
42
In the periodic table, *ionization energy* **(increases/decreases)** going from top to bottom and **(increases/decreases)** going from left to right.
Decreases, increases
43
What is electronegativity?
The tendency of an atom to attract an electron and thereby form a bond with another atom
44
What is the name given to the system that's used to measure **electronegativity**?
the Pauling scale
45
What is the highest electronegativity value?
4 (or sometimes 4.1)
46
which element(s) have the highest electronegativity?
F
47
What are the electronegativity values for the noble gases?
The noble gases have no electronegativity value
48
In the periodic table, *electron affinity* **(increases/decreases)** going from top to bottom and **(increases/decreases)** going from left to right.
decreases,
increases
49
How does ‘dipole moment’ relate to electronegativity?
The greater the difference in electronegativity between 2 bonded atoms, the greater the dipole moment
50
In the periodic table, *metallic* characteristics **(increases/decreases)** going from top to bottom and **(increases/decreases)** going from left to right.
increase,
decrease
51
What is a **dipole moment**?
Dipole moment is the **measured polarity of a *polar covalent*** bond.
Dipole moment refers to the quality of a system to behave like a dipole.
52
What is electron affinity?
X **+** e− → X− **+** energy
## Footnote
3 definitions:
1:
The energy released when an electron is **added** to a **NEUTRAL** atom that is in a **gaseous** state. *(EK chem)*
2:
EA is the amount of energy required to *detach* an electron from a ***singly charged negative** ion*;
An equivalent definition is the energy released when an electron is attached to a ***neutral*** atom or molecule. *(wiki)*
3:
EA is the energy change that occurs when an electron is added to a gaseous atom. **EA represents *the ease with which the atom can accept an electron*.** (suhail’s Kaplan p 25)
53
What is the relationship between Zeff and EA?
Direct relationship
54
In the periodic table, *electron affinity* **(increases/decreases)** going from top to bottom and **(increases/decreases)** going from left to right.
decreases,
increases
55
How many **base units** are there in the SI system?
7
56
list the 7 quantities being measured by the 7 base units of the SI system:
amount,
electric current,
length,
luminous intensity,
mass,
temperature,
time
57
What SI unit measures time?
second
58
which What SI unit measures temperature?
Kelvin
59
Which SI unit measures mass?
Kilogram
60
What SI unit measures luminous intensity?
Candela
61
What SI unit measures length?
meter
62
What SI unit measures electric current?
Ampere
63
What SI unit measures amount?
mole
64
What amount does the prefix *Mega-* denote?
106
65
What amount does the prefix *Kilo-* denote?
103
66
What amount does the prefix *Femto-* denote?
10-15
67
What amount does the prefix *nano-* denote?
10-9
68
What amount does the prefix *pico-* denote?
10-12
69
What amount does the prefix *Deci-* denote?
10-1
70
What amount does the prefix *Micro-* denote?
10-6
71
What amount does the prefix *Centi-* denote?
10-2
72
What amount does the prefix *Milli-* denote?
10-3
73
What is the difference between a **molecular formula** and an **empirical formula**?
Empirical formula only shows the **lowest ratios** **between** the atoms in the molecule;
molecular formula shows the **actual number of atoms** in the molecule
74
What’s up the suffixes *–ic* and *–ous* for Cations?
If an element can have more than one ionization state, the *-ic* was used for the cation with the **greater** positive charge, *-ous* for the cation with the **lesser **positive charge.
75
What’s up with the suffix *–ic* and *–ous* for Polyatomic Anions?
Polyatomic anions that come in multiple varieties are named depending on how many oxygens they have.
76
Which PAIs are named *–ate *and which are named *-ite*?
“*-ate*” is given to the PAI with more oxygens, *-ite* for the PAI with less
77
order the anion suffixes/prefixes from *least* oxygens to *most*:
per- , -ite, -ate, hypo-
hypo-ite,
- ite,
- ate,
per-ate
78
what is theoretical yield?
Amount of product made when a reaction runs to completion
79
what is the *percent yield* formula?
*Why* is the percent yield formula used?
In reality, a reaction may not run to completion before stopping. So the *actual* yield of a product will be less than the theoretical yield.
Formula for % yield is:
(actual yield/theoretical yield) \* 100 = % yield
80
What does it mean when the symbol delta (∆) is present above the reaction arrow in a reaction equation?
delta means that **heat is added** to rxn
81
what does it mean when you see a reaction equation with two parallel arrows pointing in opposite directions?
It means the rxn can reach equilibrium
82
What does it mean when you see this symbol ∩ in a reaction equation?
It represents **resonance structures**
83
What are the two basic types of solids?
Crystalline and amorphous
84
What’s the difference between a **crystalline** solid and an **amorphous** solid?
Crystalline solids have a **specific melting point**, and a well-ordered structure of **repeating units**. These *repeating units* can each be *atoms*, *molecules*, or *ions*.
Amorphous solid can melt over a temperature range and has no repeating molecular structure.
85
What are polymers?
Solids that **have repeating structural units** at the molecular level, *BUT* can be amorphous solids **or** crystalline solids.
86
what determines whether a polymer is made into an *amorphous* solid or a *crystalline* solid?
Usually, rapid cooling of liquid polymers results in amorphous solids, slow cooling results in crystalline solids
87
what are biological examples of polymers?
DNA,
glycogen,
protein
88
what is ‘bond length’?
average distance *between two* *nuclei* in a bond, at which distance the ***potential energy*** of the system will be the ***lowest*** (an equilibrium between the tug of war created by like and unlike electrical charges)
89
what are the 4 types of crystals?
Ionic,
network,
metallic, and
molecular
90
what are **network crystals**?
they consist of an infinite network of atoms,
held together by **polar and non**polar bonds.
They are made up of atoms **sharing their valence electrons**.
91
what are examples of a *network crystal*?
Diamond,
graphite,
swarovski glass crystal (_not_ like *regular* glass, which is also silicon dioxide but is an amorphous solid)
92
what are ionic crystals?
Solids that have *oppositely charged ions held together* by **electrostatic force**
93
what are metallic crystals?
**Single-element** metal solids that are held together by **delocalized** electrons
94
What are ‘molecular crystals’?
solids whose atoms/molecules are held together by **weak intermolecular** forces
95
molecular crystals are solids whose atoms/molecules are held together by *weak intermolecular forces*
what are the above weak intermolecular forces collectively called?
Van der Waals forces
96
What *kinds* of Van der Waals forces are there?
Hydrogen bonds,
dipole-dipole forces,
dispersion forces
(http://www.utas.edu.au/sciencelinks/chemincon/files/s1\_grow/s1\_soils/bonding/index.html#molecular)
97
In an atom, what is the *name of the number* assigned to each primary ‘energy level’ or ‘**shell**’ of electrons?
*Principal quantum* number
98
What is the symbol for the **principal quantum #**?
n
99
what is the symbol for the *azimuthal* quantum number?
ℓ
## Footnote
(lower case L)
100
which LETTER is assigned to label the *first* shell, or *first* energy level?
K
101
What are the letters that follow K?
I.e., what are the letters assigned to the **2nd, 3rd, 4th** shells?
L, M, N
102
What is the overall term/name of the mini-levels *within* each shell?
Subshell or
sublevel
103
what is the term/name of the number assigned to each subshell?
Azimuthal quantum number
104
how many *subshells* or *sublevels* exist for the known atoms/elements?
4
105
what are the names/terms (letters) assigned to these subshells or sublevels?
s
p
d
f
106
What is the formula that tells you the MAXimum # of electrons that can fill a given **shell**/energy level?
2n2
107
What is the equation that tells you the relationship between azimuthal quantum number and principal quantum number?
ℓ = n - 1
108
what is the name of an area within the atom where an electron can *probably* be found?
orbital
109
what is the relationship between an **orbital** and a **sublevel**?
Orbital is the subdivision of a sublevel
110
What is the Heisenberg principle?
It is impossible to know both the **position** and **momentum** of an electron *at the same time*
111
how many electrons does an orbital hold?
2
112
what is the Magnetic quantum number?
name of the number assigned to an **orbital**
113
what is the number assigned to *each* individual **electron** in an atom?
Electron spin quantum number
114
what is the symbol for an electron spin quantum number?
ms
115
What is the Pauli exclusion principle?
no two electrons can have the same four quantum numbers
116
what are the possible electron spin quantum numbers?
1/2
and
-½
117
what is the Aufbau principle?
A lower-energy subshell is **completely filled**, *before* electrons are placed in the next, higher subshell.
118
What is **Hund**’s rule?
In the same subshell, Electrons will not *completely* fill any orbital until:
1: All the orbitals within that subshell contain **at least one** electron, AND
2: the **un**paired electrons in the subshell have **parallel spins**
119
when talking about electron spins, what does it mean to say that 2 electrons have *‘parallel’ spins*?
They have the **same spin** (such as ½ and ½, or -1/2 and -1/2)
120
Why do electrons follow Hund’s rule? Why do electrons prefer empty orbitals to half-filled orbitals? (Kaplan gen chem. Page 30)
Because a mutual repulsion must be overcome for 2 electrons with like charges to exist in the same orbital.
121
What was Planck’s quantum theory?
EM energy is **quantized**/discontinuous.
EM energy comes in **discrete bundles / units / packets** that are *related to the **frequency*** of the EM wave.
122
How is Planck’s quantum theory explained in equation form?
E = hf
123
What is de Broglie’s formula?
λ = h/mv
124
what did de Broglie’s equation show?
Electrons and other *moving masses* exhibit ***wave characteristics***
125
what phenomenon in nature showed us that light is made up of photons?
The photoelectric effect
126
who’s famous for **the photoelectric effect**?
Einstein
127
specifically, *how* was the photoelectric effect observed? *What specific phenomenon* was used by Einstein to demonstrate the photoelectric effect?
Light shining on a metal causes the emission of electrons
128
how does the photoelectric effect demonstrate the quantized nature of EM?
Einstein showed that light is made up of particles
129
with regards to the photoelectric effect, what is the ‘work function’?
the work function of a metal is the minimum amount of energy required for the metal to eject an electron when it is hit by a photon
130
what is the symbol for the **work function**?
Φ
131
In the Photoelectric effect, what formula shows us the KE of the ejected electron?
KE = hf - Φ
132
what is **hf** in the work function formula?
The **KE of the photon** that ejected the electron
133
what are the exact values for temp and pressure at STP?
0 deg Celsius,
1 atm
134
at STP, what is the avg distance between gas molecules? (EK, p 23)
35 angstrom
135
what is the mean free path?
Distance traveled by a gas molecule between collisions
136
what is the **mean free path** of oxygen at STP?
1600 angstrom
137
can a *nonpolar* gas and a *polar* gas mix homogeneously?
YES
Gas can mix regardless of polarity differences
138
can gases of different densities possibly separate according to their density? [WITHOUT centrifuges]
**If temp is low enough,** gravity can cause denser (colder) gases to settle beneath less dense gases
139
what is the name of the concept/theory that relates to ideal gases?
Kinetic Molecular Theory of Gases
140
describe an ‘ideal gas’ as put forward by the Kinetic Molecular Theory.
(hint: there are 4 characteristics)
(p. 24, EK chem)
gas molecules have **zero volume**;
gas molecules exert **no** forces of **attraction or repulsion** towards each other;
gas molecules make **completely elastic collisions** with each other and their container, thus neither gaining nor losing any energy;
the **avg kinetic energy** of gas molecules is **directly proportional to** the **temperature** of the gas.
141
what is the ideal gas law? Give the equation.
PV = nRT
142
What is **P** in the equation for ideal gas law?
Pressure
143
what is the unit for P (ideal gas law)?
atm
144
What is the **V** in the ideal gas law equation?
Give the **unit**, too.
Volume,
in Liters
145
what is n, in the ideal gas law eqn?
of moles of gas
146
what is **T**, in the ideal gas eqn?
give the **unit**.
Temperature in Kelvin
147
what is **R** in the ideal gas eqn? give the **unit**
the universal gas constant
(0. 08206 L\*atm\*K-1\*mol-1 or
8. 314 J\*K-1\*mol-1)
148
what is the meaning of the term ‘standard molar volume’?
the volume that all gases will have **at STP**, ***IF ...***
they are acting as IDEAL gases
149
All gases will have the same volume, if they have the same \_\_\_\_\_\_, \_\_\_\_\_\_, and \_\_\_\_\_\_\_.
temperature,
pressure, and
of molecules
150
What does Charles’ law state?
**Volume** of a gas is proportional to **temperature**,
at *constant* pressure
151
What does Boyle’s law state?
**Volume** of a gas is ***inversely*** proportional to **pressure** at _constant_ temperature
152
what's Avogadro’s law?
**Volume** of a gas is proportional to the **# of moles** at _constant temp and pressure_
153
What conditions do you need to get a *real* gas to act more like an ideal gas?
Gases under **lower pressure** and **higher temperatures** behave more ideally than gases with higher pressures and lower temps
154
According to the kinetic molecular theory, the kinetic energy of a gas molecule **(increases/decreases)** proportionally with temp?
increases
155
are **ionic solids** electrically conductive?
No,
## Footnote
but they *can* conduct if they are in **aqueous solution** or if they are **molten**
156
What unit of measurement is derived from Newton per square meter. (kg/m\*s^2)
[wikipedia]
pascal
157
what is the short form (symbol**/**abbreviation) for the pascal?
Pa
158
how many **pascals** is equal to 1 **atm**?
101,325 Pa or
101.325 kPa
159
how many mmHg do you need to equal 1 atm?
760 mmHg
160
what is another unit that equals mmHg, so that every numerical value for **mmHg** is equal in the other unit?
torr
161
Do **alkaline earth** metals generally have high or low **electron affinities**?
low
162
what scale is used to measure electronegativity?
Pauling scale
163
what element is the *least* electronegative?
Cesium
164
what is the *highest* electronegativity value?
4.0, (some sources say 4.1)
165
the characteristic of electronegativity is related to what other periodic trend/characteristic?
ionization energy
166
metals generally have **[high/low]** melting points
high
167
transition metals have **[high/low]** melting points and **[high/low]** boiling points
high melting,
high boiling
168
how hard/soft are transition metals?
very hard
169
ionic compounds have **[high/low]** melting points and **[high/low]** boiling points.
high
high
170
What is the number of protons and neutrons in an element called?
Mass number
171
what is the most common carbon **isotope**?
carbon-12
172
what is ‘atomic mass’?
mass of an atom *compared to* mass of carbon-**12** atom
173
what *percentage* of all carbon found in nature is carbon-**12**?
99
174
When describing the properties of an element, what does the symbol Z represent?
Atomic number
175
what is the unit for atomic **weight**?
g/mol
176
what is another name for a dalton?
amu
177
What does the abbreviation ‘u’ represent?
It’s the same thing as ‘amu’ (dalton)
178
what does **molar mass** mean?
It’s another name/term for **atomic weight.**
179
What is the *term* for the number of atoms in a 12-gram sample of carbon-12?
Mole
180
# fill out this conversion:
\_\_\_\_\_\_\_\_ amu = 1 gram
6.02 x 1023 amu = 1 g
181
what is each *horizontal* row in a periodic table called?
Period
182
what is the term used to describe a metal as being easily stretchable?
ductile
183
what is the term used to describe a metal as being easily hammered into thin sheets?
Malleable
184
What are halogens?
group 17 elements
185
What does the mnemonic I Brought Clothes From Old Navy Home refer to?
The elements that appear as **diatomic** molecules in their *pure element form*
186
What’s another name/term for Group **16** elements, which includes oxygen?
chalcogens
187
which of the noble gases are solid at room temp?
none
188
What is the use of Coulomb’s law in chemistry?
You use it to find the force exerted by a nucleus on the outermost electron
189
What is the symbol for effective nuclear charge?
Zeff
190
What is ionization energy?
the name given to the energy required to detach an electron from an atom in the gaseous state
191
with *increasing* Zeff, it becomes **[easier/tougher]** to knock off an electron (i.e., ionize).
tougher
192
The tendency of an atom to attract an electron and thereby form a bond with another atom is called \_\_\_\_\_\_.
electronegativity
193
What is the Pauling scale?
The most commonly used measurement of electronegativity
194
Which element(s) have *undefined* electronegativity?
noble gases
195
What prefix denotes 10-15?
femto-
196
What prefix denotes 10-9?
nano-
197
What prefix denotes trillionTH?
pico-
198
What prefix denotes tenth?
deci-
199
What prefix denotes 103??
kilo-
200
What symbol represents resonance structures when you see that symbol in a reaction equation?
∩
201
are **all** the electrons of a solid metal floating around?
NO.
only **valence** shell electrons
202
what kind of crystal is unlike metal solids (‘metal crystals’) , ionic solids, and network covalent crystals/solids?
Molecular crystals
203
what bond holds together ionic crystals?
Ionic bond
204
what bond holds together a solid piece of metal?
Metallic ‘bond’
205
what bond holds together a covalent network solid?
covalent
206
what bond holds together molecular crystals?
Van der Waals forces
207
what is the azimuthal quantum number?
Number assigned to each **subshell**/sublevel of electrons surrounding an atom
208
what is a ‘principal quantum number’?
the number assigned to each main ‘level’ or ‘shell’ of electrons surrounding an atom
209
what is each sublevel broken up into?
orbitals
210
what is the definition of ‘orbital’?
An area within an atom where electrons can **probably** be found
211
what is the term/name for the # assigned to each **orbital**?
Magnetic quantum number
212
what is the symbol for magnetic quantum number?
mℓ
213
How many orbitals does the s-sublevel have?
1
214
how many orbitals does the p-sublevel have?
3
215
what is the electron spin quantum number?
Number assigned to each electron in an atom
216
what scientific rule/law says that no 2 electrons in a given atom can have the same 4 quantum numbers?
Pauli exclusion principle
217
identify this quantum number:
-1/2
electron spin quantum number
218
identify this quantum number:
-2
magnetic quantum number
219
according to the Heisenberg uncertainty principle, what two characteristics of a particle cannot be known simultaneously?
Position, and momentum
220
what is the value of Planck’s constant?
6.63 x 10-34 J\*s
221
what is the symbol for planck’s constant?
h
222
what is the name of the rule that states that when building up an atom’s electron configuration, electrons are placed in orbitals, subshells, and shells in order of increasing energy?
Aufbau principle
223
what formula do you use to find the energy of a single photon?
(p 19, EK gen chem)
E = hf
224
what is noteworthy about the atomic masses listed on the Periodic Table for each element?
The atomic mass/weight listed for each element is actually a *WEIGHTED AVERAGE* of the masses of the *isotopes* that are found in nature
225
what does the formula 2n2 tell you?
The **max**imum number of electrons that can be found in energy level ‘n’
226
what are the “main group elements”?
the elements that are ***not* transition metals**.
Main group elements are found in group **1, 2, 13-18**
227
what is the term for the Distance traveled by a gas molecule between collisions?
Mean free path
228
All gases will have the same \_\_\_\_\_\_\_\_, if they have the same temperature, pressure, and # of molecules
volume
229
what is the universal gas constant? Give # and units:
0.08206 L\*atm\*K-1\*mol-1
or
8.314 J\*K-1\*mol-1
230
what is PV = nRT? What is this equation named?
ideal gas law
231
what is the pascal? Define it.
An SI-derived unit of **pressure**/stress.
It is a measure of **force per unit area**.
232
what are the units for the pascal?
The units are **Newton per square meter**.
(kg/m\*s^2)
233
what is another unit that equals **torr**, so that every numerical value for torr is equal in the other unit?
mmHG
234
What is the law/rule that electrons will not fill any orbital in the same subshell until all orbitals in that subshell contain at least one electron, AND the unpaired electrons in the subshell have parallel spins?
Hund's rule
235
What does ‘standard conditions’ mean?
For laboratory/chemistry purposes, it means
~ **1 atm**, and
25 degrees Celsius (= **298 K**) and
**1.00 molar** concentration for all soluble compounds
[Kaplan, and back of barron’s ap chem. book]
236
what is another way of saying ‘standard conditions’?
standard state
237
What is the name of the model of the atom that consists of electrons in circular orbits around the nucleus?
Bohr model
238
Do halogens generally have high or low **electron affinities**?
high
239
What does the Pauling scale measure?
Electronegativity
240
Name the **metalloids**.
Boron,
silicon,
germanium,
arsenic,
antimony, and
tellurium
(suhail’s Kaplan p 27)
241
How many valence electrons do the halogen elements have?
7
242
network crystals are AKA?
network covalent crystals
AKA
covalent network solids
243
\_\_\_\_ compounds do Not contain molecules.
All of the following are correct:
## Footnote
--**Ionic**
--**Network covalent**
--**Metallic**
244
What formula gives the total **Kinetic** Energy of *n* moles of gas?
(3/2)\*nRT
245
How is the speed of a gas related to its temperature?
The speed of a gas is proportional to the **square root of its temperature**.
246
How does the weight of a gas molecule relate to its speed?
the Velocity of a gas is **inversely** proportional to the **square root** of it's **Atomic mass**.
247
The universal gas constant (**R**) is a product of these 2 constants:
Boltzmann's constant, and
Avogadro's number
248
Given a **rate law** for a reaction,
(e.g., Rate = k [A]2 [B]4)
what is the Order of the reaction?
Add the exponents.
2 + 4 = **6**
249
T/F:
## Footnote
The **rate constant** (k) of a reaction depends on the concentration of the reactants.
Fals
250
T/F:
## Footnote
The **rate constant** (k) of a reaction depends on the Temperature.
tru
251
T/F:
A catalyst does not alter the **rate law** of a reaction.
fals
252
T/F:
A catalyst alters the rate **constant** (k) of a reaction.
tru
253
Rate = k [A]2 [B]4
## Footnote
What is the above called? What is it an example of?
it's a **rate law**
254
**Name** the equation that mathematically expresses the **rate constant** of a reaction.
Arrhenius equation
255
T/F:
## Footnote
**Equilibrium constant** is the same thing as **rate constant**.
FALS.
## Footnote
Equilibrium constant is **Keq** found in *mass-action* expressions.
Rate constant is the ***k*** found in *rate law*s.
256
What is the relationship between **temperature** and **Keq**?
The **Keq** for a given reaction is constant at a given specific temperature.
257
A **negative Keq** value tells you that the reaction favors:
reactants
258
A **positive Keq** value tells you that the reaction favors:
products
259
If a **Keq** value is **1**, then the reaction favors:
the reaction *balances* products and reactants. So neither side is "favored"
260
How is the Rate law of a reaction related to it's equilibrium and Keq?
Rate law, and Keq are ***not*** related.
261
(1) What is **Q**?
(2) How does Q relate to **Keq**?
(1) Q is the **ratio** of products to reactants (with each one raised to an exponent = to it's coefficient in the reaction equation). To put it more simply:
(2) Q is simply the Keq when the reaction is **not at equilibrium. **When the Q = Keq, then the reaction is at Equilibrium.
262
What does it mean, if Q is **less** than Keq?
reaction proceeds **forward**
263
What does it mean, if Q is **more** than Keq?
Reaction proceeds in the **reverse** direction.
264
T/F:
## Footnote
Changing the volume of a reaction container will affect the equilibrium.
***Partially*** true.
## Footnote
This is true ONLY for reactions involving gases.
265
T/F:
## Footnote
Adding an inert (noble) gas to a reaction container *will change* the equilibrium, since it affects the volume.
Fals.
## Footnote
Inert gases do not react. And the volume (of the container) is not changed.
Thus, equilibrium is unaffected.
266
A **[#]**-order chemical reaction follows the same trend as a half-life reaction.
FIRST
267
The half-life of a ***[#]***-order chemical reaction is **IN**dependent of the starting concentration of the reactant.
FIRST
268
The half-life of a *first*-order chemical reaction is **[dependent / INdependent]** of the starting concentration of the reactant.
independent
269
T/F:
A first-order (elementary) reaction is unimolecular.
tru
270
A *first*-order (elementary) reaction is **[unimolecular / bimolecular]**.
uni
271
A *second*-order (elementary) reaction is **[unimolecular / bimolecular]**.
bi
272
T/F:
## Footnote
A *second*-order (elementary) reaction is unimolecular.
fals.
second-order is **bi**molecular.
273
When the concentration of reactants are doubled, the rate of a first-order (elementary) reaction is **[unchanged / halved / doubled / quadrupled]**.
doubled
274
When the concentration of reactants are doubled, the rate of a second-order (elementary) reaction is **[unchanged / halved / doubled / quadrupled]**.
quadrupled
275
What's the difference between an **intermediate** versus an **activated complex**?
An **intermediate** is formed during a ***multi-step*** reaction, where it is the product of one of the steps and will become a reactant in another of the steps.
An **activated complex** is formed the middle of a (single step) reaction when the reaction's energy is near it's Ea ("activation energy").
276
In an **isolated** system, what can be exchanged between the system and its surroundings?
Nothing!
neither matter, nor energy
277
In an **closed** system, what can be exchanged between the system and its surroundings?
ONLY energy
278
If a person pushes down on a piston, the gas inside the leak-free tube is compressed.
This is an example of a/n **[open / closed / isolated]** system.
closed
279
What is convection?
transfer of heat energy thru a fluid (liquid, gas)
280
The 2 very best insulators are:
vacuum
and
air
281
What are **state functions**?
a *measurable* property, of a system, that depends only on the *current* state of the system, not on the way in which the system acquired that state (i.e., independent of time, history, or path)
282
Which of these properties of a gas is/are **state functions**?
* temperature
* heat
* work
temperature only
283
What is a **black body radiator**?
an idealized physical body that **absorbs** ALL incoming EMR
284
A black body can radiate/emit EMR if:
if the black body is at thermal equilibrium (i.e., at constant temperature)
285
Nothing can be exchanged between a/n **[open / closed / isolated] **system and its surroundings.
isolated
286
What is the FIRST Law of Thermodynamics?
The 1st law of conservation of energy states that the **total energy **of an ***isolated*** system is **constant**; energy can be transformed from one form to another, but **cannot be created or destroyed.**
287
What is the SECOND Law of Thermodynamics?
the **entropy** of an ***isolated*** system **never decreases**.
* Another way of saying it: *Isolated systems move towards **maximum entropy**.
* Another way of saying it:* If no energy enters or leaves a system, then the **potential energy** of the state will always be less than that of the initial state. AKA, ***entropy** happens*.
288
What is the THIRD law of Thermodynamics?
It's **impossible** for any process, no matter how idealized, **to reduce the entropy** of a system to **absolute-zero**
289
The 3rd Law of Thermodynamics is **AKA**:
Nernst's theorem, or
Nernst's postulate
290
What is the *mathematical expression* for **enthalpy**?
enthalpy = **U + P\*V**
## Footnote
where:
U = internal energy
P = pressure
V = volume
291
What does the superscript **º** indicate, in : Δ Hfº
All reactants and products are at **1 atm**
292
What is the **entropy** of a substance at Zero degrees Kelvin?
zero entropy
293
q **/** T = **????**
**Δ S** = heat / Temperature
(**Δ S** means "*change in **entropy***")
294
**Δ G** is spontaneous only if _______ remain(s) constant.
Pressure
&
Temperature
295
T/F:
A spontaneous rxn can**not** be **endo**thermic.
Fals
296
Under a spontaneous rxn, the free energy (Δ G) of the *universe* **[**increases **/** decreases**]**.
↓↓↓
297
For a rxn to be spontaneous, the entropy of the Universe must:
↑↑↑
increase
298
A reaction is spontaneous at all temperatures. This reaction is **[endot**hermic **/ exo**thermic**]** and **[**increases **/** decreases**]** the entropy of the *system*.
e**x**o-
and
**↑↑↑**
299
What effect do **catalysts** have on the **spontaneity** of the reaction?
no effect
300
If a reaction is *at equilibrium*, then that reaction's Δ **G** is **[** positive **/** negative **/** zero **]**.
zero
301
What's a **mole fraction**?
the amount of a **constituent** (expressed in moles), divided by the **total** amount of **all** constituents, **in a mixture**
302
For *ideally* dilute solutions, the **mole fraction** of the ***solvent*** is:
close to 1
303
Ideal solutions obey _____ Law.
Raoult's Law
304
A collistion between 2 objects is **elastic**, if:
the **Kinetic** Energy ***before*** the collision, is **the same as** the K.E. *after* the collision.
305
A ______ collision between 2 objects has a different final Kinetic Energy than the initial K.E. of the objects.
**_in_**elastic
306
Can **dialysis** extract colloidal particles?
Yep
307
Can simple **filtration** extract colloidal particles?
Nope
308
What is the **Tyndall Effect**?
When a beam of light passing through a **colloid** is **dispersed**, so that the beam becomes **visible from the side** (i.e., viewed perpendicular to path of beam).
309
What's the observed *difference* between light passing through a **colloidal** suspension, versus through a true **solution**?
Light passing through a *true solution* is not dispersed, so it can**_not_** be seen _from the sides_.
Light passing through a *colloidal* suspension can be seen from the sides.
310
(1) Can a colloid be extracted from suspension by addition of electrolyte?
(2) Why, or why Not?
Adding heat, or electrolytes, causes colloid particles to bind together, allowing them to be pulled down by gravity.
311
T/F:
## Footnote
If a compound/molecule is *very soluble* in H20, then it must be a *strong* electrolyte.
Fals.
## Footnote
Vinegar, for example, is a weak electrolyte but is very soluble in water.
312
Define **mole fraction**.
Mole fraction of a solution is:
of mol of *solute*, divided by # of mol of *solution*.
313
Define **parts per million**.
grams of solute / grams of solution
314
Define **heat of hydration**.
Enthalpy change when gaseous solute is dissolved in liquid.
315
A solid sublimates when the _____ of that solid is greater than the \_\_\_\_\_\_.
vapor pressure;
the partial pressure of the vapors above that solid.
316
Evaporation and Boiling are different. Evaporation occurs when the _____ of the liquid is greater than the \_\_\_\_.
vapor pressure;
partial pressure of the vapors already above the liquid.
317
Boiling occurs when the ______ of the liquid is greater than the \_\_\_\_\_\_\_.
vapor pressure;
total pressure of the gas above it.
318
An object's vapor pressure decreases if _______ also decreases.
temperature.
319
Condensation of a (gaseous) substance occurs when the _____ is greater than, or equal to, \_\_\_\_\_\_.
**partial pressure** of that substance's gas particles is greater than or equal to the **vapor pressure**.
320
**List** the **colligative properties** of solutions:
* vapor pressure
* boiling point
* melting point
* osmotic pressure
321
According to Raoult's law, ***actual*** vapor pressure is the product of:
*actual* vapor pressure of solvent = **(Vapor pressure of *pure* solvent) \* (mole fraction of solvent)**
322
Define "steam".
Water vapor above 100 degrees Celcius
323
A *non*-volatile solute is a solute that \_\_\_\_\_\_.
has No vapor pressure.
324
As **atmospheric** pressure **↑↑**, **vapor pressure** [increases / decreases / is Not changed].
does Not change
325
Which **Groups** on the periodic table are *readily soluble* in Water?
Halogens,
Alkali metals
326
Is **ammonia** soluble in Water?
Yep
327
Does the solubility product (**Ksp**) of a compound change, if the **pH** of the solution changes?
Nop. ***Ksp** only changes with **Temperature***.
328
What is the *trick* to guesstimate the **solubility** of a compound, using that compound's *solubility product* (**Ksp**)?
Guesstimating SOLUBILITY:
IF the compound dissociates into **2** particles, *solubility* is ≈ the **SQUARE ROOT of the** compound's **Ksp**.
IF a compound dissociates into 3 particles, then the solubility ≈ the **CUBE ROOT of the Ksp**.
***TRICK:***
**Divide the exponent** on the **Ksp** by **2** for the *two-particle* compounds;
**Divide the exponent** on the Ksp **by 3** for *three*-particle compounds.
329
When you write the Ksp for a given dissolved substance, what part of the sol'n is not included in the Ksp "expression"?
( "expression" → **Ksp** = **[]**\***[]** )
Pure liquids; and
pure solids
330
What is a "**saturated sol'n**"?
2 definitions:
1. sol'n that is **in equilibrium w/** its **precipitate**
2. sol'n whose **ion-product** (i.e., **[]**\***[]** ) is **equal to Ksp**
331
If Metal A and a different Metal B are given the same amount of heat, but Metal A's Temperature rises more quickly:
Which metal has the higher *specific heat*?
Metal **B**
332
In the formula **q = mCΔT**, "**c**" stands for:
the **specific heat** of a given substance
333
What is the **specific heat of H2O**?
1 cal / (g \* ºC)
or
1 cal / (g \* K)
or
1 J / (mol \* K)
334
T/F:
The heat capacity of an object increases with its size.
tru
335
The energy transfer ("**q**") is rougly = **ΔH** if there is:
constant pressure
| (like in a coffe-cup calorimeter)
336
* Bomb calorimeters measure \_\_\_\_\_\_.
* Coffee cup calorimeters measure \_\_\_\_\_\_.
Energy
Enthalpy
337
In a coffee-cup calorimeter, _____ is held constant.
pressure
338
What is the Heat of Fusion of Water? (give the numerical value)
80 cal/g
339
What is the difference between the **phase diagram** for the H2O versus the phase diagram for most other solutions?
In the phase diagram of Water, the solid-liquid boundary line has a **NEGATIVE slope**.
(which is why ice skating is possible - see PR Hyperlearning Review p. 377)
340
On a **phase diagram**, what is the **critical point**?
The **temperature *and* pressure**, beyond which a substance will become a **supercritical fluid**.
341
What's a **supercritical fluid**?
a substance that displays the **properties of *both* a gas and a liquid.**
342
What is the "heat of formation"?
the amount of energy required to make **one mole** of a compound **from pure elements** in their **natural** or **standard state**.
343
When talking about a **phase diagram**, what is the **critical temperature**?
the Temperature, above which **no liquid** will form, regardless of how high the pressure is
344
What are the **labels** for the axes (x-axis and y-axis) of a **phase diagram**?
Y-axis: Pressure
X-axis: Temperature
345
Is **supercritical fluid** the same thing as **plasma**?
no
346
Henry's Law is about:
the solubility of gases in liquids
347
What is the equation for **Raoult's Law**?
***actual* vapor pressure** of a solvent =
(**vapor pressure of solvent** when it's unadulterated and all by itself) **\*** (**mole fraction of solvent** in sol'n)
348
Define **vapor pressure**.
the pressure exerted, by the gaseous particles of a liquid which evaporated from the exposed surface of the liquid, on the liquid
349
When talking about liquids, what is a **volatile liquid**?
Liquids which **easily vaporize**, and thus have a **high vapor pressure**
350
What is the formula/equation for calculating **osmotic pressure**?
π = iMRT
351
1. What is the SYMBOL for **osmotic pressure**?
2. What is the UNIT for osmotic pressure?
1. π
2. **atm** (atmospheres)
352
In a copper-zinc galvanic cell, electrons flow from the Anode in the _____ sulface solution, to the Cathode in the _____ sulfate solution.
1. zinc
2. copper
353
Cations in the salt bridge of a galvanic cell move from the negatively charged _____ side to the positively charged _____ side.
1. cathode
2. anode
354
The **emf** of a galvanic cell depends on all the following:
1. **temperature** of the solution
2. **concentration** of the solution
3. **reactions** in the solution
355
In a galvanic cell, **reduction** occurs at the **[**anode **/** cathode**]**.
cathode
356
How soluble, in water, are **salts of sodium**?
*All* Na salts are soluble in water
357
How soluble, in water, are **nitrates**?
*all* nitrates are water-soluble
358
All compounds which contain these (monoatomic and polyatomic) **ions**, are water-**soluble**:
Li+,
Na+,
K+,
NO3 _,
C2H3O2 _,
ClO3 _,
ClO4 _
359
Are compounds containing **halide** anions, soluble or insoluble?
Compounds containing **Cl-**, **Br-**, and **I-** are soluble, except when these ions pair with Ag+, Hg22+, or Pb2+
360
Compounds containing Cl-, Br-, and I- are soluble, *except* when these ions pair with **[these ions]**.
Compounds containing Cl-, Br-, and I- are soluble, except when these ions pair with **Ag+**, **Hg22+**, or **Pb2+**
361
Which compound(s) are regarded as **slightly soluble**, rather than insoluble or soluble?
* calcium* hydroxide,
* barium* hydroxide,
* strontium* hydroxide
362
Compounds containing the **sulfate anion** are **[soluble/insoluble/slightly soluble]**.
Soluble, *except*
## Footnote
when sulfate bonds to **Sr**, **Ba**, **Pb**, **Ag**, or **Ca**.
363
Compounds containing the **hydroxide **anion are **[soluble/insoluble/slightly soluble]**.
**In**soluble, *except*
## Footnote
when bonded to **Li**, **Na**, **K**, **NH4+**.
**\*\*\*** When bonded to these cations, the hydroxide-containing compounds become ***slightly*** soluble: **Ca**, **Sr**, or **Ba**.
364
Are compounds containing the **S2-** anion soluble, insoluble, or slightly soluble?
**Sulfides** are **in**soluble, *except*
## Footnote
when containing Li, Na, K, NH4+, Ca, Sr, or Ba.
365
Compounds containing the **carbonate** anion are **[soluble/insoluble/slightly soluble]**.
**in**soluble, except
## Footnote
when bonded to Li, Na, K, or NH4.
366
Compounds containing the **phosphate** anion are **[soluble/insoluble/slightly soluble]**.
**in**soluble, except
## Footnote
when bonded to Li, Na, K, or NH4.
367
In a galvanic cell, oxidation occurs at the **[**anode **/ **cathode**]**.
anode
368
T/F:
## Footnote
A catalyst can ↑↑ the *total amount* of a product that is produced
fals.
## Footnote
Catalyst can ↑↑ the **RATE** of a rxn; it *cannot* change the **final amount** of product that is made
369
What is the **azimuthal quantum number** (ℓ) for the *s* sublevel?
0
370
What is another name/term for *azimuthal quantum number* (ℓ) ?
angular momentum quantum number
371
*Decreasing* the **diameter** of the metal wire used in a circuit, will **[**increase **/** decrease**]** the **resistance**.
↑↑
372
What is **specific gravity**?
density of ***something *÷** density of ***water***
373
Formula for **Buoyant Force** =
= (density **of fluid**) **\*** (g) **\*** (Volume that is submerged in water)
= [(density of water) ÷ (density of object)] \* weight
