2. Chemical Formulas, Equations, and Reactions Review

3. 2ZnS + 3O 2 → 2ZnO + 2SO 2 In the equation above… A. What is the coefficient of sulfur dioxide? B. What is the subscript of the oxygen molecule? C. Where are the new substances located? 2 2 To the right of the arrow

4. Which of the following formulas contain the same number of hydrogen atoms? A. CH ₃ COOH B. (NH ₄ ) ₂ CO ₃ C. Ca(C ₂ H ₃ O ₂ ) ₂ D. N ₂ H ₄ A and D

5. In a chemical equation what does the __ mean? A.  ? B. Coefficient? C. Subscript? In a chemical equation what does the __ mean? A.  ? B. Coefficient? C. Subscript? Yields # of Molecules # of Atoms

6. Amount of Reactants Amount of Products Law of Conservation of Mass Which equation shows this Law? A. 2H 2 + O 2  H 2 O B. Na + Cl 2  2NaCl C. 4Fe + 3O 2  2Fe 2 O 3 D. 4C + 2H 2  CH 4 Which equation shows this Law? A. 2H 2 + O 2  H 2 O B. Na + Cl 2  2NaCl C. 4Fe + 3O 2  2Fe 2 O 3 D. 4C + 2H 2  CH 4 C. 4Fe + 3O 2  2Fe 2 O 3 It is balanced.

7. Chemical or Physical Change? Chemical or Physical Change? Chemical, a precipitate is forming.

8. In the chemical equation how would you classify the reactants, the product? N ₂ + 2O ₂ → 2NO ₂ Element + Element  Compound

9. What is the formula? Fe 2 O 3 Mg Cl MgCl 2

10. Which of the equations shows CaCl 2 forming when calcium reacts with chlorine? A. CaCl 2  Ca + Cl 2 B. Ca  Cl 2 + CaCl 2 C. CaCl 2 + Ca  Cl 2 D. Cl 2 + Ca  CaCl 2

11. How do you know that a chemical reaction (change) has taken place? Give 3 ways! 1. Gas is given off (bubbles) 2. A precipitate is formed 3. A temperature change has occurred 4. A color change 5. An odor change

12. Which set of coefficients would balance the equation? _Al +_O 2  _Al 2 O 3 A. 2, 3, 3 B. 4, 3, 2 C. 4, 2, 3 D. 2, 3, 2 _Al +_O 2  _Al 2 O 3 A. 2, 3, 3 B. 4, 3, 2 C. 4, 2, 3 D. 2, 3, 2 B. 4, 3, 2

13. Draw a cube model demonstrating a balanced equation for ferric oxide 4Fe + 3O ₂  2Fe ₂ O ₃ Fe OO OO OO O O O OOO + 

14. FormulaName CuSO 4 Copper Sulfate FeOFerrous Oxide H 2 SO 4 Sulfuric Acid NaOHSodium Hydroxide What does FeO stand for? Ferrous Oxide

15. How many atoms in a molecule of Sodium Hydroxide? NameFormula CuSO 4 Copper Sulfate FeOFerrous Oxide H 2 SO 4 Sulfuric Acid NaOHSodium Hydroxide 3

16. Before Chemical Reaction After Chemical Reaction Exothermic

17. 4H 3 PO 3  3H 3 PO 4 + PH 3 2Mg + CO 2 -> 2MgO + C

18. How many atoms are represented in the product of this equation? P ₄ O ₁₀ + 6H ₂ O  4H ₃ PO ₄ 32

19. If 17 grams of Na is combined with 9 grams of Chlorine, how much table salt (NaCl) would be formed? 26g

20. Which substance in the following equation is classified as an element? 2CH ₄ + 3O ₂ → 2CO + 4H ₂ O 3O ₂