1.) Use the changes in oxidation number to identify which atoms are oxidized and which are reduced in each reaction. a.) 2Na(s) + Cl2(g) --> 2NaCl(s)

Na --> Na+1 is oxidized Cl2 --> Cl- is reduced

b.) 2HNO3(aq) + 6HI(aq) --> 2NO(g) + 3I2(s) + 4H2O(l)

N+5 --> N+2 is reduced I-1 --> I2 is oxidized

c.) 3H2S(g) + 2HNO3(aq) --> 3S(s) + 2NO(g) + 4H2O(l)

d.) 2PbSO4(s) + 2H2O(l) --> Pb(s) + PbO2(s) + H2SO4(aq)

Which statement describes the appearance of a temperature-vs.-time graph? a horizontal line shows that the temperature increases at a constant rate over time. a vertical line shows that the temperature decreases at a constant rate over time. horizontal lines where the temperature is constant during phase changes connect upward-sloping lines where the temperature increases. horizontal lines where the temperature increases are connected by upward-sloping lines where the temperature is constant for each phase.

For which one of the following reactions is the value of δh° rxn equal to δh° f for the product? a. 2 h2 (g) + o2 (g) → 2 h2o (l) b. n2 (g) + o2 (g) → 2 no (g) c. 2 h2 (g) + o2 (g) → 2 h2o (g) d. h2o (l) + 1/2 o2 (g) → h2o2 (l) e. none of the above

1. combine iron and copper (ii) sulfate solution. (hint: iron will form the iron (iii) ion) fe + cuso4 → 2. combine lead (ii) nitrate and potassium iodide solutions. pb(no3)2+ kl → 3. combine magnesium metal and hydrochloric acid solution. mg + hcl → 4. electrolysis (splitting) of water. h2o → 5. burning magnesium. mg + o2 →