EOC Final Exam – Review Sheet 3
Stoichiometry, Gas Laws, Physical Changes, Graphs
1) A compound contains 0.5 mole of sodium, 0.5 mole of nitrogen, and 1.0 mole of hydrogen. What is the empirical formula for this compound?
a) NaNH b) Na2NH c) NaNH2 d) NaN2H2
2) The empirical formula for a compound is CH. The molecular formula for this compound could be
a) CH4 b) C2H2 c) C2H4 d) C3H8
3) Which quantity of LiF has a mass of 39 grams?
a) 1.0 mole b) 2.0 moles c) 0.5 mole d) 1.5 moles
4) What is the gram-formula mass of gypsum, CaSO4 2H2O?
a) 172 g b) 154 g c) 136 g d) 118 g
5) A compound has an empirical formula of CH2 and a molar mass of 56. Which is its molecular formula?
a) C2H4 b) C3H6 c) C4H8 d) C5H10
6) The empirical formula of a compound is CH2; its formula mass is 70. What is the molecular formula of the compound?
a) C2H2 b) C2H4 c) C4H10 d) C5H10
7) What is the molecular formula of a compound whose empirical formula is CH2 and whose molar mass is 42?
a) HCOOH b) C2H2O c) C3H6 d)C3H8
8) The atomic mass unit is defined as exactly
a) 1/12 the mass of a carbon-12 atom
b) 1/14 the mass of a nitrogen-14 atom
c) 1/16 the mass of an oxygen-16 atom
d) the mass of a hydrogen atom
9) What is the mass, in atomic mass units, of an ion that contains 18 electrons, 15 protons, and 16 neutrons?
a) 49 amu b) 33 amu c) 31 amu d) 15 amu
10) What is the percent by mass of oxygen in Fe203?
a) 2.3% b) 30% c) 56% d) 70%
11) The mass ratio of sulfur to oxygen in sulfur dioxide is
a) 1:1 b) 1:2 c) 2:3 d) 3:2
12) What is the total mass of iron in 1 mole of Fe203?
a) 160 g b) 112 g c) 72 g d) 56 g
13) What is the ratio by mass of carbon to hydrogen in the compound C2H6?
a) 6:2 b) 2:6 c) 1:4 d) 4:1
14) As a sample of Na2CO3 10 H2O is heated in an open crucible, the mass of the contents of the crucible
a) increases b) decreases c) remains the same
15) A 10-gram sample of a hydrate was heated until all the water of hydration was driven off. The mass of the anhydrous product remaining was 8.0 grams. What is the percent by mass of water in the hydrate?
a) 12.5% b) 20% c) 25% d) 80%
16) Given the balanced equation: 2 Na + 2 H2O è 2 X + H2, what is the correct formula for the product represented by the letter X?
a) NaO b) Na2O c) NaOH d)Na2OH
17) When the equation C2H4+ O2 è CO2 + H2O is completely balanced using smallest whole numbers, what is the coefficient of O2?
a) 1 b) 2 c) 3 d) 4
18) Given the reaction: 2 CO + O2 è 2 CO2. What is the minimum number of moles of O2 required to produce 1 mole of CO2?
a) 1.0 b) 2.0 c) 0.25 d) 0.50
19) Given the reaction: Ca + 2 H2O è Ca(OH)2 + H2; what quantity of H2O will react exactly with 2.0 mol of Ca?
a) 1.0 mol b) 2.0 mol c) 0.50 mol d) 4.0 mol
20) Given the reaction: 2 NaOH + H2S04 è Na2S04 + 2 H2O what is the number of moles of NaOH needed to react completely with 2 moles of H2SO4?
a) 1 b) 2 c) 0.5 d) 4
21) What is the number of molecules in 1 mole of ammonia, NH3?
a) 1 X 1023 c) 6.02 X 1023
b) 12 X 1023 d) 24.2 X 1023
22) Which expression represents the number of atoms in 44 grams of carbon dioxide?
a) 3(6.02 x 1023) c) 6(6.02 x 1023)
b) (6.02 x 1023)/6 d) (6.02 x 1023)/2
23) What is the molar mass of a gas with a density of 1.78 grams per liter at STP?
a) 17.8 g b) 22.4 g c) 39.9 g d) 79.6 g
24) What is the number of atoms in 46.0 grams of sodium?
a) 3.01 X 1023 c) 6.02 X 1023
b) 12.0 X 1023 d) 24.0 X 1023
25) Given the reaction: 2 C2H6+ 7 O2 è 4 CO2 + 6 H2O; what quantity in moles of CO2 is produced when 30.0 grams of C2H6 is burned completely?
a) 1.0 b) 2.0 c) 8.0 d) 4.0
26) What mass of oxygen is produced by the decomposition of 3.0 moles of water:
2 H2Oè 2 H2 + O2
a) 1.5 g b) 32 g c) 36 g d) 48 g
27) Given the reaction (all quantities measured at STP): 4 NH3 + 5 O2 è 4 NO + 6 H2O; what volume of O2 is required to produce 80.0 L of NO (g)?
a) 5.0 L b) 64.0 L c) 80.0 L d) 100.0 L
28) A 60-gram sample of LiCl H2O is heated in an open crucible until all the water has been driven off. What is the mass of LiCl that remains in the crucible?
a) 18 g b) 24 g c) 42 g d) 60 g
29) A compound is found to contain 85.6% carbon and 14.4% hydrogen. What is its empirical formula?
a) CH b) CH2 c) C2H d) C2H2
30) The molar mass of a given gas is 44.0 grams. What is its density at STP?
a) 0.509 g/L b) 1.43 g/L c) 1.96 g/L d) 2.84 g/L
31) What is the volume of 4.00 moles of N2 gas at STP?
a) 11.2 L b) 22.4 L c) 44.8 L d) 89.6 L
32) The density of a gas is 2.0 grams per liter at STP. Its molar mass is approximately
a) 67 b) 45 c) 22 d) 8
Questions 33-35 are based on Reference Table G
33) A solution contains 90 grams of salt dissolved in 100 grams of water at 40°C. The solution could be an unsaturated solution of
a) KCl b) KNO3 c) NaCl d) NaNO3
34) Which of the following substances is most soluble (in grams per 100 g of water) at 60°C?
a) NH4Cl b)KCl c) NaCl d)NH3
35) What mass of sodium chloride is required to saturate 500 grams of water at 50°C?
a) 38 g b) 50 g c) 190 g d) 500 g
36) What quantity of H2SO4 is needed to prepare 5 L of a 2.0 M solution of H2SO4?
a) 2.5 moles b) 5.0 moles c) 10 moles d) 20 moles
37) What is the mass of KCl (molar mass 74.6 g) in 1 L of 0.200M solution?
a) 7.46 g b) 14.9 g c) 22.4 g d) 29.8 g
38) What is the molarity of a solution that contains 80 g of NaOH (molar mass 40 g) in 4.0 liters of solution?
a) 0.50 M b) 2.0 M c) 8.0 M d) 20.0 M
39) If 0.50 liter of a 12 M solution is diluted to 1.0 liter, what is the molarity of the new solution?
a) 2.4 M b) 6.0 M c) 12.0 M d) 24.0 M
40) What is the molarity of a solution of KNO3 (molar mass = 101) that contains 404 grams of KNO3 in 2.0 liters of solution?
a) 1.0 b) 2.0 c) 0.50 d) 4.0
41) Which of the following lists gives the classes of fluid mixtures in order of increasing size of dispersed particles?
a) solution, suspension, colloid
b) colloid, suspension, solution
c) suspension, colloid solution
d) solution, colloid, suspension
42) Compared with pure water, a 0.5 M solution of NaCl will have a
a) higher boiling point and a higher freezing point
b) higher boiling point and a lower freezing point
c) lower boiling point and a higher freezing point
d) lower boiling point and a lower freezing point
43) Which 1.0 molar solution has the lowest freezing point?
a) NaCl (molar mass 58.5 g/mol)
b) K2CO3 (molar mass 138 g/mol)
c) CuSO4 (molar mass 160 g/mol)
d) C6H12O6 (molar mass 180 g/mol)
44) When one mole of Na2SO4 dissolves in water, the number of moles of ions formed is
a) 6 b) 2 c) 3 d) 7
45) When 168 joules of heat is added to 4 grams of water at 283 K, the resulting temperature is
a) 10K b) 200 K c) 273 K d) 293 K
46) When the temperature of a system increases by 20 Celsius degrees, the corresponding temperature change on the Kelvin scale is
a) +20 b) -20 c) +293 d) -253
47) Which Kelvin temperature is equivalent to 20°C?
a) 20 K b) 253 K c) 273 K d) 293 K
48) A true solution is best described as a
a) heterogeneous compound
b) homogeneous compound
c) heterogeneous mixture
d) homogeneous mixture
49) Which formula represents a mixture?
a) NaCl(aq) b) NaCl(s) c) H2O(l) d) H2O(s)
50) Which change of phase is exothermic?
a) gas to liquid c) solid to liquid
b) solid to gas d) liquid to gas
51) What is the normal boiling point of water?
a) 173 K b) 273 K c) 373 K d) 473 K
52) Which of the following best describes exothermic chemical reactions?
a) They never release heat.
b) They always release heat.
c) They never occur spontaneously.
d) They always occur spontaneously.
Base your answers to questions 54 and 55 on the following graph, which represents the uniform heating of a water sample at standard pressure, starting at a temperature below 0°C.
53) The amount of heat required to vaporize the entire sample of water at its boiling point is represented by the interval between
a) A and B b) E and F c) C and D d) D and E
54) When the temperature of 5.0 grams of water changes from C to D, what is the total energy absorbed?
a) 334 J b) 420 J c) 750 J d) 2100 J
55) Which substance has a definite shape and a definite volume at ordinary conditions?
a) NaCl(aq) b) Cl2(g) c) CCl4(l) d) AlCl3(s)
56) What is the maximum mass of water that can be heated from 298 K to 303 K by the addition of 1260 joules of heat?
a) 3,000 g b) 300 g c) 60 g d) 10 g
57) Which system contains molecules with the same average kinetic energy as the molecules in 10.0 grams of carbon dioxide at 10°C?
a) 10 grams of CO2 at 40°C
b) 20 grams of CO2 at 0°C
c) 20 grams of CO2 at 20°C
d) 40 grams of CO2 at 10°C
58) Which of the following is a principle of the kinetic- molecular theory?
a) Molecules of a gas bond together following collisions.
b) As temperature decreases, gas molecules maintain constant velocities.
c) Strong forces of attraction exist between molecules of a gas.
d) The distances between molecules of a gas are much greater than the diameters of the molecules.
59) A sample of gas has a volume of 2.00 liters at a pressure of 202 kPa and a temperature of 298 K. When the volume of the gas increases to 3.00 liters and the pressure increases to 404 kPa, the temperature will be
a) 1.12 X 10-3 K b) 596K c) 894 K d) 1780 K
60) A sample of helium has a volume of 10.0 liters at a pressure of 10.0 atm and a temperature of 596 K. What is the pressure in atm when the temperature decreases to 298 K and the volume increases to 15.0 liters?
a) 0.667 b) 1.50 c) 1.67 d) 3.33
Base your answers to questions 61-63 on the following graphs.
61) Which graph best represents how the volume of a given mass of a gas varies with increasing temperature at constant pressure?
a) 1 b) 2 c) 3 d) 5
62) Which graph best represents temperature in a system that undergoes a temperature change and a phase change as heat is added at a constant rate?
a) 1 b) 2 c) 3 d) 4
63) Which graph best represents the mass of a sample of gas as pressure increases at constant temperature?
a) 5 b) 2 c) 3 d) 4
64) The pressure exerted by a gas is due to
a) Nuclear forces in the atoms of the gas
b) Gravitational forces between gas atoms
c) collisions of molecules with each other
d) collisions of molecules with the container's walls
65) How much heat energy is needed to vaporize 100 g of water at its boiling point of 373 K?
a) 22.6 J b) 226 J c) 22,600 J d) 226,000 J
66) The term fusion refers to
a) warming only c) condensation only
b) melting only d) condensation & melting
67) In a closed system, as temperature increases, the vapor pressure of a confined liquid
a) increases b) decreases c) remains the same
68) When heat energy is lost by a pure substance at its freezing point with no change in temperature, its potential energy
a) decreases b) increases c) remains the same
69) Which change of phase represents sublimation?
a) solid to liquid c) solid to gas
b) liquid to gas d) liquid to solid
70) As temperature increases, the vapor pressure of water
a) increases b) decreases c) remains the same
71) At 1 atmosphere, which substance will sublime when heated?
a) CO2(s) b) H2O(s) c) CH4(g) d) HCl(aq)
72) As heat is applied to a piece of ice at 0°C, the temperature of the ice initially
a) decreases b) increases c) remains the same
73) As the temperature is increased, the volume of a mole of gas at constant pressure
a) decreases b) increases c) remains the same
74) As its temperature decreases, the molar mass of a sample of oxygen at constant pressure
a) decreases b) increases c) remains the same