High School

How much heat is required to change 1.47 kg of H₂O at 68.0°C to steam at 144°C?

The specific latent heat of vaporization of water is 2,257,000 J kg⁻¹.

The specific heat capacity of water is 4,186 J kg⁻¹K⁻¹, and the specific heat capacity of steam is 1,996 J kg⁻¹K⁻¹.

Answer :

Final answer:

To change 1.47 kg of H₂O at 68.0°C to steam at 144°C, a total of 3,495,988 J of heat is required.

Explanation:

To calculate the amount of heat required to change 1.47 kg of H₂O from 68.0°C to steam at 144°C, we need to consider two steps: heating the water to its boiling point and then vaporizing it.

First, we calculate the heat required to raise the temperature of the water from 68.0°C to its boiling point, 100°C, using the specific heat capacity of water: Q = m * C * ΔT = (1.47 kg) * (4186 J/kg/K) * (100°C - 68.0°C) = 176,698 J.

Next, we calculate the heat required to vaporize the water at 100°C using the latent heat of vaporization of water: Qv = m * Lv = (1.47 kg) * (2,257,000 J/kg) = 3,319,290 J.

Now, to calculate the total heat required, we sum up the two values: Q_total = Q + Qv = 176,698 J + 3,319,290 J = 3,495,988 J.