1. classify calcium: a. s = homogeneous mixture/solution b. e = element c. c = compound d. he = heterogeneous mixture 2. classify pizza: a. he = heterogeneous mixture b. e = element c. c = compound d. s = homogeneous mixture/solution 3. classify carbon monoxide: a. he = heterogeneous mixture b. c = compound c. s = homogeneous mixture/solution d. e = element