Question

Calculate the amount of heat energy required to convert 55.0 g of water at 62.5°C to steam at 124.0°C. (Cwater = 4.18 J/g°C; Csteam = 2.02 J/g°C; molar heat of vaporization of liquid water = 4.07 ✕ 104 J/mol)

Answer 1

Answer:

= 135,647.65 Joules or 135.65 kJ

Explanation:

Heat require to raise the temperature of 55 g water from 62.5°C  to 124.0°C will be calculated in steps;

Step 1; heat required to raise water from 62.5°C to 100 °C

Heat = 55 g × 4.18 J/g°C × (100 -62.5)

        = 8,621.25 Joules

Step 2; Heat required to convert water to steam without change in temperature;

Heat = moles × Molar Latent heat of vaporization.

        = (55g / 18 g/mol)× 4.07 ✕ 104 J/mol

        = 12.436 × 10^4 Joules

Step 3: Heat required to raise the temperature of steam from 100°C to 124 °C.

Heat = mass × specific heat capacity × ΔT

        = 55 g × 2.02 J/g°C × (124-100)

        = 2,666.4 Joules

Therefore; total amount of heat required is;

 = 8,621.25 J + 124360 J + 2,666.4 J

= 135,647.65 Joules or 135.65 kJ