Here's another set of chemistry reviewer questions.
Stoichiometry Problems
| 1. | Given the equation: 2C2H6 + 7O2 --> 4CO2 + 6H2O, how many g of C2H6 will be needed to produce 3.13 mol of CO2?
Answer: 47.06 g of C2H6 |
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| 2. | Based on the following equation: 2ZnS + 3O2 --> 2ZnO + 2SO2, how many mol of ZnS is needed to produce 7.95 g of ZnO? Answer: 0.1 mol of ZnS |
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| 3. |
Given the equation: 2KClO3 + 2KCl --> 3O2 + H2O, how many g of KCl is required so that 3.73 g of H2O is produced? Answer: 30.87 g of KCl |
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| 4. |
Given the equation: 2KClO3 --> 2KCl + 3O2, calculate the weight of KClO3 necessary to produce 1.57 g of KCl. Answer: 2.58 g of KClO3 |
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| 5. | Based on the following equation: 3KClO --> 2KCl + KClO3, calculate the amount of KClO3 that can be produced from the decomposition of 7.62 g of KClO. Answer: 3.44 g of KClO3
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Percent Composition Problems
| 1. | Calculate the percentage composition of AlCl3. Solution: Al = 20.24% Cl = 79.76% |
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| 2. | Calculate the amount of S contained in 2.88 g of FeSO4.H2O. Solution: 0.54 g of S |
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| 3. | Calculate the percentage composition of BaC2O4.2H2O. Solution: H = 1.54% O = 36.73% Ba = 52.54% C = 9.19% |
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| 4. | Calculate the amount of Ba contained in 3.76 g of BaI2. Solution: 1.32 g of Ba |
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| 5. | Determine the weight of KSCN that will contain 7.69 g of C. Solution: 62.22 g of KSCN |
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| 6. |
A laboratory sample was found to contain 92.06 % LiNO3. Compute the amount in g of Li present in 2.72 g of the sample. Solution: 0.25 g |
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| 7. | A laboratory sample was found to contain 18.83 % PbC2O4. Compute the amount in g of O present in 0.56 g of the sample. Solution: 0.023 g |
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| 8. | A sample mixture containing Ba(CH3COO)2 has 1.42 % O. Calculate the percentage of Ba(CH3COO)2 in the sample. Solution: 5.67 % |
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| 9. |
A sample mixture containing NH4HCO3 has 3.23 % C. Calculate the percentage of NH4HCO3 in the sample. Solution: 21.26 % |
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| 10. |
Determine the weight of Cd(NO3)2 that will contain 0.84 g of O. Solution: 2.07 g |
Limiting Reagent Problems
| 1. |
Based on the following equation: NaCl + AgNO3 --> AgCl + NaNO3, calculate the weight of AgCl which can be produced by the reaction of 7.45 g of NaCl with 7.48 g of AgNO3.Answer: AgNO3 is the limiting reagent; 6.31 g of AgCl can be produced. The weight of excess NaCl is 4.88 g. |
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| 2. | Given the balanced equation: 2SO2 + O2 --> 2SO3, calculate the weight of SO3 which can be produced by the reaction of 7.07 g of SO2 with 7.09 g of O2. Answer: SO2 is the limiting reagent; 8.84 g of SO3 can be produced. The weight of excess O2 is 5.32 g. |
Formula Calculation Problems
| 1. |
What is the formula weights of the following compounds: (a) KMnO4, (b) KI, (c) CoCl2, (d) Sr(OH)2, (e) (NH4)2S, (f) CdCl2.H2O, (g) B2O3. Answer: (a) 158.0339, (b) 166.0028, (c) 129.8392, (d) 121.6346, (e) 68.1366, (f) 201.3312, (g) 69.6182 |
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| 2. | Calculate the number of moles of AlCl3 that will contain 6.02 x 1023 atoms of Cl. Answer: 0.33 mol |
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| 3. | Calculate the number of moles of PbC2O4 that will contain 6.02 x 1023 atoms of O. Answer: 0.25 mol |
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| 4. |
How many number of O atoms are contained in 84.94 g of KNO3? Answer: 1.52 x 1024 atoms |
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| 5. | How many number of Na atoms are contained in 33.99 g of Na3PO4? Answer: 3.74 x 1023 atoms |
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| 6. | Determine the number of molecules of KBrO3 present in 36.77 g of KBrO3. Answer: 1.33 x 1023 molecules |
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| 7. | Determine the number of molecules of SbCl3 present in 60.83 g of SbCl3. Answer: 1.61 x 1023 molecules |
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| 8. | Calculate the weight in grams of 5.12 mol NaCl. Answer: 299.23 g |
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| 9. |
Calculate the weight in grams of 0.85 mol CdCl2.H2O. Answer: 171.13 g |
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| 10. |
Calculate the number of O atoms in 2.44 x 10-4 mol of KCH3COO. Answer: 2.94 x 1020 atoms |
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