science chemistary

to verify the law of conservation of mass in a chemical reaction following chemical reaction were performed
(a) ferrous sulhpate crystals were heated in china dish
(b) carbon dioxide gas was paased through a lime water in a test tube
(c) lead nitrate solutions was added to sodium chloride solution in a sealed clonical flask
(d) zinc granules were added to dil hydrochloride solutions in a sealed clonical flask
****best tresults are like to obtained the reacttion******