Question

How much heat would be evolved (released) if 50.0g of steam is at 114°C was cooled and condensed into water at 87°C?

Answer 1

Answer:

Q ≈ 1 x 10⁵ joules (1 sig. fig. based on 50g sample given)

Explanation:

Three heat transitions need be considered. Cooling the steam to 100°C, condensing the steam to water and cooling the water from 100°C to 87°C.

Total Heat exchange (Q) = ∑ heat transitions

Q = (m·c·ΔT)steam + (m·ΔH)condensation + (m·c·ΔT)water cooling

= (50g x 0.48j/g·°C x 14°C) + (50g x 2259j/g) + (50g x 4.184j/g·°C)

= 24j + 112,950j + 209.2j

= 113,183.2j ≈ 1 x 10⁵ joules (1 sig. fig. based on 50g sample given)