For both questions, show your work or explain how you determined the formulas by giving specific values used in calculations.
1. Calculate the mass of 5.3 moles of chloric acid . Explain the process or show your work by including all values used to determine the answer.
2. The following data was collected when a reaction was performed experimentally in the laboratory.
Reaction Data
Reactants Products
Fe2O3 Al Al2O3 Fe
Starting Amount in Reaction 3 moles 5 moles ? ?
Determine the maximum amount of Fe that was produced during the experiment. Explain how you determined this amount.
3. 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?
4. 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. Part 1. A chemist reacted 15.0 liters of F2 gas with NaCl in the laboratory to form Cl2 and NaF. Use the ideal gas law equation to determine the mass of NaCl that reacted with F2 at 280. K and 1.50 atm.
F2 + 2NaCl → Cl2 + 2NaF
Explain how you would determine the mass of sodium chloride that can react with the same volume of fluorine gas at STP.
6. In an experiment, calcium carbonate reacted with different volumes of hydrochloric acid in water. One of the products formed during the experiment was carbon dioxide. The time taken for 0.89 mL of carbon dioxide to form was recorded. A partial record of the experiment is shown.
Experimental Record
Flask Mass of
Calcium Carbonate Volume of
HCl Volume of
Water Time
1 4.0 g 25 mL 0 mL 11.2 seconds
2 4.0 g 20 mL 5 mL
3 4.0 g 15 mL 10 mL
4 4.0 g 10 mL 15 mL
Based on your knowledge of factors that affect the rates of chemical reactions, predict the trend in the last column of the experimental record. Use complete sentences to explain the trend you predicted. You do not have to determine exact values for time; just describe the trend you would expect and why it occurs.
