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ArbitrLikvidat [17]
3 years ago
7

How much heat is transferred in the process of completely melting a 1.6kg block of ice starting at -15 degrees Celsius? Is this

process endothermic or exothermic?
Chemistry
1 answer:
mixas84 [53]3 years ago
4 0

Answer:

  • a) Heat = 590 kJ

  • b) Endothermic

Explanation:

<em>Endothermi</em>c processes absorb energy. The final state contains more energy than the initial state.

Since ice absorbs heat energy <em>in the process of completely melting</em> this is an <em>endothermic</em> process.

The process involves two stages: 1) heating the ice up to the melting point, which is 0ºC, and 2) melting the ice.

1. Heating the ice from -15ºC to 0ºC

a) Formula: Q = m×C×ΔT

  • m = 1.6 kg
  • C = 2.108 kJ/kg.ºC (specific heat of ice)
  • ΔT = 15ºC

b) Calculations:

  • Q = m×C×ΔT = 1.6 kg × 2.108 kJ/kg.ºC  × 15ºC = 50.592 kJ

2. Melting the ice at 0ºC

a) Formula:  L = m × ΔHf

  • m = 1.6 kg
  • ΔHf = 334 kJ/kg (latent heat of fussion)

b) Calculations

  •    L = m × ΔHf = 1.6 kg × 334 kJ/kg = 534.40 kJ

<u />

<u>2. Total heat</u>

<u />

  • 50.592 kJ + 534.40 kJ = 584.992 kJ ≈ 590 kJ (rounded to 2 significant figures)
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