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Question #1• Which of the following atoms
contains 30 protons, 40 neutrons and 28 electrons?
• A: 70 Zn+2
• B: 70 Zn-2
• C: 40 Zn+2
• D: 30 Zr-2
Answer to Q#1• Letter A: 70 Zn+2 is the answer.• Why? The format for chemical
symbols is A Xcharge
z
• Remember, A = mass, which equals protons + neutrons
• Z = atomic number = protons• Charge = protons – electrons
Question #2• The element boron has only two stable
isotopes. One stable isotope has a mass number of 10 and the other has a mass number of 11. Which of the following could be the atomic weight of the element?
• A: 9.5• B: 10.8• C: 11.7• D: 12.4
Answer to Q#2• Letter B: 10.8 is the answer• Why? The mass of an element
on the periodic table is the weighted average of all the isotopes of that element
Question #3• An atom of Argon—40 contains—• A: 18 protons and 18 neutrons• B: 18 protons and 22 neutrons• C: 18 protons and 40 neutrons• D: 20 protons and 20 neutrons
Answer to Q#3• Letter B: 18 protons and 22
neutrons• Why? The 40 in Argon-40 is the
mass of the isotope• Remember mass = protons +
neutrons (electrons have no mass)• Argon has an atomic number of
18, so there 18 protons
Isotope/ Ion Quick Review• Isotopes of an element have the same
atomic number (protons) but different masses (hence different neutrons)
• Both protons and neutrons have a mass of 1
• Electron’s mass is not taken into account in the mass of an atom
• Ions are anything with an electrical charge
• Positively charged ions have lost electrons
• Negatively charged ions have gained electrons
Question #4• A scientist comparing K and Ca
would find that K has a—• A: lower electronegativity and a
smaller atomic radius• B: higher electronegativity and a
smaller atomic radius• C: lower electronegativity and a
larger radius• D: higher electronegativity and a
larger atomic radius
Answer to Q#4• Letter C: lower electronegativity
and a larger atomic radius• Why? Electronegativity gets higher
as you go across a period and atomic radius gets smaller as you go across a period
• K is farther left so it must have a lower electronegativity and larger atomic radius
Answer to Q#5• Letter A: Cs• Why? All these elements are
metals—the most reactive metals are the largest
• Atomic radius gets larger as you go down a group
• Cs is farthest down so it is the largest and most reactive
Trends Quick Review• Trends as you go down a group:
larger atomic radius, lower electronegativity, lower and ionization energy (easier to lose an electron)
• Trends as you go across a period: smaller atomic radius, higher electronegativity, and higher ionization energy (harder to lose an electron)
• Remember IE is the energy it takes to lose an electron
• Electronegativity is the ability to gain an electron
Quick Review Continued• Metal reactivity: Largest metals
= most reactive metals.• Remember metals like to lose
electrons• Non-metal reactivity: smallest
non-metals = most reactive non-metals.
• Remember non-metals like gain electrons
• Noble gases are non-reactive—they have a full valence shell
Question #6• A bond between an element of
group 2 and an element of group 17 will be:
• A: ionic• B: Nonpolar covalent• C: Polar covalent• D: Metallic
Answer to Q#6• Letter A: Ionic• Why? Group 2 elements are
metals (also known as alkaline earth metals) and group 17 (or 7) elements are non-metals (also known as halogens)
• Metals + non-metals = ionic bonding
Bonding Quick Review• Covalent bonding = sharing of
electrons between non-metals• Ionic bonding = transferring of
electrons between metal + non-metal
• Nonpolar covalent bond = equal sharing of electrons between non-metals
• Polar covalent bond = unequal sharing of electrons between non-metals
Question #7• What is the name for Cu2S?• A: Copper sulfide• B: Copper (I) sulfide• C: Dicopper sulfide• D: Dicopper monosulfide
Answer to Q#7• Letter B: Copper (I) sulfide• Why? Copper is a transition (d
block) metal, so you must use roman numerals to indicate its charge
• Look behind S for the charge of Cu.
• Charge is +1 so copper (I) sulfide
Question #8• Which of the following is the
formula for carbonic acid?• A: HC• B: HCO• C: HO• D: H2CO3
Answer to Q#8• Letter D: H2CO3
• Why? It’s an acid so H must come first. Carbonic = carbonate = CO3
-2
• H+1 + CO3-2 = H2CO3
Question #9• What is the molecular formula of
tetraphosphorus decoxide?• A: PO• B: P4O
• C: P4O10
• D: PO10
Answer to Q#9• Letter C: P4O10
• Why? Tetra = 4 and deca = 10• So P4O10
• Remember, when using prefixes don’t switch—simply write what’s given
Naming Quick Review• Must use roman numerals to
indicate charge of a transition metal
• Only use prefixes when the compound is all non-metals
• If an acid has hydro prefix then it’s H+element
• If no hydro prefix for an acid then it’s H+polyatomic
Question #10___C3H4 + ___O2 ___CO2 + ___H2O
• When the equation above is balanced, what is the sum of the coefficients?
• A: 4• B: 5• C: 8• D: 10
Answer to Q10• Letter D: 10• Why? C3H4 + 4O2 3CO2 + 2H2O;
so 1+4+3+2 = 10• Don’t forget the law of
conservation of mass says the reactants side = products side
Question #11• Which of the following is an
example of a decomposition reaction?
• A: 2AgCl 2Ag + Cl2
• B: CuO + H2O Cu(OH)2
• C: AgCl + Mg MgCl2 + Ag
• D: HCl + Na(OH) H2O + NaCl
Answer to Q #11• Letter A: 2AgCl 2Ag + Cl2
• Why? Decomposition is when you start with one reactant and break into 2 products
• Letter B = synthesis; letter C = single replacement and letter D = neutralization reaction
Question #12• 12 x 403 =• What is the answer to the above
problem expressed with proper sig figs?
• A: 5,000• B: 4800• C: 4830• D: 4836
Answer to Q#12• Letter B: 4800• Why? When multiplying or
dividing, you use lowest # of sig figs for your answer
• 12 only has two sig figs, so your answer can only have two
Question #13• How many atoms of Na are in
0.300 moles of Na?• A: 0.0131 atoms• B: 7.86x1021 atoms• C: 1.81x1023 atoms• D: 6.02x1023 atoms
Answer to Q#13• Letter C: 1.81x1023 atoms• Why? 0.300 moles Na x
6.02x1023atom 1 mole
= 1.81x1023 atoms
Question #14• How many moles are in a
342grams of CaO?• A: 6.10 moles• B: 56.1 moles• C: 1.92x104 moles• D: 3.67x1024 moles
Answer to Q#14• Letter A: 6.10 grams• Why? 342g x 1mole CaO = 6.10
moles 56.08 grams
• 56.08 grams is the molar mass of CaO from the Periodic Table
Moles Quick Review• When multiplying/dividing use lowest
# of sig figs for answer• When adding/ subtracting use lowest
# of decimal places for answer• MassMoles use mass of Periodic
Table = 1 mole• Moles Particles use 1 mole =
6.02x1023 particles• Moles Liters at STP use 1 mole =
22.4 L
Question #15Be + 2HCl BeCl2 + H2
• Using the above reaction, what mass of beryllium was consumed in the reaction if 4.0 moles of HCl were used?
• A: 2.0grams• B: 9.0 grams• C: 18.0 grams• D: 36.0 grams
Answer to Q#15• Letter C: 18.0 grams• Why? • 4.0molsHCl x 1mols Be x 9.01gBe
2 mols HCl 1 mole Be
= 18.0 grams Be
Letter #162C2H6 + 7O2 4CO2 + 6H2O
• In an experiment, 0.500 mols of C2H6 were reacted with 1.50 moles of oxygen gas. Which of the following is the limiting reactant in this experiment?
• A: C2H6
• B: O2
• C: CO2
• D: H2O
Answer to Q #16• Letter B: O2
• Why? 0.500molsC2H6 x 4mols CO2
2 mols C2H6
= 1.00 mols CO2
• 1.50molsO2x4mols CO2 = 0.857molsCO2
7 mols O2
• Since O2 produces less CO2, it must be the limiting reactant
• C and D shouldn’t even be choices b/c they are products!
Stoich Quick Review • Mass A Mols A Mols B Mass B• Go from mols A mols B using mol
to mol ratio from coefficients of balanced equation
• Limiting reactant is the one used up first. It also produces the smaller amount of product
• % yield = (actual/theoretical) x100• Can also use stoich to go from
mass/mols of A to liters of B; use 22.4 L = 1mol at STP
Question #17• Which of the following is NOT a
part of the kinetic molecular theory?
• A: Gases move in a straight, continual motion
• B: Gases have no volume themselves
• C: Gases participate in inelastic collisions
• D: Kinetic energy is directly related to temperature
• E: Gases feel no attractive forces
Answer to Q#17• Letter C: Gases participate in
inelastic collisions• Why? Gases actually participate in
elastic collisions. • The other 4 parts are all TRUE
Gas Laws Quiz Review• Boyle’s Law P1V1 = P2V2, where P
and V are inversely related.• Charles’ Law V1/T1 = V2/T2
• Gay-Lusac P1/T1 = P2/T2
• Combined Gas Law (P1V1)/T1 = (P2V2)/T2
• Ideal Gas Law PV = nRT, where R = 0.0821 (L*atm)/(mol*K)
More Gas Laws Review• Must always convert
temperature from celsius to KELVIN!
• Absolute zero is -273C or 0K!• Absolute zero is the point where
all motion slows down and stops• Dalton’s Law P1+P2+P3… = Ptotal
Question #18• Which of the
following phase changes occurs at the arrow?
• A: Sublimation• B: Melting• C: Evaporation• D:
Condensation
Answer to Q#18• Letter B: melting• Why? Graph
always goes S, L, G—look at pic on right
• The arrow points to line b/w solid and liquid
• Only phase changes there are melting (SL) or freezing (LS)
Phases Quick Review• 6 phases changes
– Melting (SL) --Freezing (LS)– Evaporation (LG) --Condensation (GL)– Sublimation (SG) --Deposition (GS)
• Molar heat of fusion = amount of energy needed to melt 1 mole of a substance
• Molar heat of vaporization = amount of energy needed to evaporate 1 mole of a substance
• Specific heat capacity = amount of energy needed to raise the temperature of 1 gram of a substance by 1˚C use q = mxCpxΔT
IMF Quick Review• Four different intermolecular
forces– London dispersion (weakest) =
nonpolar covalent molecules– Dipole-dipole = polar molecules– Hydrogen bonding = H connected to N,
O or F bonding to another O, N or F– Ionic (strongest) = metal + non-metal
• Don’t forget to do the arrow test to determine polarity of a molecule
Question #19• How many moles of MgCl2 are
present in 3.00 liters of a 0.150M MgCl2 solution?
• A: 0.0500 moles• B: 0.450 moles• C: 1.35 moles• D: 20.0 moles
Answer to Q#19• Letter B: 0.450 moles• Why? Molarity (M) = mols/liters• So 0.150 M = x/3.00 L• (0.150M)(3.00L) = x• X = 0.450 moles
Solutions Quick Review• Molarity(M)=mols of solute/L of
solution• Molality(m)=mols of solute/kg of
solvent• Freezing point depression:
ΔTf=(-Kf) (m)(n)
• Boiling point elevation ΔTB=(Kb)(m)(n)
• Remember if the solute is covalent, n = 1
Equilibrium Quick Review• Write K expressions as products
over reactants. Remember the coefficients in the balanced equation are used as exponents in the K expressions
• Solids and liquids are not included!• Catalysts lower the activation
energy of a reaction• Enthalpy (ΔH) and entropy (ΔS)
determine the spontaneity of a reaction
• - ΔH (exothermic) and +ΔS (more disorder) means a spontaneous reaction
Question #20• PCl5(g) + heat PCl3(g) + Cl2(g)
• Which of the following will cause an increase in the equilibrium concentration of Cl2 gas?
• A: The addition of PCl3 gas• B: The removal of PCl5 gas• C: A decrease in temperature• D: An increase in temperature
Answer to Q#20• Letter D: An increase in
temperature• Why? Heat is a reactant, so
increase reactant side, equilibrium shifts to product side
• Letter A causes shift to L; letter B causes shift to L; and letter C causes shift to L