m(CuO) = 5. 6 g
m(CaH2) - ?
n(CuO) = 5. 6 / 80 = 0. 07 mol
0. 07 mol x mol
CuO + H2 = Cu + H2O
1 mol 1 mol
1:0. 07 = 1:x
x = 0. 07 ( n(H2) = 0. 07 mol )
y mol 0. 07 mol
CaH2 = Ca + H2
1 mol 1 mol
1:0. 07 = 1:y
y = 0. 07
m(CaH2) = 0. 07 * 42 = 2. 94 g
: 2. 94 g .