Question

A chemist adds 255.0mL of a 1.27M sodium carbonate Na2CO3 solution to a reaction flask. Calculate the mass in grams of sodium carbonate the chemist has added to the flask.

Answer 1

Answer: The mass in grams of sodium carbonate is 34.3 g

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

$Molarity=\frac{n\times 1000}{V_s}$

where,

n = moles of solute

$V_s$ = volume of solution in ml

moles of $Na_2CO_3$ = $\frac{\text {given mass}}{\text {Molar mass}}=\frac{xg}{106g/mol}$

Now put all the given values in the formula of molarity, we get

$1.27=\frac{xg\times 1000}{106g/mol\times 255.0 ml}$

$x=34.3g$

Therefore, the mass in grams of sodium carbonate is 34.3 g