answer is B value of approximation
solving
The heat of vaporization for water is 40.7 kJ/mol, which means that it takes 40.7 kJ of energy to convert 1 mole of water from a liquid to a gas phase.
The energy required to boil the water is given as 63.8 kJ.
We can set up a proportion using these values:
40.7 kJ/1 mol = 63.8 kJ/x mol
To solve for x (the number of moles of water), we can cross-multiply and solve the equation:
40.7 kJ * x mol = 63.8 kJ * 1 mol
x mol = (63.8 kJ * 1 mol) / 40.7 kJ
x mol ≈ 1.57 mol
Since we know the molar mass of water is approximately 18.015 g/mol, we can convert moles to grams:
1.57 mol * 18.015 g/mol ≈ 28.29 g
Therefore, the mass of the sample of water is approximately 28.29 grams.