Chemistry 5 Fall 2001 Stoichiometry Problem Set. Name:

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1 Chemistry 5 Fall 2001 Stoichiometry Problem Set Name: Ground Rules: This problem set is open book, open notes. You can consult any book or your notes from class or reading while you are working on the problems. This problem set has no time limit. You can take as long as you need to complete it. You may stop working on the problem set and start again at a later time, provided you do not discuss the problems with anyone. This problem set is to be done independently. It is a violation of the Honor Principle to work on these problems with any other student or tutor. It is a violation of the Honor Principle to discuss the content of these problems with another student until everyone has completed the assignment on 10/8 or shortly thereafter. Significant figures will be included in points for each numerical problem. Point values for each question appear in parentheses in the margins It is vital that you show clear, readable calculations for each problem. If you make a mistake, you cannot receive partial credit without showing your work. If your work is not easily deciphered, you may not receive the maximum partial credit. This problem set is due at 10 a.m. Monday 10/8, at the beginning of Chem 5 class. If you have questions, please ask Prof. Hair. Please sign below when you are finished and ready to turn in the assignment. Your signature below means that you have upheld the Honor Principle in completing this assignment. Signature:

2 1. Iodine and fluorine form a series of compounds and two have the following compositions: Compound Mass % Iodine Mass % Fluorine Calculate the mass of fluorine the will combine with 1.00 g of iodine to form each compound. (3) Compound 1: (3) Compound 2: (2) Show that these two compounds satisfy the Law of Multiple Proportions. (Remember simple whole-number ratios) (4) What are the empirical formulas of these compounds? Show a calculation to support your answer or refer to your results above. Compound 1: Compound 2:

3 2. Which of the following samples contains the greatest mass of chlorine? Circle the (15) correct answer and show supporting calculations for full credit. 5.0 g Cl g NaClO mole KCl 30.0 g MgCl mole Cl 2

4 3. Titanium is a strong, lightweight, corrosion-resistant metal used in rockets, jet engines, and bicycle frames. It is prepared by the following reaction, between titanium (IV) chloride and liquid magnesium, at temperatures between 950 C and 1150 C. TiCl 4 (g) + Mg (l) Ti (s) + MgCl 2 (l) In an industrial process, g of TiCl4 react with g of Mg. (8) How much titanium metal can be produced, assuming the yield is 100%? (4) What is the percent yield of the reaction if g of titanium are produced?

5 4. A solution is prepared by adding ml of 1.00 M ZnCl 2 (aq) solution to ml (8) of a NaCl (aq) solution. What is the molar concentration of each of the ions in the final solution? Show calculations to support your results. [Cl ] = [Na+] = [Zn2+] =

6 5. Iron has 4 stable isotopes with masses and natural abundances, given below. (8) Symbol mass number isotopic mass abundance 54Fe % 56Fe % 57Fe % 58Fe % Calculate the molar mass of iron.

7 6. Balance the following chemical equations. (12) C 6 H 6 (l) + O 2 (g) CO 2 (g) + H 2 O (l) Al (s) + HCl (aq) AlCl 3 (aq) + H 2 (g) CaCl 2 (aq) + Na 2 CO 3 (aq) CaCO 3 (s) + NaCl (aq) Mg (s) + CO 2 (g) MgO(s) + C (s) Na 2 SO 4 (aq) + BaCl 2 (aq) BaSO 4 (s) + NaCl (aq) KOH (aq) + H 2 SO 4 (aq) K 2 SO 4 (aq) + H 2 O (l) (5) Now go back and label FIVE equations with one of the following labels: A/B for an acid/base reaction R for a redox reaction P for a precipitation reaction (8) Now go back and write a net ionic equation for FOUR of the above equations.

8 7. You are asked to analyze the content of an asprin tablet, which is expected to contain 0.32 g of acetlysalicylic acid, HC 9 H 7 O 4. You decide to titrate the acid in the asprin tablet with sodium hydroxide, NaOH, according to the titration reaction HC 9 H 7 O 4 (aq) + NaOH (aq) NaC 9 H 7 O 4 (aq) + H 2 O (3) In the above equation, label the acid, base, and salt. (2) Write the net ionic equation for the reaction. (7) If you want to have the volume of NaOH titrant needed for the analysis be about 25 ml, what concentration of NaOH will you need for your experiment?

9 8. The Claus reactions are used to generate elemental sulfur from hydrogen sulfide, in the two steps shown below 2 H 2 S + 3 O 2 2 SO H 2 O SO H 2 S Fe 2 O 3 (as catalyst) 3 S + 2 H 2 O (4) What mass of sulfur can be produced from 48.0 g of O 2? (4) How much H 2 S will be consumed in the two-step process, starting with 48.0 g of O 2?

AP Chemistry Honors Unit Chemistry #4 2 Unit 3. Types of Chemical Reactions & Solution Stoichiometry

HO AP Chemistry Honors Unit Chemistry #4 2 Unit 3 Chapter 4 Zumdahl & Zumdahl Types of Chemical Reactions & Solution Stoichiometry Students should be able to:! Predict to some extent whether a substance