масова частка карбону в речовині дорівнює 78.6%Гідрогену-6.38%.все iншу Оксиген.Густина речовини-4ю196%

дано

m(ppa  KOH) = 300 g

W(KOH) = 20%

m(ppa H3PO4) = 300 g

W(H3PO4)= 20%

m(K3PO4)-?

m(H2O)-?

m(KOH) = m(ppa KOH) * W(KOH) / 100% = 300 * 20% / 100% = 60 g

M(KOH) = 56 g/mol

n(KOH) = m(KOH) / M(KOH) = 60 / 56 = 1.07 mol

m(H3PO4) = m(ppa H3PO4) * W(H3PO4) / 100% = 300 * 20% / 100% = 60 g

M(H3PO4) = 98 g/mol

n(H3PO4) = m(H3PO4) / M(H3PO4) = 60 / 98 = 0.61 mol

n(KOH) > n(H3PO4)

H3PO4+3KOH-->K3PO4+3H2O

n(H3PO4) = n(K3PO4) = 0.61 mol

M(K3PO4) = 212 g/mol

m(K3PO4) = n(K3PO4) * M(K3PO4) = 0.61 * 212 = 129.32 g

n(H3PO4) = 3n(H2O)

n(H2O)  = 3 * 0.61 = 1.83 mol

M(H2O) = 18 g/mol

m(H2O) = n(H2O) * M(H2O) = 1.83 * 18 = 32.94 g

ответ 129.32 г , 32.94 г