A 2 kg object is heated from 20°C to 80°C. If the specific heat capacity is 0.5

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Question: A 2 kg object is heated from 20°C to 80°C. If the specific heat capacity is 0.5 J/g°C, how much heat is absorbed? (2019)

Options:

Correct Answer: 80 kJ

Exam Year: 2019

Solution:

Heat absorbed (Q) = mcΔT = (2000 g)(0.5 J/g°C)(60°C) = 60,000 J = 60 kJ.

A 2 kg object is heated from 20°C to 80°C. If the specific heat capacity is 0.5 J/g°C, how much heat is absorbed? (2019)

A 2 kg object is heated from 20°C to 80°C. If the specific heat capacity is 0.5 J/g°C, how much heat is absorbed? (2019)

Step 1: Identify the mass of the object. The mass is given as 2 kg. Convert this to grams because the specific heat capacity is in J/g°C. 2 kg = 2000 g.
Step 2: Identify the specific heat capacity. It is given as 0.5 J/g°C.
Step 3: Determine the change in temperature (ΔT). The object is heated from 20°C to 80°C. Calculate ΔT: 80°C - 20°C = 60°C.
Step 4: Use the formula for heat absorbed (Q): Q = mcΔT, where m is mass, c is specific heat capacity, and ΔT is the change in temperature.
Step 5: Substitute the values into the formula: Q = (2000 g)(0.5 J/g°C)(60°C).
Step 6: Calculate the heat absorbed: Q = 2000 * 0.5 * 60 = 60,000 J.
Step 7: Convert the heat absorbed from joules to kilojoules: 60,000 J = 60 kJ.

Specific Heat Capacity – The amount of heat required to raise the temperature of a unit mass of a substance by one degree Celsius.
Heat Transfer Calculation – Using the formula Q = mcΔT to calculate the heat absorbed or released during a temperature change.
Unit Conversion – Understanding the need to convert mass from kilograms to grams when using specific heat capacity in J/g°C.