1. Chemistry Daily 10’s Week 12

2. 1 1. In a chemical reaction a. the mass of the reactants equals the mass of the products. b. the mass of the products is greater than the mass of reactants. c. the number of atoms in the reactants and products must change. d. energy as heat must be added to the reactants.

3. 2. In writing a chemical equation that produces hydrogen gas, the correct representation of hydrogen gas is a. H. b. 2H. c. H 2. d. OH.

4. 2 1. Which of the following is a formula equation for the formation of carbon dioxide from carbon and oxygen? a. Carbon plus oxygen yields carbon dioxide. b. C + O 2  CO 2 c. CO 2  C + O 2 d. 2C + O  CO 2

5. 2. A chemical formula written over the arrow in a chemical equation signifies a. a by-product. b. the formation of a gas. c. a catalyst for the reaction. d. an impurity.

6. 3 1. Which coefficients correctly balance the formula equation NH 4 NO 2 (s)  N 2 (g) + H 2 O(l)? a. 1, 2, 2 b. 1, 1, 2 c. 2, 1, 1 d. 2, 2, 2

7. 2. In what kind of reaction does one element replace a similar element in a compound? a. displacement reaction b. combustion c. decomposition reaction d. ionic reaction

8. 4 1. In what kind of reaction do the ions of two compounds exchange places in aqueous solution to form two new compounds? a. synthesis reaction b. double-displacement reaction c. decomposition reaction d. combustion reaction

9. 2. The reaction represented by the equation 2KClO 3 (s)  2KCl(s) + 3O 2 (g) is a(n) a. synthesis reaction. b. decomposition reaction. c. combustion reaction. d. ionic reaction.

10. 5 1. If chlorine gas is produced by halogen replacement, the other halogen in the reaction must be a. bromine. b. iodine. c. astatine. d. fluorine.

11. 2. Which reaction does not occur? a. 2HF(aq) + Cl 2 (g)  F 2 (g) + 2HCl(aq) b. 2Na(s) + ZnF 2 (aq)  2NaF(aq) + Zn(s) c. Fe(s) + CuCl 2 (aq)  FeCl 2 (aq) + Cu(s) d. 2HCl(aq) + Mg(s)  MgCl 2 (aq) + H 2 (g)

12. Answers & Standards 1.1 – a – sc2b 1.2 – c – sc2a 2.1 - b – sc2a 2.2 - c – sc2a 3.1 - b – sc2a 3.2 - a – sc2a 4.1 - b – sc2a 4.2 - b – sc2a 5.1 - d – sc2a 5.2 - a – sc2a