Assignment

Part 1: Identifying Types of Reactions

1. Classification of chemical reactions(2016-2017)

1. Matching: Match the following statements to one of the five types of reactions it best describes. Place the letters from the right column in the blocks on the left column.

- Two compounds react to form two different compounds.

- Oxygen combines with a hydrocarbon to form water and carbon dioxide.

- A compound reacts with an element to form a new compound and a different element.

- One reactant is broken down into two or more products.

- Two or more reactants combine to form one product.

A. Combustion

B. Decomposition

C. Synthesis (Combination)

D. Single replacement

E. Double replacement

2. Review and Practice: Balance the 10 chemical equations below (labeled A-J). (Some equations may only need coefficients of 1 so they appear balanced without anything added. You may put in the 1's if it helps you.)In the space to the right, classify the reaction as a synthesis,decomposition, single replacement, double replacement, or combustion reaction.

Reaction(you must balance each - don't change subscripts)   Type of Reaction

A. Mercury (I) Oxide forms mercury and oxygen.

_____ Hg₂O → _____ Hg + _____ O₂         _____

B. Cesium nitrate and potassium chloride react to produce cesium chloride and potassium nitrate.

_____ CsNO₃ + _____ KCl → _____ CsCl + _____ KNO₃    _____

C. Hexose (a type of sugar)burns in oxygen to produce water andcarbon dioxide.

_____ C₆H₁₂O₆ + _____ O₂ → _____ H₂O + _____ CO₂     _____

D. Magnesiumhydrogen carbonate is heated to producemagnesium carbonate and carbon dioxide andwater.

_____ Mg(HCO₃)₂ → _____ MgCO₃ + _____ CO₂ + _____ H₂O      _____

E. Pentane burns in oxygen to formcarbon dioxide and water.

_____ C₅H₁₂ + _____ O₂ → _____ CO₂ + _____ H₂O      _____

F. Calcium chloride and sodium sulfate produce calcium sulfate and sodium chloride.

_____ CaCl₂ + _____ Na₂SO₄ → _____ CaSO₄ + _____ NaCl    _____

G. Water and selenium trioxide react to produce selenic acid.

_____ H₂O + _____ SeO₃ → _____ H₂SeO₄       _____

H. Lithium iodide and bromine react to produce lithium bromide and iodine.

_____ LiI + _____ Br₂ → _____ LiBr + _____ I₂       _____

I. Calcium and hydrochloric acid produce calcium chloride and hydrogen gas.

_____ Ca + _____ HCl  → _____ CaCl₂ + _____ H₂      

J. Aluminum and copper (II) chloride produces aluminum chloride and copper.

_____ Al + _____ CuCl₂ → _____ AlCl₃ + _____ Cu      _____

Part 2: Stoichiometry Worksheet

Directions: You are strongly encouraged to print out this worksheet and work with paper&pencil and a calculator for these problems. Then, either scan in your completed worksheet or record your answers on this sheet and attach to it the drop box. You must show work for credit. There are 10 questions. SHOW THE SET-UP OF YOUR SOLUTION.

Example Problem 1. Use this balanced equation: 2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O.

Ex. How many grams of Water are produced when 10 grams of C₂H₆ is burned?

Set up the problem to go from the starting value to the ending value (what is given to what is needed).

Notice that the answer is 18 grams

Did you calculate? Did you get the right answer?

Use the following equation to answer questions 1-3: 2 C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O

1. How many moles of H₂O are produced when 2 moles of C₄H₁₀ are burned?

2. How many moles of Oxygen are needed to completely burn 2 moles C₄H₁₀?

3. How moles of CO₂ are produced when 2 moles C₄H₁₀ are completely burned?

Use the following equation to answer questions 4 & 5: 6 HCl + 2 Al  → 2 AlCl₃ + 3 H₂

4. How many moles of Aluminum are needed to produce 4 moles of AlCl₃?

5. How many moles of HCl are needed to use up 1 mole of Al?

Use this equation to answer questions 6 & 7:  2 C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O

6. How many moles of O₂ are needed when 16 moles of C₄H₁₀react?

7. How many moles of CO₂ are produced when 6.0 moles of C₄H₁₀ react?

Use this equation to answer question 8. 2 K + Br₂ → 2 KBr

8. How many moles of KBr are produced from 4.50 g of K?

Use the following balanced equation to answer 9 & 10.  2 H₂ + O₂ → 2 H₂O

9. How many grams of H₂O are produced when 8.0 grams of O₂ react?

10. How many moles of hydrogen (H₂) are needed to react with8.0 g of O₂?

Part 3: Stoichiometry and Limiting Reagents

Answer the following 15 questions.

1. Stoichiometry problems use all of the following, except one. Which one is NOT involved in stoichiometry?

a. mass of reactants or products

b. number of moles of reactants or products

c. amount of time it takes for a reaction to occur

d. a balanced equation must be used to solve stoichiometry problems

2. When the lesson pages talk about a mole ratio between two substances, what does that mean? Where do the numbers for the mole ratio come from?

3. One mole of Aluminum may be represented as 1 mol or _____ grams or _____ atoms.

4. Short essay question. Why is a balanced chemical equation needed to solve a stoichiometry problem?

5. Consider the reaction of combining hydrogen and nitrogen to produce ammonia.

The balanced equation is: 3H₂ + N₂ → 2NH₃

a. What is the mole ratio of hydrogen to nitrogen?

b. What is the mole ratio of hydrogen to ammonia?

c. What is the mole ratio of nitrogen to ammonia?

6. Consider the equation HCl + Al  → AlCl₃ + H₂.

a. Is this equation balanced?

b. Balance it. _ HCl + _ Al  → _ AlCl₃ + _ H₂

7. Use the balanced equation in #6b above. How many moles of hydrogen would be produced if you used 12 moles of HCl and enough Al to completely react?

8. In your own words, explain one of the methods used, (either from MrHunyady's video explanations, or the other method from the stoichiometry lesson) of how to find the amount of grams of a product from a given amount of moles of a reactant? This is an essay question. Please use an example to show how it works.

9. Explain what we mean by a limiting reagent. Use an everyday example to show what this means.

10. Suppose you are going to make sandwiches that contain 2 pieces of bread, 2 slices of ham, 3 slices of turkey, 2 leaves of lettuce and 2 pieces of cheese. If you have a total of 60 pieces of bread, 40 slices of ham, 30 slices of turkey, 50 leaves of lettuce and 20 pieces of cheese, how many sandwiches can you make?

11. In the sandwich problem above, how many pieces of ham would be left over after making all the sandwiches you could?

12. What is the limiting reagent (or ingredient) in this sandwich problem? (Is there more than one?)

13. Describe, in your own words, what is meant be each of these terms:

a. actual yield

b. theoretical yield

c. percent yield

14. Why would chemists not get a 100% yield on a reaction they run in a laboratory?

15. If a student calculates that he should get exactly 400.0 g of a certain product but in the lab, he only gets 285 g, what is the percent yield for the reaction?