Question

If 3.70 mol calcium carbide (CaC2) reacts with an excess of water, how many moles of acetylene (C2H2) will be produced?

Answer 1

Write the equation and balance it.
CaC2 + 2H2O ==> C2H2 + Ca(OH)2

Now use the coefficients to convert mols CaC2 to mols of anything in the equation.
3.70 mol CaC2 x (1 mol C2H2/1 mol CaC2) = ? mol C2H2