Question

How much heat is required to raise the temperature of 27.8 g27.8 g of water from −55 °C−55 °C to 145 °C?

Answer 1

Answer

89.4 kJ

Explanation

i) Heat required to raise the temperature of ice from -55°C to 0℃(q₁)

q₁ = m × ∆T × C_s

= 27.8g × 55°C × 2.108J/g℃

= 3223.1J

ii) Heat required to melt ice at 0℃ (q₂)

q₂ = m × ∆H_vap

= 27.8g × 333.6J/g

= 9274.1J

iii) Heat required to raise the temperature of liquid water from 0℃ to 100℃ (q₃)

q₃ = m × ∆T × C_s

= 27.8g × 100℃ × 4.184J/g℃

= 11632J

iv) Heat required to vaporise liquid water at 100℃ (q₄)

q₄ = m × ∆H_vap

= 27.8 × 2257J/g

= 62745J

v) Heat required to raise the temperature of gaseous water from 100℃ to 145℃(q₅)

q₅ = m ×∆T × C_s

= 27.8g × 45℃ × 1.996J/g℃

= 2497J

vi) Total heat required(q)

q = q₁ + q₂ + q₃+ q₄ + q₅

= 3223.1J + 9274.1J + 11632J + 62745J + 2497J

= 89371J

= 89.4kJ