The specific heat of aluminum is approximately 900 J/kg°C. If the temperature of a 5 kg specimen needs to be raised from 30°C to 1000°C, the amount of heat required will be equal to Select one: a) - 4365 kJ b) - 4365 Btu c) - 4365W d) - None of the above

a) 4365 kJ

Explanation:

In any thermodynamic system, any heat change is accompanied by the change in temperature. The relation between heat released/gained in a system and the temperature is:

Q=mcΔT

where,

Q is the amount of heat absorbed or released

m is the mass

ΔT is the change in temperature

c is called the specific heat.

Specific heat is defined as heat gained by 1 unit mass of any sample to raise the temperature of the sample by 1 °Celsius.

Thus, from the question:

Mass of aluminum = 5 kg

Final temperature = 1000°C

Initial temperature = 30°C

ΔT = (1000 - 30) °C = 970°C

Specific heat of aluminum = 900 J/kg°C

Thus, Amount of heat required:

Q = 5 kg*900 J/kg°C*970°C = 4365000 J

The conversion of J into kJ is shown below:

1 J = 10⁻³ kJ

Thus, Heat gained by aluminum = 4365000 * 10⁻³ J = 4365 kJ