If the total mass of the products of a reaction is 90 gram, what was the total mass of the reactants

Ineed ! it’s science and it’s due tomorrow!

Select the most likely product for this reaction: koh(aq) + co2(g) – ? k2co3(aq) + h2o(1) k(s) + h2(g) + o2(g) k(s) + co3(9) +h2

Why is the melting of ice a physical change ?