Question

A heater in a hot water tank gives off 20,000 KJ per hour. The initial temperature of 450 kg of water in the tank is 8.0 degrees * C the tank is heated for 90 minutes , determine the final temperature of the water.

Answer 1

The final temperature of the water is 23.92°C.

Step-by-step explanation:

Given that,

A heater in a hot water tank gives off 20,000 kJ per hour.

For 1 hour or 60 minutes, heat is 20,000 kJ

For 90 minutes,

`Q=(20000)/(60)* 90\\Q=30000\ kJ`

Mass, m = 450 kg or 450000 grams

Initial temperature,
`T_i=8^(\circ) C`

We need to find the final temperature of the water. We know that the specific heat capacity of water is 4.186 J/g- °C

Heat is given by :

`Q=mc\Delta T\\\\Q=mc(T_f-T_i)\\\\T_f=(Q)/(mc)+T_i\\\\T_f=(30000* 10^3)/(450000* 4.186)+8\\\\T_f=23.92^(\circ) C`

Hence, the final temperature of the water is 23.92°C.