WorksheetsModule 5: Stoichiometry Review
Total questions: 54
Worksheet time: 42mins
One mole of silver has a mass of 107.9 grams. Approximately how many atoms of silver are present in one mole of silver? (5.01)
107 atoms
108 atoms
6 x 1023 atoms
53 x 1023 atoms
One mole of copper has a mass of 63.5 grams. Approximately how many atoms of copper are present in one mole of copper? (5.01)
63 atoms
64 atoms
32 x 1023 atoms
6 x 1023 atoms
One mole of zinc has a mass of 65.4 grams. Approximately how many atoms of zinc are present in one mole of zinc? (5.01)
32 x 1023 atoms
6 x 1023 atoms
66 atoms
65 atoms
Which of the following best defines the molar mass of a substance? (5.01)
Mass, in grams, of each particle of the substance
Total mass, in grams, of 100 particles of the substance
Mass, in grams, of the nucleus of the substance's atoms
Total mass, in grams, of all the particles in one mole of the substance
Which of the following best defines Avogadro's number? (5.01)
Mass, in grams, of each particle of the substance
Number of particles in one mole of a pure substance
Mass, in grams, of the nucleus of the substance's atoms
Total mass, in grams, of all the particles in one mole of the substance
Which of the following best defines one mole of a substance? (5.01)
Mass, in grams, of each particle of the substance
Mass, in grams, of the nucleus of the substance's atoms
Amount of substance present in one atom of the substance
Amount of substance present in Avogadro's number of particles of the substance
How many atoms of K are present in 195.49 grams of K? (5.01)
3.0110 x 1024
6.0220 x 1024
1.1772 x 1026
4.5797 x 1027
How many atoms of Mg are present in 97.22 grams of Mg?(5.01)
6.022 x 1023
2.408 x 1024
4.818 x 1024
5.855 x 1025
How many atoms of Ca are present in 80.156 grams of Ca? (5.01)
1.2044 x 1024
2.4088 x 1024
4.8270 x 1025
1.9346 x 1027
Which formula can be used to calculate the molar mass of water (H2O)? (5.02)
2 x molar mass of H + 2 x molar mass of O
molar mass of H + 2 x molar mass of O
2 x molar mass of H + molar mass of O
molar mass of H + molar mass of O
Which formula can be used to calculate the molar mass of ammonia (NH3)? (5.02)
molar mass of N + molar mass of H
3 x molar mass of N + molar mass of H
molar mass of N + 3 x molar mass of H
3 x molar mass of N + 3 x molar mass of H
Which formula can be used to calculate the molar mass of hydrogen peroxide (H2O2)? (5.02)
molar mass of H + molar mass of O
2 x molar mass of H + molar mass of O
molar mass of H + 2 x molar mass of O
2 x molar mass of H + 2 x molar mass of O
How many moles of Ca(OH)2 are present in 370.47 grams of Ca(OH)2? (5.02)
2
3
5
6
How many moles of Ca(OH)2 are present in 370.47 grams of Ca(OH)2? (5.02)
2
3
5
6
How many moles of MgCO3 are present in 252.939 grams of MgCO3? (5.02)
2
3
5
6
Which pair of compounds has the same empirical formula? (5.03)
CH and C2H2
C2H6 and CH
C3H8 and C3H
C2H2 and C2H
Which pair of compounds has the same empirical formula? (5.03)
C2H6 and CH
CH3 and C2H6
C2H2 and C2H
C3H8 and C3H
Which pair of compounds has the same empirical formula? (5.03)
C4H10 and C6H
C4H10 and C2H5
C2H2 and C2H
C3H8 and C3H
What is the percentage composition of each element in hydrogen peroxide, H2O2? (5.03)
7.01% H and 92.99% O
7.22% H and 92.78% O
6.32% H and 93.68% O
5.88% H and 94.12% O
What is the percentage composition of each element in dinitrogen monoxide, N2O? (5.03)
58.32% N; 41.68% O
60.55% N; 39.45% O
63.64% N; 36.36% O
62.66% N; 37.34% O
What is the percentage composition of each element in ammonia, NH3? (5.03)
82.35% N; 17.65% H
80.55% N; 19.45% H
79.46% N; 20.54% H
78.57% N; 21.43% H
Determine the empirical formula of a compound containing 40.6 grams of carbon, 5.1 grams of hydrogen, and 54.2 grams of oxygen.
In an experiment, the molar mass of the compound was determined to be 118.084 g/mol. What is the molecular formula of the compound?
For both questions, show your work or explain how you determined the formulas by giving specific values used in calculations. (5.03)
Determine the empirical formula of a compound containing 47.37 grams of carbon, 10.59 grams of hydrogen, and 42.04 grams of oxygen.
In an experiment, the molar mass of the compound was determined to be 228.276 g/mol. What is the molecular formula of the compound?
For both questions, show your work or explain how you determined the formulas by giving specific values used in calculations. (5.03)
Determine the empirical formula of a compound containing 48.38 grams of carbon, 6.74 grams of hydrogen, and 53.5 grams of oxygen.
In an experiment, the molar mass of the compound was determined to be 180.15 g/mol. What is the molecular formula of the compound?
For both questions, show your work or explain how you determined the formulas by giving specific values used in calculations. (5.03)
Which of the following is necessary to do a complete stoichiometric calculation? (5.04)
Add the nuclear masses of the products.
Divide the nuclear masses of the reactants.
Write the complete balanced chemical equation.
Write the number of atoms in 1 mole of the product.
Which of the following is necessary to do a complete stoichiometric calculation? (5.04)
Write the mole ratio.
Add the nuclear masses of the products.
Divide the nuclear masses of the reactants.
Write the number of atoms in one mole of the product.
Which of the following is an incorrect step to do a complete stoichiometric calculation? (5.04)
Write the mole ratio.
Write the dimensional analysis.
Write the balanced chemical equation.
Write the nuclear masses of the products.
The following reaction shows sodium hydroxide reacting with sulfuric acid.
4NaOH + 2H2SO4 → 2Na2SO4 + 4H2O
How many grams of Na2SO4 are produced from 10.0 grams of NaOH?
(Molar mass of Na = 22.989 g/mol, O = 15.999 g/mol, H = 1.008 g/mol, S = 32.065 g/mol)
(5.04)
17.8 grams
19.2 grams
35.5 grams
38.5 grams
The following reaction shows sodium carbonate reacting with calcium hydroxide.
Na2CO3 + Ca(OH)2 → 2NaOH + CaCO3
How many grams of NaOH are produced from 20.0 grams of Na2CO3?
(Molar mass of Na = 22.989 g/mol, C = 12.01 g/mol, O = 15.999 g/mol, Ca = 40.078 g/mol, H = 1.008 g/mol)
(5.04)
12.2 grams
15.1 grams
24.4 grams
30.2 grams
The following reaction shows calcium chloride reacting with silver nitrate.
CaCl2 + 2AgNO3 → 2AgCl + Ca(NO3)2
How many grams of AgCl are produced from 30.0 grams of CaCl2?
(Molar mass of Ca = 40.078 g/mol, Cl = 35.453 g/mol, O = 15.999 g/mol, Ag = 107.868 g/mol, N = 14.007 g/mol)
(5.04)
19.4 grams
38.8 grams
58.2 grams
77.5 grams
Read the given chemical reaction.
C2H6 + O2 → CO2 + H2O
How many moles of O2 are required to react completely with 3.2 moles of C2H6?
(5.04)
3.5 moles of O2
6.5 moles of O2
10.4 moles of O2
11.2 moles of O2
Read the given chemical reaction.
C2H6 + O2 → CO2 + H2O
How many moles of CO2 are produced during the complete combustion of 3.6 moles of C2H6?
(5.04)
1.8 moles
4.4 moles
7.2 moles
9.2 moles
Read the given chemical reaction.
C2H6 + O2 → CO2 + H2O
How many moles of H2O are produced during the complete combustion of 1.4 moles of C2H6?
(5.04)
2.8 moles
4.2 moles
5.6 moles
7.0 moles
Which of the following statements best describes a limiting reactant? (5.05)
The reactant that is used up the least
The reactant that is used up the most
The reactant that is used up before the others
The reactant that is leftover after the reaction
Which of the following is true for a limiting reactant? (5.05)
It is the reactant whose atoms remain unbalanced in the equation.
It is the reactant that produces a smaller amount of a product.
It is the reactant that is left over after the reaction stops.
It is the reactant that produces one mole of a product.
Which of the following is true for an excess reactant? (5.05)
It is the reactant whose atoms remain unbalanced in the equation.
It is the reactant that produces a smaller amount of a product.
It is the reactant that is left over after the reaction stops.
It is the reactant that produces one mole of a product.
How many moles of water are produced when 6.0 moles of hydrogen gas react with 2.5 moles of oxygen gas?
Balanced equation: 2H2 + O2 → 2H2O
(5.05)
2.5 moles of water
3.0 moles of water
5.0 moles of water
6.0 moles of water
How many moles of water are produced when 5 moles of hydrogen gas react with 2 moles of oxygen gas?
Balanced equation: 2H2 + O2 → 2H2O
(5.05)
2 moles of water
4 moles of water
5 moles of water
7 moles of water
How many moles of water are produced when 3.0 moles of hydrogen gas reacts with 1.8 moles of oxygen gas?
Balanced equation: 2H2 + O2 → 2H2O
(5.05)
3.0 moles of water
3.6 moles of water
5.3 moles of water
7.0 moles of water
A synthesis reaction takes place when carbon monoxide (CO) and hydrogen gas (H2) react to form methanol (CH3OH). How many grams of methanol are produced when 7.0 grams of carbon monoxide reacts with 2.5 grams of hydrogen gas?
(5.05)
7.0 grams
8.0 grams
15 grams
20 grams
A synthesis reaction takes place when carbon monoxide (CO) and hydrogen gas (H2) react to form methanol (CH3OH). How many grams of methanol are produced when 14 grams of carbon monoxide reacts with 1.5 grams of hydrogen gas?
(5.05)
6 grams
8 grams
12 grams
16 grams
A synthesis reaction takes place when carbon monoxide (CO) and hydrogen gas (H2) react to form methanol (CH3OH). How many grams of methanol are produced when 2.8 grams of carbon monoxide reacts with 0.50 grams of hydrogen gas?
(5.05)
3.2 grams
3.6 grams
4.0 grams
6.0 grams
A chemist wants to extract copper metal from copper chloride solution. The chemist places 0.50 grams of aluminum foil in a solution containing 0.75 grams of copper (II) chloride. A single replacement reaction takes place. Which statement explains the maximum amount of copper that the chemist can extract using this reaction?
Unbalanced equation: CuCl2 + Al → AlCl3 + Cu
(5.05)
Approximately 0.36 grams, because copper (II) chloride acts as a limiting reactant
Approximately 1.8 grams, because copper (II) chloride acts as a limiting reactant
Approximately 0.36 grams, because aluminum acts as a limiting reactant
Approximately 1.8 grams, because aluminum acts as a limiting reactant
A chemist wants to extract copper metal from copper chloride solution. The chemist places 0.25 grams of aluminum foil in a solution of 0.40 grams of copper (II) chloride. A single replacement reaction takes place. What are the likely observations when the reaction stops?
Unbalanced equation: CuCl2 + Al → AlCl3 + Cu
(5.05)
About 0.90 grams of copper is formed, and some aluminum is left in the reaction mixture.
About 0.20 grams of copper is formed, and some aluminum is left in the reaction mixture.
About 0.90 grams of copper is formed, and some copper chloride is left in the reaction mixture.
About 0.20 grams of copper is formed, and some copper chloride is left in the reaction mixture.
A chemist wants to extract copper metal from copper chloride solution. The chemist places 1.50 grams of aluminum foil in a solution of 14 grams of copper (II) chloride. A single replacement reaction takes place. What best explains the state of the reaction mixture after the reaction?
Unbalanced equation: CuCl2 + Al → AlCl3 + Cu
(5.05)
Less than 6.0 grams of copper is formed, and some aluminum is left in the reaction mixture.
More than 6.5 grams of copper is formed, and some aluminum is left in the reaction mixture.
Less than 6.0 grams of copper is formed, and some copper chloride is left in the reaction mixture.
More than 6.5 grams of copper is formed, and some copper chloride is left in the reaction mixture.
Which of the following statements best defines the actual yield of a reaction? (5.06)
The amount of product measured after a reaction
The ratio of measured yield over theoretical yield
The maximum amount of product that can be obtained
The ratio of measured yield over stoichiometric yield
Which of the following statements best defines the percentage yield of a reaction? (5.06)
The ratio of measured yield over actual yield
The amount of product measured after a reaction
The amount of measured yield over calculated yield
The maximum amount of product that can be obtained
Which of the following statements best defines the theoretical yield of a reaction? (5.06)
The ratio of measured yield over actual yield
The amount of product measured after a reaction
The ratio of measured yield over stoichiometric yield
The maximum amount of product that can be obtained
The actual yield of a product in a reaction was measured as 1.20 g. If the theoretical yield of the product for the reaction is 1.82 g, what is the percentage yield of the product? (5.06)
65.9%
67.2%
71.9%
73.3%
The actual yield of a product in a reaction was measured as 2.80 g. If the theoretical yield of the product for the reaction is 3.12 g, what is the percentage yield of the product? (5.06)
82.7%
85.2%
87.3%
89.7%
The actual yield of a product in a reaction was measured as 4.20 g. If the theoretical yield of the product for the reaction is 4.88 g, what is the percentage yield of the product? (5.06)
82.6%
84.2%
86.1%
88.0%
A chemist reacted 57.50 grams of sodium metal with an excess amount of chlorine gas. The chemical reaction that occurred is shown.
Na + Cl2 → NaCl
If the percentage yield of the reaction is 86%, what is the actual yield? Show your work, including the use of stoichiometric calculations and conversion factors. (5.06)
A chemist reacted 11.50 grams of sodium metal with an excess amount of chlorine gas. The chemical reaction that occurred is shown.
Na + Cl2 → NaCl
If the percentage yield of the reaction is 85%, what is the actual yield? Show your work including, the use of stoichiometric calculations and conversion factors.
A chemist reacted 17.25 grams of sodium metal with an excess amount of chlorine gas. The chemical reaction that occurred is shown.
Na + Cl2 → NaCl
If the percentage yield of the reaction is 88%, what is the actual yield? Show your work, including the use of stoichiometric calculations and conversion factors.
