An aqueous solution is found to be 3.64% potassium nitrate by mass, how many grams of solution should i evaporate the water from to get it 18.7 g of potassium nitrate

513.74 g of solution

Explanation:

% Mass grams are defined as the grams that are dissolved in salt (in this case, it would be potassium nitrate) dissolved every 100 g of the solution. Having this information, you can calculate the amount of solution that has dissolved 18.7 g of potassium nitrate, which is what we want to obtain.

The relationship is:

3.64 g of potassium nitrate 100 g solution

18.7 g of potassium nitrate X = 513.74 g of solution

Calculation: 18.7g x 100g / 3.64g = 513.74 g of solution

So, I need 513.74 g of solution to get 18.7g of potassium nitrate by evaporating it.