Question

Calculate the heat change in joules required to convert 500.0 g of steam to water at 100.0 degree Celsius and indicate whether heat was absorbed or released? The heat vaporization water is 2260J/g.

Answer 1

`1,130,000J`; released

Explanation:

`E = mL`

energy change needed = mass of water * specific latent heat of vaporisation

specific: energy needed to heat `1g` of water
vaporisation: from a liquid to a gas
latent: without changing the temperature

specific latent heat of vaporisation of water: `2260J//g`.

`E` is in joules `J`
`m` is in grams `g`
`L` is in joules per gram `J//g`

`E = 500g * 2260 J//g`

`= 1130000J`

the heat change in joules is `1,130,000J`

this energy is released.

in a liquid, there are more bonds between molecules. in a gas, there are much fewer.

making bonds releases energy, while breaking bonds absorbs it.

bonds are made when changing state from gas to liquid, so when steam changes to water, energy is released as bonds are made.