To Study Flashcards
Dalton’s model
-3 main conclusions
- elements are made of atoms
- atoms of an element are the same
- compounds are formed by combining atoms
Rutherford Experiment:
-what was involved?
-3 main conclusions
Involved bombarding gold foil with alpha particles. when some went through foil but others bounced off nucleus, discovered that…
- atoms are mostly empty space
- nucleus is positively charged
- nucleus is DENSE
Bohr model
-3 main conclusions
- electrons surround nucleus in ORBITS. farther from nucleus=more energy
- energy is ABSORBED when electrons to move to outer orbits energy
- energy is RELEASED (light) when electrons move back to ground state
3a. the light released is used to identify the element
Wave-mechanical model (modern)
- nucleus is small, dense, positively charged
- electron cloud surrounds nucleus
- orbitals are areas where an electron is LIKELY to be found
Charge and mass of proton neutron and electron
Proton:
1 amu
+1
Neutron:
1 amu
0
Electron:
0 amu
-1
An unstable nucleus means…
- ratio of protons to neutrons is not 1:1
- irregular ratio means not effective at holding nucleus together, becoming susceptible to radioactive decay: they will spontaneously decay and emit radiation
Nuclear fission and fusion
Fission: larger atom splits into 2 or more smaller, neutrons and energy are byproducts
*generates radioactive nuclear waste
Fusion: smaller atoms combine into one larger atom, energy is byproduct
Forms of spontaneous transmutation/natural decay
alpha and beta decay
What is ionizing and penetrating power? Which forms of decay have the highest and lowest of each?
Ionizing is the ability to damage molecules and DNA.
Highest: alpha
Lowest: Gamma
Penetrating is the ability to break through barriers.
Highest: gamma
Lowest: alpha
What are the results of gamma, alpha, and beta (minus and pos.) decay?
Alpha: mass decreases 4, atomic number decreases 2
Beta minus: atomic number increases 1
Beta pos: atomic number decreases 1
Gamma: everything stays the same, energy is emitted (photon)
***ON RT
Properties of ionic compounds
- HIGH melting and boiling points
- DO form crystals
- DO dissolve in water
- DO conduct electricity in a solution and as a liquid
Properties of covalent/molecular compounds
- LOWER melting and boiling points
- DO NOT form crystals
- INsoluble in water
- do NOT conduct electricity
OPPOSITE OF IONIC
How are metallic bonds formed?
valance electrons are mobile in a free moving “sea of electrons”
Combined gas law-relationship between…
-pressure and volume
-temperature and pressure
-temperature and volume
relationships between pressure, temp, and volume in sample of GAS
P and V: INVERSE
T and V: direct
T and P: direct
What is an ideal gas? When is a real gas most like an ideal gas?
Hypothetical gas model where molecules:
1. don’t repel or attract move in straight lines
2. move in straight lines with random motion
3. collisions result in transfer of energy but NO NET LOSS OF ENERGY
4. negligible volume
A real gas is most like an ideal gas when it’s at LOW temp and HIGH pressure
When will equal volumes of gas have an equal number of particles?
At the same temperature and pressure
potential and kinetic energy meaning? During a flat line what is happening to both? what about increasing line?
P: stored energy
flat line= (phase change) will increase
increasing line= stays the same
K: energy of motion
flat line=(phase change) will stay same
increasing line= increases
ONE CHANGES AT A TIME
Temp vs heat
Temperature: measures average kinetic energy, NOT form of energy
Heat: transfer of energy (usually thermal) from body of higher temp to lower
What is it called going from…
-gas to liquid
-liquid to gas
-liquid to solid
-solid to liquid
-gas to solid
-solid to gas
Gas to liquid: Condensation
Liquid to Gas: Vaporization
Liquid to Solid: Solidification (freezing)
Solid to liquid: Fusion (melting)
Gas to solid: deposition
Solid to gas: sublimation
When progressing across a period and down a group, what happens to:
-atomic radius
-metallic character
-electronegativity
-ionization energy
GROUP:
atomic radius INCREASES
metallic character INCREASES
electronegativity DECREASES
ionization energy DECREASES
PERIOD:
atomic radius DECREASES
metallic character DECREASES
electronegativity INCREASES
ionization energy INCREASES
elements in a different form but in the same phase will have ____properties and _____molecular/crystal structure.
Different properties and different structure
which types of solvent do ionic and covalent compounds dissolve in? (polar or nonpolar)
Ionic= polar
Covalent= nonpolar
How will adding a solute to a solvent affect freezing and boiling points?
HIGHER boiling point
LOWER freezing point
What’s the collision theory?
Theory that a reaction is most likely to occur when particles collide with proper ENERGY and ORIENTATION
what is entropy and enthalpy? what do systems in nature tend to lead toward?
entropy: randomness
enthalpy: energy
systems in nature tend to lead toward higher entropy and lower enthalpy
what are the reactants and products of neutralization reactions?
R:
Arrhenius base and acid
P:
water and a salt
What does a lower vs higher pH mean for the concentration of H+? what does one pH unit =?
Lower pH= more acidic-higher concentration of acid(H+)
1 unit lower=10x greater concentration
Higher pH= less acidic-higher concentration of base(OH-)
1 unit higher=10x lower concentration
how is electricity produced?
by moving electrons from one atom to another
how to determine if redox reaction is SPONTANEOUS?
metals: oxidized is always HIGHER than reduced
nonmetals: reduced is always HIGHER than reduced
voltaic cells
- chemical to electrical energy
- spontaneous MEANING cathode is lower than anode
- salt bridge (promotes ion exchange and maintains electrical neutrality)
electrolytic cells
- electrical energy to chemical
- not spontaneous
- electroplating (plating) and electrolysis (splitting water molecules)
how do you determine which atom has the greatest attraction for the electrons in a chemical bond?
the one with the highest electronegativity
energy is ___ when bonds are broken and is _____ when bonds are formed.
broken: energy is absorbed
formed: energy is released
according to LeChatelier’s principle, what changes would cause a shift in equilibrium?
temp,
volume,
concentration,
and pressure (only when there are gases on P or R side)
what is the homologous series for unsaturated organic compounds?
CnH(2n+2)
how many significant figures do you round your answer to when…
-multiplying
-dividing
-adding
-subtracting
for any problem, always round to the smallest number of sig figs!
Example:
1.0 + 3.24= round to 2 sig figs
when naming polyatomic ions ending in -ite, what does this ending change to?
-ous
which type of bonds are malleable and which are ductile?
metallic= ductile AND malleable
(ionic and covalent=not malleable, not ductile)
when a sample is cooled, which property will increase?
density because the sample will contract
distillation
separating MIXTURES based on their different boiling points
how does providing a catalyst affect the reaction’s potential and activation energy?
lowers activation energy and the potential energy stays the same
how do you identify a nonpolar/polar molecule? how do you identify nonpolar/polar bonds?
MOLECULE: symmetrical=nonpolar, asymmetrical=polar
BONDS: equal electronegativities=nonpolar, unequal electronegativities=polar
review electronegativity differences
What electronegativity differences would make a bond polar?
0-0.4 is nonpolar covalent
BETWEEN 0.4-1.7 is polar covalent
1.7 and greater is ionic (polar)
how do you identify which solution will have the HIGHEST boiling point?
- know that more ions=higher boiling point
- look at table S to see which has a higher BP
saturated hydrocarbon:
-# of bonds
-formula
will have SINGLE bonds
formula is CnH2n+2(RT Q)
What type of solutions are electrolytes?
Salts, bases and acids.
Common bases/acids are found on table K and L and salts are compounds that can conduct electricity (ionic and metallic compounds)
Properties of metallic compounds
high BP and FP
malleable
can conduct electricity due to the sea of electrons that allows ions to move and conduct
ionic and covalent binary compound…
-endings
-what to include when naming
binary IONIC: “-ide” (include oxidation states)
binary COVALENT: “ide” (include PREFIXES on table P to show number of atoms)
***Nitrogen MONoxide (never add mono to first atom)
prefixes 1-4 (rest on table P)
mono
di
tri
tetra
equation to convert C to K and K to C
(Table A)
K= C + 273
C= K - 273
which elements will create a hydrogen bond with hydrogen?
Fluorine, Oxygen, and Nitrogen
Hold
the
FON
this will have: hydrogen, van der waal, and dipole-dipole IFA
van der waal forces
exist in everything
IFA that will hold bonds together, hydrogen bonds and dipole-dipole are a type of this
mixture vs compound
compound: 2 or more substances BONDED
mixture: 2 or more substances NOT BONDED
examples- AIR, mud, smog, sea water
what two factors can show a CHEMICAL reaction at equilibrium?
- a different substance is formed
- the forward and reverse rate of reaction is the same
NOT PHASE CHANGES
identifying factors of saturated and unsaturated hydrocarbons
SATURATED: alkANEs
-the maximum amount of H are there
UNSATURATED: alkENEs and alkYNEs and aromatic rings
-more H could be bonded to a C
how can you identify the polarity of a molecule using chromotography?
lower polarity will move faster and therefore travel farther
higher will move slower and travel smaller distance
properties of metals vs nonmetals vs metalloids
metals: good conductors, high melting point, usually solid at room temp., malleable and ductile
nonmetals: worse conductors, low melting point, usually liquid or gas at room temp., brittle
metalloids: right in the middle except ARE malleable and ductile
what is ionization energy
the amount of energy needed to remove the most loosely held electron from a gaseous atom
going down a group: decreases
going across a period: increases
HIGHER IE means needs MORE energy to remove
