дано
m(K) = 15 g
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m(H2)-?
V(H2)-?
2K+2HCL-->2KCL+H2
M(K) = 39 g/mol
n(K) = m(K) / M(K) = 15/39 = 0.38 mol
n(K) = n(H2) = 0.38 mol
M(H2) = 2 g/mol
m(H2) = n(K) * M(K) = 2*0.38 = 0.76 g
V(H2) = n(H2) * Vm = 0.38 * 22.4 = 8.512 L
ответ 0.76 г, 8.512 л