Question

30,000 J of heat are added to 23.0 kg of steel to reach a final temperature of 140
°C. What was the initial temperature of the steel? (csteel =490J/kg * °C)
1. First find AT using the formula q=mcAT
2. Rearrange to solve for initial temperature using AT=Tfinal -Tinital


I need help quickly!!!!

Answer 1

The initial temperature is 137.34 °C.

Explanation:

As the specific heat formula says that the heat energy required is directly proportional to the mass and change in temperature of the system.

Q = mcΔT

So, here the mass m is given as 23 kg, the specific heat of steel is given as c = 490 J/kg°C and the initial temperature is required to find with the final temperature being 140 °C. Also the heat energy required is 30,000 J.

ΔT =$\frac{Q}{mc}$

ΔT =$\frac{30000}{23 \times 490} = \frac{30000}{11270} =2.66$

Since the difference in temperature is 2.66, then the initial temperature will be

Final temperature - Initial temperature = Change in temperature

140-Initial temperature = 2.66

Initial temperature = 140-2.66 = 137.34 °C

Thus, the initial temperature is 137.34 °C.