А)
дано
m(P2O5) = 71 g
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m(H3PO4)-?
P2O5+3H2O-->2H3PO4
M(P2O5) = 142 g/mol
n(P2O5) = m / M = 71 / 142 = 0.5 mol
n(P2O5) = 2n(H3PO4)
n(H3PO4) = 2*0.5 = 1 mol
M(H3PO4)= 98 g/mol
m(H3PO4) = n*M = 1*98 = 98 g
ответ 98 г
Б) дано
m(СO2) = 88 g
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m(CO2)-?
CO2+H2O-->H2CO3
M(CO2 ) = 44 g/mol
n(CO2) = m / M = 88 / 44 = 2 mol
n(CO2) = n(H2CO3) = 2 mol
M(H2CO3)= 62 g/mol
m(H2CO3) = n*M = 2*62 = 124 g
ответ 124 г
в)
дано
V(CO2) = 89.6 L
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m(H2CO3)-?
CO2+H2O-->H2CO3
n(CO2) = V / Vm= 89.6 / 22.4 = 4 mol
n(CO2) = n(H2CO3) = 4 mol
M(H2CO3)= 62 g/mol
m(H3CO3) = n*M = 4*62 = 248 g
ответ 248 г
г)
дано
m(B2O3) = 100 g
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m(H3BO3)-?
B2O3+3H2O-->2H3BO3
M(B2O3) = 70 g/mol
n(B2O3) = m / M = 100 / 70 = 1.43 mol
n(B2O3) = 2n(H3BO3)
n(H3BO3) = 2*1.43 = 2.86 mol
M(H3BO3)= 62 g/mol
m(H3BO3) = n*M = 2.86*62 = 177.32 g
ответ 177.32 г
д)
дано
m(SO3) = 320 g
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m(H2SO4)-?
SO3+H2O-->H2SO4
M(SO3) = 80 g/mol
n(SO3) = m / M = 320 / 80 = 4 mol
n(SO3) = n(H2SO4) = 4 mol
M(H2SO4)= 98 g/mol
m(H2SO4) = n*M = 4*98 = 392 g
ответ 392 г