A0.4230 g sample of impure sodium nitrate (contains sodium nitrate plus inert ingredients) was heated, converting all the sodium nitrate to 0.2820 g of sodium nitrite and oxygen gas. determine the percent of sodium nitrate in the original sample.

Percent of sodium nitrate is 82.13%

Explanation:

Number of moles of a compound is the ratio of mass of the compound to molar mass of the compound.

Molar mass of = 68.9953 g/mol

Molar mass of = 84.9947 g/mol

So, 0.2820 g = moles of    = 0.004087 moles of  

Above equation suggests, 1 mol of    is formed from 1 mol of  

So, 0.004087 moles of   are formed from 0.004087 moles of  

So, mass of 0.004087 moles of   =

% of  in sample = % = %

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

a electronegativity decreases beacuse the size of nucleus is bigger.