Question 1
Question detail
A 0.8 kg sample of water is heated from 25 °C to 75 °C. What is the change in thermal energy of the water in joules?
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
Question
Type
exam_style
Style
Topic
Energy changes in a system, and the ways energy is stored before and after such changes
Question
A 0.8 kg sample of water is heated from 25 °C to 75 °C. What is the change in thermal energy of the water in joules?
Answer
The change in thermal energy is 32 000 J. This answer is strong because it uses the correct mass (0.8 kg), specific heat capacity of water (4200 J kg⁻¹ °C⁻¹), temperature change (50 °C) and applies the formula ΔQ = m c ΔT correctly.
Explanation
The question checks that the student can identify the specific heat capacity of water, set up the calculation with the correct units, and compute the thermal energy change.
Common mistake
Confusing Units of Measurement
Students often confuse joules with kilograms when identifying thermal energy changes.
Always remember that thermal energy is measured in joules, while mass is measured in kilograms. Keep the units distinct when performing calculations.
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