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.

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.

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:

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:

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

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"