Here is a new set of chemistry problems that you can use as drill and/or reviewer questions.
Percent Composition Problems
| 1. | Cd(NO3)2.4H2O |
| Answer: H = 2.61% O = 51.87% Cd = 36.44% N = 9.08% |
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| 2. | NaHCO3 |
| Answer: Na = 27.37% H = 1.2% C = 14.3% O = 57.14% |
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| 3. | Co(NO3)2 |
| Answer: Co = 32.21% N = 15.31% O = 52.47% |
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| 4. | A laboratory sample was found to contain 68.05 % BaCO3. Compute the amount of C present in 0.67 g of the sample. |
| Answer: 0.03 g |
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| 5. | A laboratory sample was found to contain 33.56 % KIO3. Compute the amount of I present in 9.91 g of the sample. |
| Answer: 1.97 g |
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| 6. | A laboratory sample was found to contain 44.72 % PbSO4. Compute the amount of O present in 1.56 g of the sample. |
| Answer: 0.15 g |
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| 7. | A sample mixture containing ZnCl2 has 4.83 % Zn. Calculate the percentage of ZnCl2 in the sample. |
| Answer: 10.07 % |
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| 8. | A sample mixture containing CuCO3 has 5.19 % C. Calculate the percentage of CuCO3 in the sample. |
| Answer: 53.39 % |
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| 9. | Calculate the amount in g of C contained in 5.01 g of CaC4H4O6. |
| Answer: 1.28 g of C |
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| 10. | Calculate the amount in g of Na contained in 7.43 g of Na2CO3.H2O. |
| Answer: 2.75 g of Na |
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Solute Concentration Problems
| 1. | Calculate the weight of a 17% by weight CaCl2 solution that will contain 7.61 g CaCl2. |
| Answer: 44.76 g solution |
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| 2. | Fuming hydrochloric acid has a density of 1.19 g/mL and has 37% HCl by weight. What is the mass of HCl in 55 mL of this acid? |
| Answer: 24.22 g HCl |
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| 3. | 4.69 g of HCl is needed to be obtained from fuming hydrochloric acid (density 1.19 g/mL) which has 37% HCl by weight. Calculate the volume of fuming hydrochloric acid needed. |
| Answer: 10.65 mL fuming hydrochloric acid |
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| 4. | 235 mL of a solution with a concentration of 8 M NaClO4 is needed to be diluted in order to prepare a solution having a concentration of 4 M NaClO4. What must be the final volume of the diluted solution? |
| Answer: 470 mL |
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| 5. | How many g of ZnCl2 is needed to prepare a 182 mL of a solution containing 3.46 g ZnCl2 per mL? |
| Answer: 629.72 g ZnCl2 |
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| 6. | Calculate the weight of a 8% by weight KI solution that will contain 3.46 g KI. |
| Answer: 43.25 g solution |
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| 7. | Concentrated sulfuric acid has a density of 1.84 g/mL and has 97% H2SO4 by weight. What is the mass of H2SO4 in 144 mL of this acid? |
| Answer: 257.01 g H2SO4 |
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| 8. | 137 mL of a solution with a concentration of 5 M Cu2S is needed to be diluted in order to prepare a solution having a concentration of 1 M Cu2S. What must be the final volume of the diluted solution? |
| Answer: 685 mL |
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| 9. | 4.69 g of HCl is needed to be obtained from fuming hydrochloric acid (density 1.19 g/mL) which has 37% HCl by weight. Calculate the volume of fuming hydrochloric acid needed. |
| Answer: 10.65 mL fuming hydrochloric acid |
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| 10. | 101 mL of a solution with a concentration of 8.24 g K2S2O5 per mL is needed to be diluted in order to prepare a solution having a concentration of 6.45 g K2S2O5 per mL. What must be the final volume of the diluted solution? |
| Answer: 129.03 mL |
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Stoichiometry Problems
| 1. | Based on the following equation: Cu2S + O2 --> 2Cu + SO2, calculate the number of mol of Cu2S required to yield 4.02 mol of Cu. |
| Answer: 2.01 mol of Cu2S |
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| 2. | Given the equation: 2KClO3 --> 2KCl + 3O2, how many mol of KClO3 will be needed to produce 7.23 mol of O2? |
| Answer: 4.82 mol of KClO3 |
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| 3. | According to the equation: CaCO3 --> CaO + CO2, calculate the mass of CaCO3 required so that 4.29 mol of CaO will be produced. |
| Answer: 429.38 g of CaCO3 |
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| 4. | Based on the following equation: 2C2H6 + 7O2 --> 4CO2 + 6H2O, how many g of C2H6 will be needed to produce 4.87 mol of H2O? |
| Answer: 48.81 g of C2H6 |
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| 5. | Based on the following equation: CaO + 3C --> CaC2 + CO, how many g of C is required so that 1.2 g of CaC2 is produced? |
| Answer: 0.67 g of C |
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| 6. | Given the equation: 4KClO3 --> 3KClO4 + KCl, calculate the weight of KClO3 necessary to produce 8.37 g of KClO4. |
| Answer: 9.87 g of KClO3 |
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| 7. | Given the equation: 2KClO3 --> 2KCl + 3O2, calculate the amount of O2 that can be produced from the decomposition of 7.83 g of KClO3. |
| Answer: 3.07 g of O2 |
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| 8. | According to the equation: 4KClO3 --> 3KClO4 + KCl, calculate the weight of KClO3 necessary to produce 2.86 g of KCl. |
| Answer: 18.81 g of KClO3 |
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| 9. | Based on the following equation: 5C + 2SO2 --> CS2 + 4CO, how many g of C will be needed to produce 3.07 mol of CO? |
| Answer: 46.09 g of C |
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| 10. | Based on the following equation: CaCO3 + 2HCl --> CO2 + CaCl2 + H2O, how many mol of CaCO3 is needed to produce 1.57 g of CO2? |
| Answer: 0.04 mol of CaCO3 |
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