Explain why all of the values for moles (of NaOH and citric acid) are calculated to three significant figures.

The values given in the question were given in three significant figures.

Explanation:

When solving questions, it is important to ensure that results from calculations are given to the same number of significant figures as the values given in the question.

All values for moles of citric acid and NaOH are given to three significant figures because the values of mass in the question were also given to three significant figures.

"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"