2NiO(s)→2Ni(s)+O2(g)

Question

If O2 is collected over water at 40.0C and a total pressure of 739mmHg , what volume of gas will be collected for the complete reaction of 24.18g of NiO?

Answer 1

mols NiO = 24.18 g NiO/molar mass NiO.
Convert mols NiO to mols O2 using the coefficients in the balanced equation.
Using PV = nRT convert n = mols to volume at the stated conditions.
For pressure, use 739-vapor pressure H2O at 40 C.