A70.0 ml sample of water is heated to its boiling point. how much heat is required to vaporize it? (assume a density of 1.00 g/ml.)

Explanation:

As density is the amount of mass divided by volume of the substance.

Mathematically,     Density =

It is given that volume is 70.0 ml and density is 1.00 g/ml. Therefore, mass of the given substance will be as follows.

                Density =

                 1.00 g/ml =

                        mass = 70.0 g

As we known that heat of vaporization of water is 2260 J/g for 1 g of a substance. Therefore, heat of vaporization of water for 70.0 g will be as follows.

                       = 158200 J

or,                     = 158.2 kJ                (as 1 kJ = 1000 J)

Thus, we can conclude that 158.2 kJ heat is required to vaporize given sample of water.