Question

16. A kettle used at a building site is filled with 25 liters of water at 16 °C. The water is heated until it reaches 90 °C. Calculate the amount of heat required in kJ.

Answer 1

The Heat is
`Q = 7736.7 \ KJ`

Step-by-step explanation:

Generally from the question we are told that

The volume of the water is
`V = 25 L = (25)/(1000) = 0.025 \ m^3`

The initial temperature is
`T_i = 16^oC = 16 + 273 = 289 \ K`

The final temperature is
`T_f = 90^o C = 90 + 273 = 363 \ K`

Generally the heat required is mathematically represented as

`Q = m * c_w * (T_f - T_i)`

Here
`c_w` is the specific heat capacity of water with value
`c_w = 4182 J/(K kg)`

m is the mass of the water which is mathematically represented as

`m = \rho * V`

Here
`\rho` is the density of the water which has a value
`\rho = 1000 kg/m^3`

So

`m = 0.025 * 1000 = 25 kg`

So

`Q = 25 * 4182 * (363 - 289)`

=>
`Q = 7736700 \ J`

Converting to KJ

`Q = ( 7736700)/(1000)`

=>
`Q = 7736.7 \ KJ`