If 14.7 g of calctum is placed in 11.5 g of water, what mass of hydrogen gas is produced?

I’m guessing you mean calcium?

Start off with a balanced equation:

2Ca + 2H20 ➡️ 2CaOH + H2

This is a limiting reactant problem. Solve for the amount of H2 gas produced with respect to each reactant using the mole ratio. The reactant that produces the least amount of H2 has is the answer.

it is important to conserve water because there is very limited amount of freshwater here on earth and if we are not smart about how we use it we will only be runnning out of our supply faster than neccessarry.

the answer is b & c i believe : )