Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Specific heat capacity () is defined as the amount of energy required to raise the temperature of of a substance by (or ).
The internal energy of a substance increases when it is heated, causing an increase in the average kinetic energy of its particles, which is observed as a temperature rise.
The SI unit for specific heat capacity is \text{J kg}^{-1} ^\circ\text{C}^{-1} or .
Substances with a high specific heat capacity, such as water (c \approx 4200 \text{ J kg}^{-1} ^\circ\text{C}^{-1}), require more energy to change their temperature compared to substances with low specific heat capacity like lead (c \approx 130 \text{ J kg}^{-1} ^\circ\text{C}^{-1}).
Thermal capacity (or heat capacity) is the energy required to raise the temperature of an entire object by , calculated as .
In experimental setups, lagging (insulation) is used to minimize thermal energy loss to the surroundings to ensure accurate measurements of .
📐Formulae
💡Examples
Problem 1:
A block of copper is heated from to . Given that the specific heat capacity of copper is 390 \text{ J kg}^{-1} ^\circ\text{C}^{-1}, calculate the thermal energy supplied.
Solution:
Explanation:
To find the energy, we multiply the mass (), the specific heat capacity (c = 390 \text{ J kg}^{-1} ^\circ\text{C}^{-1}), and the change in temperature ().
Problem 2:
An electric immersion heater rated at is used to heat of a liquid for . The temperature of the liquid rises from to . Calculate the specific heat capacity of the liquid.
Solution:
Energy supplied . Using c = \frac{Q}{m\Delta\theta} = \frac{12,000}{0.5 \times (32 - 20)} = \frac{12,000}{0.5 \times 12} = \frac{12,000}{6} = 2,000 \text{ J kg}^{-1} ^\circ\text{C}^{-1}
Explanation:
First, calculate the total energy supplied by the heater (). Then, rearrange the specific heat capacity formula to solve for using the mass and the observed temperature change.