A mass of 50g of calcium carbonate is heated, releasing carbon dioxide and calcium oxide. Which of these recorded masses of products is possible, according to the Law of
Conservation of Mass?

Select one:
23g of carbon dioxide, 50g of calcium oxide
29g of calcium oxide, 21g of carbon dioxide

50g of calcium oxide, 50g of carbon dioxide
50g of calcium oxide, 1g of recorded carbon dioxide

For a research project, a student decided to test the effect of the lead(ii) ion (pb2+) on the ability of salmon eggs to hatch. this ion was obtainable from the water‐soluble salt, lead(ii) nitrate, which the student decided to make by the following reaction. pbo(s) + 2 hno3(aq) → pb(no3)2(aq) + h2o losses of product for various reasons were expected, and a yield of 86.0% was expected. in order to have 5.00 g of product at this yield, how many grams of pbo should be reacted? (assume that sufficient nitric acid, hno3, would be used.)