Question

A chemist adds of a sodium carbonate solution to a reaction flask. Calculate the mass in grams of sodium carbonate the chemist has added to the flask. Be sure your answer has the correct number of significant digits.

Answer 1

The question is incomplete, here is the complete question:

A chemist adds 180.0 mL of a 1.42 M sodium carbonate solution to a reaction flask. Calculate the mass in grams of sodium carbonate the chemist has added to the flask. Be sure your answer has the correct number of significant digits.

Answer: The mass of sodium carbonate that must be added are 40.9 grams

Explanation:

To calculate the mass of solute, we use the equation used to calculate the molarity of solution:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}$

Molar mass of sodium carbonate = 106 g/mol

Molarity of solution = 1.42 M

Volume of solution = 180.0 mL

Putting values in above equation, we get:

$1.42mol/L=\frac{\text{Mass of sodium carbonate}\times 1000}{160g/mol\times 180}\\\\\text{Mass of sodium carbonate}=\frac{160\times 1.42\times 180}{1000}=40.9g$

Hence, the mass of sodium carbonate that must be added are 40.9 grams