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Chemistry I
Practice Exam
Name________________
Multiple Choice: Choose the best answer that completes each statement. Put all answers on your answer
sheet.
1. The mass of one mole of NaCl is
a. 88.53 g
b. 22.99 g
c. 58.44 g
d. 35.45 g
c. 178.9 g
d. 233.9 g
2. The molar mass for Mn(NO3)2 is
a. 84.94 g
b. 116.9 g
3. Which of the following is equal to one mole of any substance?
a. 6.02 x 1012
b. 1.204 x 1024
c. 3.01 x 10 23
d. 6.02 x 1023
c. 1.5
d. 2.0
4. How many moles are in 88.0 g of CO2?
a. 0.5
b. 1.0
5. How many grams are in 2.35 moles of ZnCl2?
a. 136 g
b. 320 g
c. 57.9 g
d. 68.0 g
6. How many moles of P are in 2.4 x 1024 atoms of P?
a. 1.0
b. 2.0
c. 3.0
d. 4.0
7. Which of the following contain equal number of atoms?
a. 47.88 g Ti and 65.39 g Zn
b. 22 g Ti and 30 g Zn
c. 65.39 g Ti and 65.39 g Zn
d. 47.88 moles Ti and 65.39 moles Zn
8. The relative amounts of the elements in a compound are expressed as the ?
a. empirical formula
b. percent composition
c. limiting reactant
d. theoretical yield
9. A formula with the lowest whole-number ratio of elements in a compound
a. empirical formula
b. molecular formula
c. ionic formula
d. covalent formula
10. At STP, 1 mol of any gas occupies what volume?
a. 1.25 L
b. 22.4L
c. 73.1 L
d. 146 L
11. If the empirical formula of a compound is CH, then a molecular formula of this compound could be
a. CH4
b. CH2
c. C2H4
d. C2H2
12. The percent composition of carbon in acetone, C3H6O, is
a. 20.7
b. 62.1
c. 1.61
d. 30.0
13. The empirical formula of a compound is CH2F. The molecular weight of this compound is 66.0 g.
The molecular formula of the compound is:
a. C4H8F4
b. C4H4F4
c. C2H4F2
d. CH2F
14. The data table below gives the temperature and pressure of four different gas samples, each in a
2-liter container.
Temperature and Pressure of Gas Samples
Gas Sample
He
Ne
CO2
CH4
Temperature
(K)
Pressure
(atm)
300.
300.
200.
300.
1.20
1.00
1.20
1.00
Which two gas samples contain the same total number of particles?
a. CH4 and CO2
b. He and CO2
c.
CH4 and Ne
d. He and Ne
15. The percent composition by mass of magnesium in MgBr2 (molar mass = 184 grams/mole)
is equal to
a.
24
x 100
184
b.
160
x 100
184
c.
184
x 100
24
d.
184
x 100
160
16. Given the balanced equation representing the reaction between propane and oxygen:
C3H8 + 5O2 → 3CO2 + 4H2O
According to this equation, which ratio of oxygen to propane is correct?
a.
5 gO2
1gC 3 H 8
b.
5molO2
1molC3 H 8
c.
10 gO2
11gC 2 H 8
d.
10molO2
11molC 2 H 8
17. The substance that controls the quantity of product that can be formed in a chemical reaction is
a. limiting reactant
b. theoretical yield
c. actual yield
d. percent yield
18. The maximum amount of product supposed to be formed from a chemical reaction.
a. limiting reactant
b. theoretical yield
c. actual yield
d. percent yield
19. Given the balanced equation representing a reaction:
F2(g) + H2(g) →2HF(g)
What is the mole ratio of H2(g) to HF(g) in this reaction?
a. 1:1
b. 1:2
c. 2:1
d. 2:3
20. Given the balanced equation representing a reaction:
4NH3 + 5O2 →4NO + 6H2O
What is the minimum number of moles of O2 that are needed to completely react with
16 moles of NH3?
a. 16 mol
b. 20. mol
c. 64 mol
d. 80. mol
21. The equation for the production of chalk, calcium carbonate is the following
CaCl2 + Na2CO3 →
CaCO3 + 2 NaCl
When 1.00 mole of CaCl2 reacts with 2.00 mole of Na2CO3 which of the following acts as the
limiting reactant?
a. CaCl2
b. Na2CO3
c. CaCO3
d. NaCl
22. Using the following equation find the number of grams of calcium hydroxide which can be produced
starting with 25.0 grams of calcium nitride.
Ca3N2 (s) + 6 H2O (l)
a. 12.5 g
→ 3 Ca(OH)2 (s) + 2 NH3
b. 25.0 g
c. 37.5 g
d. 75.0 g
23. According to the equation, N2O3(g) + 6H2(g) → 2NH3(g) + 3H2O(g) how many moles of NH3(g)
could be formed from the reaction of 0.22 mol of N2O3(g) with 0.87 mol of H2(g)?
a. 0.29 mol
b. 0.44 mol
c. 0.73 mol
d. 1.1 mol
24-27. Use the following information and balanced equation to answer the next four questions.
An important equation used to produce ammonia is as follows:
N2 (g) + 3 H2 (g)
→ 2 NH3
24. If 56.0 g of nitrogen is reacted with 15.0 g hydrogen which substance is the limiting reactant?
a. N2
b. H2
c. NH3
d. H2O
25. Calculate the number of grams of reactant in excess.
a. 2.00 g
b. 3.00 g
c. 6.00 g
d. 12.0 g
c. 68.0 g
d. 85.0 g
26. What is the theoretical yield of NH3?
a. 34.0 g
b. 50.0 g
27. The actual yield of NH3 from this reaction is 33.5 g, what is the percent yield?
a. 39.4%
b. 49.3%
c. 67.0%
d. 98.5%
28. For a gas with temperature and number of moles are held constant, Boyle’s law describes a situation
in which:
a. volume and pressure have no relationship
b. volume increases with increasing pressure
c. volume decreases with decreasing speed
d. volume decreases with increasing pressure
29. The letters STP stand for:
a. solid, time, and pressure
b. solid, temperature and pressure
c. standard time and pressure
d. standard temperature and pressure
30. The tendency of molecules to move towards areas of lower concentration until the concentration is
uniform throughout.
a. diffusion
b. effusion
c. ideal gas
d. pressure
31. As the temperature of a fixed volume of gas increases, the pressure will
a. vary inversely
b. decrease
c. be unchanged
d. increase
32. A gas has a volume of 300 mL at a pressure of 105 kPa. The volume at standard pressure is
a. 857 mL
b. 105 mL
c. 311 mL
d. 289 mL
33. Oxygen gas at 293 K and 100. kPa occupies 500.mL What volume will the gas occupy at 303 K if
the pressure does not change.
a. 471 mL
b. 483 mL
c. 503 mL
d. 517 mL
34. The ideal gas law states that:
a.
P
= nRT
V
b.
V
= nRT
P
c. PV = nRT
d. PT = nRV
35. What volume will 10.0 g of Ne occupy at STP?
a. 8.21 L
b. 11.2 L
c. 22.4 L
d. 44.8 L
36. Which of the following gas molecules have the greatest average velocity (speed)?
a. CO2
b. NH3
c. Cl2
d. HCN
37. Calculate the partial pressure of oxygen gas is a mixture of three gases, O2, N2, and CO2, when the
total pressure is 100 kPa and the sum of the partial pressures of N2 and CO2 is 50 kPa.
a. 25 kPa
b. 50 kPa
c. 75 kPa
d. 100 kPa
38. A real gas will behave ideally at
a.
b.
c.
d.
low temperatures and low pressures
low temperatures and high pressures
high temperatures and low pressures
high temperatures and high pressures
39. All of the following statements are basic assumptions of the kinetic theory except:
a. gas molecules travel in a perfectly chaotic motion
b. gas molecules in an ideal gas have no volume
c. gas molecules in an ideal gas do not exert attractive forces
d. collisions between particles are perfectly elastic
e. the kinetic energy of the gas is proportional to the temperature
40. At which temperature would He have the greatest kinetic energy?
a. 25oC
b. 37oC
c. 273 K
d. 298 K
41. How many total moles of KNO3 must be dissolved in water to make 1.5 liters of a 2.0 M solution?
a. 0.50 mol
b. 2.0 mol
c. 3.0 mol
d. 1.3 mol
c. AgBr
d. Al(OH)3
c. CoSO4
d. CaCO3
42. Which of the following is soluble?
a. CaCl2
b. BaSO4
43. Which of the following is insoluble?
a. NaCl
b. KNO3
44. The concentration of a solution in moles per liter is called its _________________.
a. molar mass
b. molarity
c. volume mass
d. ppm
45. How many grams are needed to prepare 500 mL of a 2.50 M NaCl solution?
a. 1.25 g
b. 58.5g
c. 73.1 g
d. 146 g
46. What is the total amount of heat required to vaporize 1.00 g of H2O(l) at 100oC and 1 atm.
∆Hvap= 40.7kJ/mol
a. 4.18 J
b. 334 J
c. 373 J
d. 2261 J
47.-50. The potential energy diagram for the reaction of
carbon and hydrogen is shown to the right with the
reaction below:
2 C(s) + 2 H2(g) + 80.4 kJ 
C2H4(g)
d
47. Which section of the diagram represents the ∆Hrxn?
b
48. Which section represents the activation energy?
c
49. Calculate the amount of energy required to form 2.0
moles of C2H4.
a. +40.2 kJ
c. +160.8 kJ
b. +80.4 kJ
d. -80.4 kJ
a
.
50. The diagram represents.
a. an exothermic reaction where energy is released
b. an exothermic reaction where energy is absorbed
c. an endothermic reaction where energy is released
d. an endothermic reaction where energy is absorbed
51. What is required for a chemical reaction to occur?
a. standard temperature and pressure
b. a catalyst added to the reaction system
c. effective collisions between reactant particles
d. an equal number of moles of reactants and products
52. Increasing the temperature of a liquid solvent when dissolving a solid solute
a. always increases the rate at which a solid solute dissolves
b. often increases the amount of solid solute that can dissolve
c. both a and b
d. neither a and b
53. Which equation represents the radioactive decay of
a.
226
88 Ra
b.
226
88 Ra
→
222
86 Rn
→
226
89 Ac
4
2
+ He
+
0
1 e
226
88 Ra
by an alpha emission?
c.
226
88 Ra
d.
226
88 Ra
→
226
87 Fr
→
225
88 Ra
+
0
1
+
1
0n
e
54 Beta particles are:
a. rapidly moving helium nuclei
b. electromagnetic radiation more energetic than X-rays
c. electrons which move at tremendous speeds
d. particles with the same mass as an electron but has a positive charge
55. Given the diagram representing a reaction:
Which phrase best describes this type of reaction and the overall energy change that occurs?
a. fission and energy is released
b. fission and energy is absorbed
253
99
Es + X →
56. Given the nuclear equation:
4
2
a. He
57. If
b.
0
1
e
c. fusion and energy is released
d. fusion and energy is absorbed
1
0n
+
256
101
Md which particle represents X?
c.
1
0n
d.
0
1
e
1
of an original sample of Kr-74 remains after 34.5 minutes, what is the half life of Kr-74?
8
a. 11.5 minutes
b. 23.0 minutes
c. 34.5 minutes
d. 46.0 minutes
58. Nuclear fusion
a. takes place in the sun
b. is when two smaller nuclei form a larger nuclei
c. produces nonradioactive products
d. all of the above
59. Iodine-131 has a half-life of 8 days. If the amount of iodine-131 in a sample is 64.0g, how much will
remain after 40 days?
a. 16.0 g
b. 8.0 g
c. 4.0 g
60. Which of the following is true concerning gamma radiation?
a. The mass number of the radioisotope decreases by four.
b. The atomic number of the radioisotope decreases by two.
c. The atomic number of the radioisotope increases by one.
d. Neither the mass number nor the atomic number changes.
d. 2.0 g