Internal energy and energy transfers

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Question 6
Easy

A sample of substance X is heated from a solid state until it becomes a gas. The graph below shows how the temperature of substance X varies with time.

A graph showing temperature in °C on the vertical y-axis against time in seconds on the horizontal x-axis. The y-axis has labels from -40 to 100. The x-axis has labels from 0 to 450. The heating curve shows four sections marked A, B, C, and D: Section A goes from (0, -20) directly to (50, 10). Section B is a horizontal line at 10 °C from 50 to 150 seconds. Section C goes from (150, 10) directly to (250, 80). Section D is a horizontal line at 80 °C from 250 to 400 seconds.

a.

Which part of the graph (A, B, C, or D) shows when substance X is boiling?

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b.

What happens to the kinetic energy of the particles as the temperature of substance X increases during section C?

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c.

Calculate the thermal energy needed to vaporize 0.350 kg0.350\text{ kg}0.350 kg of substance X at its boiling point.

The specific latent heat of vaporization of substance X is 225,000 J/kg225,000\text{ J/kg}225,000 J/kg.

Use the equation: thermal energy=mass×specific latent heat\text{thermal energy} = \text{mass} \times \text{specific latent heat}thermal energy=mass×specific latent heat

[2]

Internal energy and energy transfers Questions

  1. GCSE
  2. /Physics
  3. /Internal energy and energy transfers