Iwould like to know if this question is correct. if is not correct how can i solve it?

Calcium hydride (cah2) reacts with water to form hydrogen gas: cah2(s) + 2h2o(l) → ca(oh)2(aq) + 2h2(g) how many grams of cah2 are needed to generate 45.0 l of h2 gas at a pressure of 0.995 atm and a temperature of 32 °c?

How many moles of al3+ ions are in 1.25 moles of al2o3

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?