How much heat (in joule) is required to raise the temperature of `205 g` of water from `21.2^(@)C` to `91.4^(@)C`. Specific heate of water is `4.18 J g^(-1) .^(@)C^(-1)`
Strategy : The specific heat of a substance is the amount of heat required to raise the temperature of `1g` of the substance by `1^(@C`.
Thus
Specific heat
`= (("Amount of heat in joules"))/(("Mass of substance in grams")("Temperature change in" .^(@)C))`
Rearrangement gives.
Amount of heat `(q) =` Mass of substance `(m) xx` Specific heat
`(c ) xx` Temperature change `(Delta T)`

Explanation

Accroding to
`q = mc Delta T`
`= (205 g) (4.18 J g^(-1) .^(@)C^(-1)) (91.4^(@)C - 21.2^(@)C)`