Unit 2 Test Flashcards
1
Q
What are atoms made up of?
A
Subatomic particles
2
Q
What are the three types of subatomic particles?
A
protons, neutrons, electrons
3
Q
Where is the nucleus and what is it made up of?
A
Its in the center of an atom and made up of protons and neutrons, tightly packed together
4
Q
Where is the electron cloud?
A
On the outside of the nucleus
5
Q
What is the atomic number?
A
The same as the number of protons
6
Q
What do all atoms of the same element have in common?
A
They all have the same number of protons
7
Q
What is a proton’s charge and relative mass?
A
Positive and one
8
Q
What is the number of electrons in a neutral atom?
A
the number of protons
9
Q
What is a electron’s charge and relative mass?
A
negative and zero
10
Q
What is a neutron’s charge and relative mass?
A
No charge and one
11
Q
What do subscripts (in a chemical formula) represent?
A
The relative number of each type of atom
12
Q
Does a subscript come in before or after the element symbol?
A
After
13
Q
When are parenthesis used?
A
When a subscript effects a group of atoms
14
Q
Describe a solid (in terms of kinetic theory)
A
- fixed shape
- particles closely packed together
- particles held in one position and vibrate around
15
Q
Describe a liquid (in terms of kinetic theory)
A
- particles stay relatively close together
- particles can move around each other
16
Q
Describe a gas (in terms of kinetic theory)
A
- particles are far apart
- particles move rapidly and collide with each other and with the walls of the container
17
Q
What is the mass # (number)?
A
The sum of protons and neutrons in an atom
18
Q
What are isotopes?
A
atoms of the same element that have a different number of neutrons (sometimes isotopes are radioactive)
19
Q
What is atomic mass?
A
The weighted average of the masses of all the known isotopes of the element
20
Q
What is molar mass?
A
The mass of one mole of any element in grams (the same as atomic mass but with a unit)
21
Q
What is the only way to form a compound from elements?
A
A chemical reaction
22
Q
Does bond breaking require or release energy?
A
requires energy
23
Q
Does bond making require or release energy?
A
releases energy
24
Q
What is a solution?
A
a homogeneous mixture made up of very tiny particles (molecules, atoms, ions)
25
What is the solvent?
the substance that makes up the largest % of the solution
26
What is the most common/universal solvent?
water
27
What is the solute?
The substance being dissolved (in water, solutes are polar covalent comps. or ionic comps.)
28
What is a saturated solution?
a solution that has all the dissolved solute that it can hold (max solute)
29
How can you identify that a solution is saturated?
Adding more solute will result with undissolved solute particles at the bottom after mixing
30
What is an unsaturated solution?
A solution that can still hold more solute
31
What is filtrate?
The liquid that passes through the filter
32
What do you measure volume with?
graduated cylinder
33
What do you measure mass (g) with?
electronic balance
34
What do nuclear reactions change?
Nuclear reactions change the composition of an atom's nucleus
35
What do chemical reactions change?
Only the outer electrons (nucleus stays the same)
36
What does the stability of a nucleus depend on?
The ratio of protons to neutrons
37
What are radioisotopes?
radioactive isotopes that have unstable nuclei
38
What is Carbon-14
A radioisotope of carbon
39
What is radioactive decay?
when an unstable nucleus loses energy by spontaneously emitting radiation
40
Why is radiation called decay?
the original nucleus decomposes and forms a new nucleus (all while releasing radiation)
41
What are the three kind of radiation?
Alpha, beta, gamma
42
What is an alpha radiation?
- consist of 2 neutrons and 2 protons
- identical to helium-4
- do not have much penetrating power
43
What is beta radiation?
- when a neutron changes into a proton and electron (electron gets shot out of nucleus)
- 100 times more penetrating then alpha particles
44
What is gamma radiation?
- very energetic form of light (human eyes cannot see)
- accompanies alpha and beta radiation
- much more penetrating (only stopped by heavy shielding)
45
What is the symbol for gamma radiation?
Y
46
What is the unit for atomic mass?
amu
47
What are the indicators of a chemical reaction?
- emission of light or heat
- formation of gas
- formation of a precipitate (when a solid forms)
- color change
- emission of odor
48
What are the 2 parts of a chemical reaction?
- Reactants (substances you start with)
- Products (substances you end with)
49
What is a catalyst?
A substance that speeds up a reaction without being changed by the reaction
50
What's a biological/protein catalyst?
Enzymes
51
What are exothermic reactions?
- release energy (as heat)
- bonds formed
making substance cooler with potential energy
52
What are endothermic reactions?
- absorbs heat
- bonds broken
making substance warmer with kinetic energy
53
What are the 5 types of chemical reactions?
synthesis, decomposition, single replacement, double replacement, combustion
54
What are synthesis reactions?
- also known as combination reactions
- two elements or compounds are combined to make one compound (release energy - exothermic)
A+B ➝AB
55
What are decomposition reactions?
- breakdown of compounds into smaller compounds or element (uses energy - endothermic)
AB ➝A+B
56
What is single replacement?
- also known as single displacement
- one element replaces another (reactants an element and a compound, products dif. element and compound)
A+BC ➝AC+B
57
What is double replacement?
- two compounds replace each other (reactants iconic compounds or acid)
- usually in aqueous (aq) solution
AB+CD ➝AD+BC
58
What is combustion?
A reaction where compound reacts with oxygen (products always are C0₂ + H₂O)
59
What are the steps of recognizing the type of chemical equation?
60
What is matter?
anything that takes up space
61
What are the two types of matter?
pure substances and mixtures
62
What are the two types of pure substances?
compound (molecule) and element
63
What are the two types of mixtures?
Heterogeneous and Homogeneous (solution)
64
What are the two types of heterogeneous mixtures?
suspensions and colloids
65
Are solutions clear?
yes (a beam of light passing through them cannot be seen)
66
What does aqueous (aq) mean?
dissolved in water
67
What does solubility mean?
the measure of the amount of solute that can dissolve in a specific amount of solvent at a specific temperature and pressure
68
What is a solubility curve?
A curve that displays how much solute will dissolve in a given amount of solvent at a specific temperature
69
what is the solution equilibrium?
When the rate of undissolved solute coming in equals the rate of undissolved solute going out
70
What is a supersaturated solution?
when a solution contains greater than the max solute
71
How do you find how many significant figures there are?
When decimal point is present, count sig. digits starting with the first non-zero digit on the left.
When decimal point is absent, count sig. digits starting with the first non-zero on the right.
(present-left, absent-right)
72
What do you do when multiplying or dividing?
Round the answer to the least number of significant digits
73
What do you do when adding or subtracting?
Round the answer to the least number of decimal places
74
What is a counting?
A number with an exact value
75
What are quantities?
defined numbers like those in a measurement system
76
What is an estimated digit?
the last digit taken using a measurement device
77
How do we balance chemical equations?
we adjust the coefficients until the equation is balanced
*balance compounds before other elements and balance O and H last.
78
What does a triangle over the yield sign mean?
Heat
79
What does cat over the yield sign mean?
Catalyst
80
Are nuclear reactions affected by changes in temperature, pressure, or catalysts?
No
81
Can nuclear reactions be sped up, slowed down, or shut off?
No
82
What is radiation?
The penetrating rays and particles emitted by a radioactive source.
83
What two things does atomic mass represent?
1. The average mass of a single element in amu
2. the mass of one mole of atoms in grams
84
What is kinetic energy?
energy of movement (attractions between molecules, determines how freely they can move and whether they take the shape of a container or not)
85
Do liquids have fixed volume?
Yes
86
Do gasses have fixed volumes?
No
87
What is electrolysis?
Process where electrical energy is used to produce a chemical change
88
What is oxidation?
reduction caused by electrolysis oxidation taken away or added by electrical current
89
Who was John Dalton and what did he concur?
the father of modern chemistry
- believed that elements are composed of tiny particles called atoms and all atoms of one element are the same
90
What do protons define?
an elements identity
91
What do electrons (ions) define?
an elements chemical properties
92
Who discovered electrons?
TJ Thompson in 1897
93
What does MG stand for?
Magnesium
94
What does Li stand for?
Lithium
95
What does Ba stand for?
Barium
96
What does Ag stand for?
Silver
97
What does Na stand for?
Sodium
98
What does Au stand for?
Gold
99
What does Cu stand for?
Copper
100
What does F stand for?
Fluorine
101
What does As?
Arsenic
