math of chemistry review
Name: ____________________________________
Tuesday, May 20, 2008
1.
What is the molecular formula of a compound with the empirical formula PO
2 5 and a gram-molecular mass of 284 grams?
1. P2O5
3. P10O4
2. P5O2
4. P4O10
2.
Which substance has the same molecular and empirical formulas?
1. C 6H4
3. CH4
2. C 2H4
4. C6H12O6
3.
Vitamin C has an empirical formula of C3H4O3 and a molecular mass of 176. What is the molecular formula of Vitamin C?
1. C 3H4O3
3. C9H12O9
2. C 6H8O6
4. C10H8O3
4.
What is the empirical formula of the compound whose molecular formula is PO
4 10?
1. PO
3. P2O5
2. PO2
4. P8O20
5.
A compound has a gram formula mass of 56 grams per mole. What is the molecular formula for this compound?
1. CH2
3. C3H6
2. C 2H4
4. C4H8
6.
A compound has a molar mass of 90. grams per mole and the empirical formula CHO.
What is the molecular formula of this compound?
2
1. CH2O
3. C3H6O3
2. C 2H4O2
4. C4H8O4
math of chemistry review
7.
What is the total number of moles of atoms in one mole of (NH)
4 2SO4?
1. 10
2. 11
3. 14
4. 15
8.
.
What is the total number of atoms of oxygen in the formula Al(ClO)
3 3 6H2O?
1. 6
2. 9
3. 10
4. 15
9.
What is the percent by mass of oxygen in Fe2O3 (formula mass = 160)?
1. 16%
2. 30.%
3. 56%
4. 70.%
10.
What is the total number of moles of oxygen atoms present in one mole of Mg(ClO)
3 2?
1. 5
2. 2
3. 3
4. 6
11.
What is the total mass of oxygen in 1.00 mole of Al2(CrO4)3?
1. 192 g
2. 112 g
3. 64.0 g
4. 48.0 g
12.
Which quantity is represented by the symbol Ne?
1. 1 gram of neon
2. 1 liter of neon
3. 1 mole of neon
4. 1 atomic mass unit of neon
math of chemistry review
13.
What is the percent by mass of sulfur in sulfur dioxide?
1. 32
2. 33
3. 50
4. 67
14.
The percent by mass of water in BaCl2 . 2H2O (formula mass = 243) is equal to
1.
2.
3.
4.
15.
What is the gram formula mass of Ca3(PO4)2?
1. 135 g/mol
2. 215 g/mol
3. 278 g/mol
4. 310. g/mol
16.
One mole of which substance contains a total of 6.02 × 1023 atoms?
1. Li
3. O2
2. NH3
4. CO2
17.
A hydrate is a compound that includes water molecules within its crystal structure. During an experiment to determine the percent by mass of
water in a hydrated crystal, a student found the mass of the hydrated crystal to be 4.10 grams. After heating to constant mass, the mass was 3.70
grams. What is the percent by mass of water in this crystal?
1. 90.%
2. 11%
3. 9.8%
4. 0.40%
math of chemistry review
18.
What is the percent by mass of oxygen in propanal, CH3CH2CHO?
1. 10.0%
2. 27.6%
3. 38.1%
4. 62.1%
19.
Cylinder A contains 22.0 grams of CO2(g) and cylinder B contains N2(g). The volumes, pressures, and temperatures of the
two gases are indicated under each cylinder.
Figure 1
Base your answer to the question on the information and diagrams.
The total number of moles of CO2(g) in cylinder A is
mol
20.
In which compound is the percent composition by mass of chlorine equal to 42%?
1. HClO (gram-formula mass = 52 g/mol)
3. HClO3 (gram-formula mass = 84 g/mol)
2. HClO2 (gram-formula mass = 68 g/mol)
4. HClO4 (gram-formula mass = 100. g/mol)
math of chemistry review
21.
Base your answer to the question on the equation below, which represents an organic compound reacting with bromine.
Figure 2
What is the gram-formula mass of the product in this reaction? Round your answer to the nearest whole number.
Answer:
g/mol
math of chemistry review
22.
Base your answer to the question on the information below.
A student places a 2.50-gram sample of magnesium metal in a bottle and fits the bottle with a 2-hole stopper as shown in the
diagram. Hydrochloric acid is added to the bottle, causing a reaction. As the reaction proceeds, hydrogen gas travels through the
tubing to an inverted bottle filled with water, displacing some of the water in the bottle.
Figure 3
What is the correct numerical setup for calculating the number of moles of magnesium used in the experiment?
1. 24.3g × 2.5g = x mol
2.
3.
4.
math of chemistry review
23.
Base your answer to this question on the information below.
A hydrate is a compound that has water molecules within its crystal structure. The formula for the hydrate CuSO4 5H2O(s) shows
that there are five moles of water for every one mole of CuSO4(s). When CuSO4 5H2O(s) is heated, the water within the crystals
is released, as represented by the balanced equation below.
CuSO4 5H2O(s)
CuSO4(s) + 5H2O(g)
A student first masses an empty crucible (a heat-resistant container). The student then masses the crucible containing a sample of
CuSO4 5H2O(s). The student repeatedly heats and masses the crucible and its contents until the mass is constant. The student's
recorded experimental data and calculations are shown below.
Figure 4
Using the student's data, what is the correct numerical setup for calculating the percent composition by mass of water in the hydrate?
1.
2.
3.
4.
math of chemistry review
24.
Given the equation: __FeCl2 + __Na2CO3
__FeCO3 + __NaCl
When the equation is correctly balanced using the smallest whole numbers, the coefficient of NaCl is
1. 6
2. 2
3. 3
4. 4
25.
In the compound Al2O3, the ratio of aluminum to oxygen is?
1. 2 grams of aluminum to 3 grams of oxygen
2. 3 grams of aluminum to 2 grams of oxygen
3. 2 moles of aluminum to 3 moles of oxygen
4. 3 moles of aluminum to 2 moles of oxygen
26.
When the equation
__C8H16 + __O2
__CO2 + __H2O
is correctly balanced using the smallest whole number coefficient, the coefficient of O2 is
1. 1
2. 8
3. 12
4. 16
27.
Which equation illustrates conservation of mass?
1. H2 + Cl2
2. H2 + Cl2
3. H2 + O2
4. H2 + O2
HCl
2HCl
H2O
2H2O
28.
When the equation
__Al2(SO4)3 + __ZnCl2
__AlCl3 + __ZnSO4
is correctly balanced using the smallest whole number coefficients, the sum of the coefficients is
1. 9
2. 8
3. 5
4. 4
math of chemistry review
29.
Given the equation:
__Ca 2+ (aq) + __PO43- (aq)
__Ca 3(PO4)2(s)
When the equation is correctly balanced, the sum of the total charge of the reactants is
1. 0
2. +2
3. -3
4. +6
30.
When the equation
__Fe2O3(s) + __CO(g)
__Fe(l) + __CO2(g)
is correctly balanced using the smallest whole numbers, the coefficient of Fe(l) is
1. 1
2. 2
3. 3
4. 4
31.
Given the reaction: CH4(g) + 2O2(g)
CO2(g) + 2H2O(g)
How many moles of oxygen are needed for the complete combustion of 3.0 moles of CH(g)?
4
1. 6.0 moles
2. 2.0 moles
3. 3.0 moles
4. 4.0 moles
32.
Given the reaction: 2Al + 3H2SO4
3H2 + Al2(SO4)3
The total number of moles of H2SO4 needed to react completely with 5.0 moles of Al is
1. 2.5 moles
2. 5.0 moles
3. 7.5 moles
4. 9.0 moles
33.
Given the reaction: Ca + 2H2O
Ca(OH) 2 + H2
How many moles of H2O are needed to react completely with 2.0 moles of Ca?
1. 1.0 mole
2. 2.0 moles
3. 0.50 mole
4. 4.0 moles
math of chemistry review
34.
Given the unbalanced equation: N2(g) + H2(g) → NH3(g)
When the equation is balanced using the smallest whole-number coefficients, the ratio of moles of hydrogen consumed to moles of ammonia
produced is
1. 1:3
2. 2:3
3. 3:1
4. 3:2
35.
Given the incomplete equation: 2N2O5(g)
_____
Which set of products completes and balances the incomplete equation?
1. 2N2(g) + 3H2(g)
3. 4NO2(g) + O2(g)
2. 2N2(g) + 2O2(g)
4. 4NO(g) + 5O2(g)
36.
If an equation is balanced properly, both sides of the equation must have the same number of
1. atoms
2. coefficients
3. molecules
4. moles of molecules
37.
Given the reaction: 6 CO2 + 6 H2O → C2H12O6 + 6 O2
What is the total number of moles of water needed to make 2.5 moles of CH
2 12O6?
1. 2.5
2. 6.0
3. 12
4. 15
38.
Given the reaction: C6H12O6(s) + 6O2(g) → 6CO2(g) + 6H2(l)
How many moles of C6H12O6(s ) are needed to produce 24 moles of carbon dioxide?
1. 1.0 mole
2. 12 moles
3. 24 moles
4. 4.0 moles
math of chemistry review
39.
Given the reaction: 4NH3 + 5O2 → 4NO + 6H2 O
What is the total number of moles of NO produced when 1.0 mole of O2 is completely consumed?
1. 1.0 mole
2. 1.2 moles
3. 0.80 mole
4. 4.0 moles
40.
Given the equation: 2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(g)
How many moles of oxygen are required to react completely with 1.0 mole of CH
2 2?
1. 2.5
2. 2.0
3. 5.0
4. 10
41.
Given the reaction: PbCl2(aq) + Na2CrO4 (aq) → PbCrO4 (s) + 2 NaCl(aq)
What is the total number of moles of NaCl formed when 2 moles of NaCrO
2
4 react completely?
1. 1 mole
2. 2 moles
3. 3 moles
4. 4 moles
42.
What is conserved during a chemical reaction?
1. mass, only
2. charge, only
3. both mass and charge
4. neither mass nor charge
43.
Antacids can be used to neutralize excess stomach acid. Brand A antacid contains the acid neutralizing agent magnesium hydroxide, Mg(OH)2. It
reacts with HCl(aq) in the stomach, according to the following balanced equation:
If a person produces 0.050 mole of excess HCl in the stomach, how many moles of Mg(OH)2 are needed to neutralize this excess hydrochloric
acid?
mole(s)
math of chemistry review
44.
Figure 5
Base your answer to the question on the potential energy diagram and the equation.
If 682.2 kilojoules are absorbed, how many moles of C2H2(g) are produced?
mol
45.
Given the balanced equation:
4Al(s) + 3O2(g) → 2Al2O3(s)
What is the total number of moles of O2(g) that must react completely with 8.0 moles of Al(s) in order to form AlO
2 3(s)?
mol
46.
A sample of a compound contains 65.4 grams of zinc, 12.0 grams of carbon, and 48.0 grams of oxygen. What is the mole ratio of zinc to carbon to
oxygen in this compound?
1. 1:1:2
2. 1:1:3
3. 1:4:6
4. 5:1:4
math of chemistry review
47.
Given the balanced equation:
What is the total number of moles of CO2 formed when 20. moles of HCl is completely consumed?
1. 5.0 mol
2. 10. mol
3. 20. mol
4. 40. mol
48.
Base your answer to the question on the information below.
Propane is a fuel that is sold in rigid, pressurized cylinders. Most of the propane in a cylinder is liquid, with gas in the space above
the liquid level. When propane is released from the cylinder, the propane leaves the cylinder as a gas. Propane gas is used as a fuel
by mixing it with oxygen in the air and igniting the mixture, as represented by the balanced equation below.
C3H8(g) + 5O2(g)
3CO2(g) + 4H2O( ) + 2219.2 kJ
A small amount of methanethiol, which has a distinct odor, is added to the propane to help consumers detect a propane leak. In
methanethiol, the odor is caused by the thiol functional group (-SH). Methanethiol, CH3SH, has a structure that is very similar to
the structure of methanol.
Figure 6
Determine the total amount of energy released when 2.50 moles of propane is completely reacted with oxygen.
× 103 kJ
Answer:
49.
The temperature of a sample of a substance changes from 10°C to 20°C. By how many Kelvins does the temperature change?
1. 10
2. 20
3. 283
4. 293
50.
Which temperature represents absolute zero?
1. 0 K
2. 0°C
3. 273 K
4. 273°C
math of chemistry review
Answer Key for math of chemistry review
1. 4
2. 3
3. 2
4. 3
5. 4
6. 3
7. 4
8. 4
9. 2
10. 4
11. 1
12. 3
13. 3
14. 2
15. 4
16. 1
17. 3
18. 2
19. 0.500
20. 3
21. 202
22. 4
23. 4
24. 2
25. 3
26. 3
27. 2
28. 1
29. 1
30. 2
31. 1
32. 3
33. 4
34. 4
35. 3
36. 1
37. 4
38. 4
39. 3
40. 1
41. 4
42. 3
43. 0.025
44. 3
45. 6
46. 2
47. 2
48. 5.5
49. 1
50. 1