Calculate the grams of water needed to react completely with 2.0 moles of calcium causing the reaction below

1 Ca + 2 H20 ➡ 1 Ca(OH)2 + 1 H2

The covalent compound acetylene, which is the fuel of the oxyacetylene torch used by welders, has the molecular formula c2h2. the covalent compound benzene, a commercial solvent, has the molecular formula c6h6 each of these covalent compounds contains carbon and hydrogen atoms in a one-to-one ratio. would it be correct to write the chemical formulas of each as ch? explain.

Can someone me with questions 15 to 17 plz.

Modern weaponry has increased the number of deaths in wars and violent conflicts.