Answer:
Percent of sodium nitrate is 82.13%
Explanation:
[tex]NaNO_{3}\rightarrow NaNO_{2}+\frac{1}{2}O_{2}[/tex]
Number of moles of a compound is the ratio of mass of the compound to molar mass of the compound.
Molar mass of [tex]NaNO_{2}[/tex] = 68.9953 g/mol
Molar mass of [tex]NaNO_{3}[/tex] = 84.9947 g/mol
So, 0.2820 g [tex]NaNO_{2}[/tex] = [tex]\frac{0.2820}{68.9953}[/tex] moles of [tex]NaNO_{2}[/tex] = 0.004087 moles of [tex]NaNO_{2}[/tex]
Above equation suggests, 1 mol of [tex]NaNO_{2}[/tex] is formed from 1 mol of [tex]NaNO_{3}[/tex]
So, 0.004087 moles of [tex]NaNO_{2}[/tex] are formed from 0.004087 moles of [tex]NaNO_{3}[/tex]
So, mass of 0.004087 moles of [tex]NaNO_{3}[/tex] = [tex](0.004087\times 84.9947)g=0.3474g[/tex] [tex]NaNO_{3}[/tex]
% of [tex]NaNO_{3}[/tex] in sample = [tex]\frac{0.3474}{0.4230}\times 100[/tex]% = [tex]82.13[/tex]%
