P3 - Specific Heat Capacity

What is specific heat capacity?

The amount of energy required to raise the temperature of 1 kg of a substance by 1°C

What is the equation for change in thermal energy?

Change in thermal energy = mass × specific heat capacity × temperature change

What is the symbol equation for specific heat capacity?

ΔE = m × c × Δθ

What is ΔE in the specific heat capacity equation?

Change in thermal energy (in joules, J)

What is m in the specific heat capacity equation?

Mass of the substance (in kilograms, kg)

What is c in the specific heat capacity equation?

Specific heat capacity (in J/kg°C)

What is Δθ (delta theta) in the equation?

Change in temperature (in °C)

What are the units of specific heat capacity?

Joules per kilogram per degree Celsius (J/kg°C)

If a question asks for thermal energy and gives mass, SHC, and temperature change, what should you do?

Multiply them: ΔE = m × c × Δθ

How do you convert joules to kilojoules?

Divide by 1000

What is the specific heat capacity of water?

4,200 J/kg°C

Does water have a high or low specific heat capacity?

High

Why does water take a long time to heat up or cool down?

Because it has a high specific heat capacity

A 2 kg sample of water is heated from 20°C to 100°C. How much thermal energy is transferred?

ΔE = 2 × 4200 × 80 = 672,000 J or 672 kJ

What is the temperature change if an object goes from 30°C to 75°C?

45°C

What is the temperature change if an object cools from 90°C to 20°C?

70°C

An aluminium plate (1.5 kg) is heated from 20°C to 200°C. SHC of aluminium is 913 J/kg°C. What energy is stored?

ΔE = 1.5 × 913 × 180 = 246,510 J or 246.51 kJ

A hot water bottle cools from 80°C to 20°C, releasing 756,000 J. SHC of water = 4200 J/kg°C. What is the mass?

m = ΔE ÷ (c × Δθ) = 756000 ÷ (4200 × 60) = 3 kg

What does a high specific heat capacity mean?

The substance requires more energy to change its temperature

What does a low specific heat capacity mean?

The substance heats up or cools down quickly with little energy

What is the energy transferred when a 4 kg block with SHC of 500 J/kg°C is heated by 10°C?

ΔE = 4 × 500 × 10 = 20,000 J

How can you increase the thermal energy change?

Increase the mass, SHC, or temperature change

Why is it important to know SHC in real-life applications?

To design systems like radiators, heaters, or cooking equipment efficiently

In what units should mass be in SHC calculations?

Kilograms (kg)

In what units should temperature change be in SHC calculations?

Degrees Celsius (°C)

What is meant by a 'system' in specific heat capacity questions?

The substance or object whose thermal energy is being considered

What causes the thermal energy of a system to change?

A change in temperature due to heating or cooling

What is the difference between heat and temperature?

Heat is energy (in joules), temperature is a measure of how hot something is (in °C)