High School

Lead has a specific heat capacity of approximately 128 J/kg·K. How much energy is required to raise the temperature of a 3 kg piece of lead from 40°C to 72°C? Express your answer in kilojoules.

Answer :

Final answer:

The energy required to raise the temperature of a 3 kg piece of lead from 40°C to 72°C is 12.288 kilojoules.

Explanation:

The student is asking how much energy is required to raise the temperature of a 3 kg piece of lead from 40°C to 72°C. To calculate this, we can use the formula:

Q = mcΔT,

where Q is the energy in joules, m is the mass in kilograms, c is the specific heat capacity, and ΔT is the change in temperature in degrees Celsius.

Given:

  • m = 3 kg
  • c = 128 J/kg°C
  • ΔT = 72°C - 40°C = 32°C

Plugging in these values:

Q = 3 kg × 128 J/kg°C × 32°C

Q = 12288 J

Since 1 kilojoule (kJ) is equal to 1000 joules (J), we divide the result by 1000 to convert it:

Q = 12.288 kJ

Therefore, the energy required to raise the temperature of the 3 kg piece of lead by 32°C is 12.288 kJ.