1)
дано
m(J₂) = 2.54 g
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m(AgJ)=?
2AgJ--t-->2Ag+J₂
M(J₂) = 127 * 2 = 254 g/mol
n(J₂)= m(J₂) / M(J₂) = 2.54 / 254 = 0.01 mol
2n(AgJ) = n(J₂)
n(AgJ) = 0.01 * 2 = 0.02 mol
M(AgJ) = 235 g/mol
m(AgJ) = n(AgJ) * M(AgJ) = 0.02 * 235 = 4.7 g
ответ 4.7 г
2)
дано
m(Fe2O3) = 55 g
m пр. (Fe) = 35 g
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m теор.(Fe)- ?
W(Fe)- ?
2Fe2O3-->4Fe+3O2
M(Fe2O3) = 160 g/mol
n(Fe2O3) = m(Fe2O3) / M(Fe2O3) = 55 / 160 = 0.34375 mol
2n(Fe2O3) = 4n(Fe)
n(Fe) = 4 * 0.34375 / 2 = 0.6875 mol
M(Fe) = 56 g/mol
m теор.(Fe) = n(Fe) * M(Fe) = 0.6875 * 56 = 38.5 g
W(Fe) = m пр.(Fe) / m теор.(Fe) * 100% = 35 / 38.5 * 100% = 90.9%
ответ 38.5 г , 90.9%