Calculate the mass fractions of all elements in the substances: P2O5 Na2SO4 K3PS4 Ca (NO3) 2.

| March 22, 2021 | education

We use the following formula.
W (e-ta) = n * Ar (e-ta) / Mr (in-va) * 100%,
where n is the number of atoms of an element in a molecule,
Ar – the relative atomic mass of the element (in the periodic table),
Mr is the relative molecular weight of the substance.
We calculate for P2O5.
M (P2O5) = 2 * 31 + 16 * 5 = 62 + 80 = 142 g / mol.
W (P) = 2 * 31/142 * 100% = 43.7%.
W (O) = 5 * 16/142 * 100% = 56.3%.
Calculating for Na2SO4.
M (Na2SO4) = 23 * 2 + 32 + 16 * 4 = 46 + 32 + 64 = 142 g / mol.
W (Na) = 2 * 23/142 * 100% = 32.4%.
W (S) = 32/142 * 100% = 22.5%.
W (O) = 4 * 16/142 * 100% = 45.1%.
We calculate for K3PO4.
M (K3PO4) = 3 * 39 + 31 + 4 * 16 = 212 g / mol.
W (K) = 3 * 39/212 * 100% = 55.2%.
W (P) = 31/212 * 100% = 14.6%.
W (O) = 4 * 16/212 * 100% = 30.2%.
We calculate for Ca (NO3) 2.
M (Ca (NO3) 2) = 40 + 14 * 2 + 16 * 6 = 164 g / mol.
W (Ca) = 40/164 * 100% = 24.4%.
W (N) = 2 * 14/164 * 100% = 17.1%.
W (O) = 16 * 6/164 * 100% = 58.5%.



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