Question

A chemist prepares a solution by dissolving 3.166 g of NaNO3 in enough water to make 200 mL of solution. What molar concentration of sodium nitrate should appear on the label?
Answer in units of M.

Answer 1

0.185 M is the molar concentration of sodium nitrate should appear on the label.

Explanation:

Data given:

mass of NaNO3 = 3.166 grams

atomic mass of NaNO3 = 84.99 grams/mole

volume of the solution = 200 ml  or 0.2 litres

molar concentration of sodium nitrate solution = ?

first number of moles of sodium nitrate is calculated as:

number of moles = $\frac{mass}{atomic mass of 1 mole}$

number of moles = $\frac{3.166}{85}$

number of moles = 0.037 moles

molarity = $\frac{number of moles}{\volume in litres}$

putting the values in the equation:

molarity =  $\frac{0.037}{0.2}$

molarity = 0.185

Molar concentration of the sodium nitrate solution made with 3.166 grams of NaNO3 in 200 ml solution is 0.185 M