Question

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

Answer 1

This is a incomplete question.The complete question is:

A chemist adds 180.0 ml of a 1.77 mol/L of sodium thiosulfate solution to a reaction flask. Calculate the mass in grams of sodium thiosulfate the chemist has added to the flask. Be sure your answer has the correct number of significant digits.

Answer: 50.4 g

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Moles of solute}={\text{Molarity of the solution}}\times{\text{Volume of solution (in L)}}$     .....(1)

Molarity of sodium thiosulfate solution = 1.77 M

Volume of sodium thiosulfate solution = 180.0 mL = 0.1800 L

Putting values in equation 1, we get:

$\text{Moles of sodium thiosulfate}={1.77}\times{0.1800}=0.319moles$

Mass of sodium thiosulfate = $moles\times {\text {Molar mass}}=0.319moles\times 158.11g/mol=50.4g$

Thus 50.4 g of sodium thiosulfate the chemist has added to the flask.