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Chemistry Homework Help => AP Chemistry => Topic started by: gcs.redmond@gmail.com on January 19, 2026, 04:33:41 PM

Title: Unit 6-Thermodynamics - question on heating and cooling curve for water
Post by: gcs.redmond@gmail.com on January 19, 2026, 04:33:41 PM
How do I approach this kind of problem?Screenshot 2026-01-19 133223.png
Title: Re: Unit 6 - Thermodynamics - Heating/cooling curves Question
Post by: uma on January 20, 2026, 08:56:29 AM
heating curve of water.png
 
Step 1: Identify the path (state changes + temperature changes)

You are going from:H2O(𝑠)at 0∘C  →H2O(g) at 100 ∘C

That requires three stages:

1) Melt ice at 0°C → liquid at 0°C (fusion) B to C in heating curve)
    q1 = m ΔH0 fusion ( m is the mass of water)

2) Heat liquid water 0°C → 100°C (temperature rise from C to D in heating curve)
q2 = mcΔt (m is mass of water)

3) Vaporize liquid at 100°C → steam at 100°C (vaporization)
q3 = m Δ 𝐻 vap �

Total amount of heat needed = q1 + q2 + q3