Semester 2 Final Exam Review – Answer Key
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Mendeleev
Electrons in the outer-most energy shell of an atom
F, O, N
–ide
Atoms with a full valence shell
Molarity (M) = moles per liter = moles/liters
Basic, alkaline
Group or Family
6.02 x 10^23 x 5 = 3.01 x 10^24
Fluid, compressible, take the shape and volume of the container, molecules are far apart (low
density)
Period
Acidic
High boiling point, low vapor pressure
A homogeneous mixture of only one phase; solute dissolved in a solvent
22.4L
Endothermic
Zn(NO3)2
H, N, O, F, Cl, Br, I
Nature of the reactants, temperature, surface area, concentration, catalyst
Calorie = energy required to raise 1g of water 1 degree Celcius
Volume is directly proportional to temperature @ a constant pressure (V1/T1 = V2/T2)
Iron(II) chloride
Ba(NO3)2
PbCO3
Reactants react to form products
Synthesis, decomposition, combustion, single replacement, double replacement
Water and carbon dioxide
Right side, -ΔH
The energy require to form an activated complex and have a reaction proceed to form products
Exothermic, ΔH = -585kJ
 Convert mass to moles: 34g ÷ 17g/mol = 2 mol NH3
 Multiply by energy/mole ratio: 2 mol NH3 x (-1170kJ)/4 mol NH3 = -585kJ
Concentration, temperature, pressure (gas, heterogeneous system)
A buffer solution is a solution of a conjugate acid-base pair. A buffer system prevents significant
changes in pH when a small amount of acid or base is added to the solution. Your body has a
bicarbonate buffer system in the blood which helps maintain you blood’s pH.
Unsaturated = more room for solute @ temp; saturated = solute maxed out @ temp;
supersaturated = more solute than maximum for given temp
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Sucrose = 45 atoms, just add up the individual atoms
Al2(SO4)3 = 17 atoms
Heterogeneous mixture = different composition in different places (pulp & juice)
Conjugate acid-base pair in solution
Pressure = force per unit of area; N/m2
Chemical salt and water
A substance that lowers the activation energy of a chemical reaction by utilizing an alternative
pathway. Catalysts are not used up in a chemical reaction.
Temperature
When the forward and reverse reactions occur at the same rate
ΔH = (25g x 10°C x 1cal/g°C) = 250 cal = 0.25 Cal
Carbon monoxide; aluminum acetate
Heat is the energy transferred between objects at different temperatures; temperature is the
average kinetic energy of the molecules in a substance
Add up the molar masses of each atom present = 180g
Calcium chlorate, silicon dioxide, carbon tetrachloride, potassium permanganate
1 atm and 0 degrees Celsius (273K)
Pressure is inversely proportional to volume @ a constant temp (P1V1 = P2V2)
The amount of heat required to raise the temperature of 1 gram of a substance 1 degree celcius
1.34 moles x 22.4 L/mol @ STP = 30.016L
The volume of 1 mole of a gas
N2 = non-polar covalent; MgCl2 = ionic; CO2 = non-polar covalent (due to shape)
Ionic bonds = bonds formed due to electrostatic attraction between cations & anions; covalent
bonds = bonds formed by the sharing of electrons between atoms
Hydrogen gas + oxygen gas  water
 2H2 + O2  2H2O
 synthesis
Potassium Iodide + Lead (II) Nitrate  Potassium Nitrate + Lead(II) Iodide
 2KI + Pb(NO3)2  2KNO3 + PbI2
 Double replacement
Methane + Oxygen Gas  Carbon Dioxide + Water
 CH4 + 2O2  CO2 + 2H2O
 Combustion
Hydrochloric Acid + Zinc  Zinc Chloride + Hydrogen Gas
 2HCl + Zn  ZnCl2 + H2
 single replacement
Hydrogen Carbonate (carbonic acid)  carbon dioxide + water
 H2CO3  CO2 + H2O
 Decomposition
Homogeneous: salt water (solution); heterogeneous: muddy water (suspension); graphite (pure
carbon)
61. The amount of dissociation of the acid (all acid molecules versus a few)
62. Acid <7, base>7, neutral = 7
63. Acids: sour, electrolytes, react with metals to form hydrogen gas, react with carbonate to form
carbon dioxide, turn blue litmus red, pH<7
64. Bases: bitter, electrolytes, slippery, pH >7
65. Oxidation = loss of electrons
66. Reduction = gain of electrons
67. Redox reactions are reactions in which electrons are transferred from one element to another.
The reaction in a battery is an example of a redox reaction.
68. Anode is where oxidation occurs & Cathode is where reduction occurs
69. Anion = negative ion; cation = positive ion
70. Enthalpy is the amount of energy stored in a compound (i.e., heat content)
71. T increase = P increase and vice-versa; V increase = T increase and vice-versa; P increase = V
decrease
72. Abs. value of (3.51 – 3.74)/3.51 = 0.065 x 100% = 6.5% error
73. Liters, grams, meters
74. Ptotal = P1 + P2 + P3….etc.
75. Chemical change = change in identity of substances; physical change = no change in identity of
substances
76. A polar molecule has a charge differential (like a magnet); a non-polar molecule does not
present a charge differential
77. Phoenix  Flagstaff (decrease in pressure); volume of air sample will increase; density will
decrease
78. 0.638 mole x 189.3g/mol = 121 g
79. 106.2g ÷ 180g/mol = 0.59 mol
80. 8.96 x 10^22 ÷ 6.02 x 10^23 = 0.149 mol
81. 44.3g ÷406.3g/mol = 0.109 mol ÷0.250L = 0.436 M (M = molarity = concentration)
82. 5.23 g ÷ 123.5g/mol = 0.0423 mol ÷ 0.100L = 0.423 M
83. (Xmol)÷(0.5L) = 0.500M, X = (0.500M) x (0.5L), X = 0.25 mol
84. X mol ÷ 0.050L = 0.75M, X = 0.75M x 0.050L = 0.0375 mol x 35g/mol = 1.31 g NH4OH
85. ΔH = 1,760g x 67°C x 1cal/g°C = 117,920 cal = 117.92 Cal
86. 320g ÷ 159.8g/mol = 2.00mol Br2 x 72.80kJ/1mol Br2 = 145.8 kJ, Endothermic (+ΔH)
87. ΔH = 425g x 175°C x 0.897J/g°C = 66,714 J
88. Cp = 793.86J/(128g x 14°C) = 0.443J/g°C
89. ΔH = 1000g x 45°C x 1cal/g°C = 45,000cal ÷ 5g butter = 9000 cal/g butter
90. ΔH = 4110g x 635°C x0.897J/g°C = -2,341,035J lost (-ΔH)
91. Cp = 550.25J/(21.5g x 57°C) = 0.449J/g°C
92. P1V1 = P2V2, (730mmHg)(76mL) = (978mmHG)(V2), V2= 56.7mL
93. P1V1 = P2V2, (180kPa)(75mL) = (101.325kPa)(V2), V2 = 133mL
94. V1/T1 = V2/T2, Temp in KELVIN (380mL)/(301K) = (145mL)/(T2), T2 = 114.9K – 273 = -158.1°C
95. V1/T1 = V2/T2, (356mL)/(313L) = (V2)/(294K), X = 334mL
96. (P1V1)/T1 = (P2V2)/T2, [(1125kPa-70.1kPa)x350mL]/363K = (980kPa x V2)/285K, V2 = 295mL
97. (P1V1)/T1 = (P2V2)/T2, [(950kPa – 2.6kPa)x115mL]/295K = (101.325kPa x V2)/273K, V2 = 995mL
98. (P1V1)/T1 = (P2V2)/T2, (760mmHg x 0.355L)/273K = (833mmHg x V2)/297K, V2 = 0.352L
99. Missing
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PV = nRT, MUST BE IN LITERS, (149kPa)(15.9L) = n(8.314)(301K), n = 0.947 moles
101.
PV = nRT, (1.5atm)(V) = (0.275mol)(0.082)(298K), V = 4.47L
102.
Asprin = 328g
 Find moles of salicylic acid: 251.75g ÷ 138g/mol = 1.82 mol SA
 multiply by mole ration from balance equation: 1.82 mol SA x (1 mole Asprin)/(1 mol SA)
= 1.82 mole asprin
 Convert moles asprin to mass: 1.82 mole x 180g/mol = 328g asprin
103.
2Al + Fe2O3  Al2O3 + 2Fe, 4.3g Al2O3
 Convert mass Al to moles: 2.3g ÷ 27g/mol = 0.085 mol Al
 Multiply by mole ration of Aluminum oxide over aluminum: 0.085 mol Al x (1 mol
Al2O3)/(2 mol Al) = 0.0426 mol Al2O3
 Convert to mass: 0.0426 mol Al2O3 x 102g/mol = 4.3 g Al2O3
104.
2KClO3  2KCl + 3O2 1.53 mol O2
 Convert mass to moles: 125g ÷ 122.5g/mol = 1.02 mol
 Multiply by mole ratio: 1.02 mol x (3 mol O2)/(2 mol) = 1.53 mol O2
105.
C3H8 + 5O2  3CO2 + 4H2O 73.5g propane
 Multiply by mole ratio: 8.35 mol O2 x (1 mole propane)/(5 mol O2) = 1.67 mol propane
 Convert to mass: 1.67 mol x 44g/mol = 73.5g propane
106.
2CO + O2  2CO2 12.3L oxygen
 Convert volume to moles: 24.8 L ÷ 22.4L/mol = 1.1 mol CO
 Multiply by mole ratio: 1.1 mol CO x (1 mol O2 )/(2 mol CO) = 0.55 mol O2
 0.55 mol O2 x 22.4L/mol = 12.3L oxygen; 24.6L CO2
107.
NaOH + HCl  NaCl + H2O
108.
Sa x Ma X Va = Sb x Mb x Vb, (1 x 3M x 10mL) = (1 x Mb x 33mL), Mb = 0.9M
109.
Sa x Ma X Va = Sb x Mb x Vb, (1 x Ma x 10mL) = (1 x 0.5M x 30mL), Ma = 1.5M
110.
Sa x Ma X Va = Sb x Mb x Vb, (1 x 0.1M x 10mL) = (2 x Mb x 5.0mL), Mb = 0.1M
111.
Standard solution = titrant, solution of known concentration; endpoint = point of color
change; acid-base titration = method of determining the concentration of an acid or base of
unknown molarity by using a solution of known concentrations in a neutralization reaction.
112.
Cu is oxidized (loses e-), Ag is reduced (gains e-)
113.
Entropy = measure of disorder in a system. Ice has low entropy compared to water
114.
3 mol x (6.02 x 10^23 molecules/mol) = 1.81 x 10^24 molecules of oxygen
115.
NH3 = ammonia, CH4 = mthane, HCl = hydrochloric acid, H2SO4 = sulfuric acid
116.
Not on graph
117.
Sodium nitrate – cure changes the most in response to temperature change
118.
5g salt, there is 10g of potassium chlorate in 100g of water at 23°C, so half that in 50g of
water
119.
20g KCl
120.
90°C
121.
NH3, CH4, HCl, H2SO4, HC2H3O2, NaOH
122.
U = 92 e-, 92 p, 143 n; Pd = 46 e-, 46 p, 60 n; O = 8 e-, 8 p, 10 n
123.
1 x 10-8 M
124.
pOH = 3, pH = 11
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0.563 L
126.
1.234 g
127.
0.245 km
128.
27 mL
129.
0.4 cm
130.
8900 cm
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3.829 m
132.
Oxygen decreased = products, temp decreased = products
133.
Temp increase = reactants
134.
Pressure decrease = no change because same # of moles of gas on each side
135.
Endothermic, A = PE reactants, B = PE activated complex, C = Activation energy, D = ΔH,
E = PE Products