1)
дано
V(O2) = 7.88 L
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m(O2)-?
N(O2)-?
Vm = 22.4 L/mol
M(O2) = 32 g/mol
m(O2) = M(O2) * V(O2) / Vm = 32*7.88 / 22.4 = 11.26 g
N(A) = 6.02*10^23 молекул
N(O2) = N(A) * V(O2) / Vm = 6.02*10^23 * 7.88 / 22.4 = 2.12*10^23 молекул
ответ 11.26 g, 2.12*10^23 молекул
2)
дано
N(CH4) = 120*10^23
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n(CH4)-?
V(CH4)-?
m(CH4)-?
n(CH4) = N(CH4) / N(A) = 120*10^23 / 6.02*10^23 = 20 mol
V(CH4) = n(CH4)*Vm = 20*22.4 = 448 L
M(CH4) = 16g/mol
m(CH4) = n*M = 20*16 = 320 g
ответ 20 mol, 448 L ,320 g