**THERMAL ENERGY**

Thermal energy is heat energy. In equation form, heat energy is represented as [tex]Q[/tex]. The unit for thermal energy is Joules (J). You can determine how much heat energy is lost or gained when the temperature of a substance changes.

The equation to solve for change in thermal energy is [tex]\Delta Q = Cm\Delta T[/tex].

- [tex]Q[/tex] = Thermal energy (J)
- [tex]C[/tex] = Specific heat of the object ([tex]J/(g \cdot °C)[/tex])
- [tex]m[/tex] = Mass (g)
- [tex]\Delta T[/tex] = Change in temperature (°C)

**Solve for change in thermal energy ([tex]Q[/tex]):**

1. A 10.0 g piece of copper wire, sitting in the sun, reaches a temperature of 80.0ºC. How many Joules are released when the copper cools to 40.0ºC? The specific heat capacity of copper is 0.377 [tex]J/(g \cdot °C)[/tex].

- [tex]Q = ?[/tex]
- [tex]C = 0.377 \, J/(g \cdot °C)[/tex]
- [tex]m = 10.0 \, g[/tex]
- [tex]\Delta T = 80.0ºC - 40.0ºC[/tex]

2. The specific heat capacity of water is 4.184 [tex]J/(g \cdot °C)[/tex]. How much thermal energy is required to change the temperature of 700.0 g of water from 25.6ºC to 75.4ºC?

3. How much thermal energy is released when a 201 g piece of blown glass at an initial temperature of 150ºC is cooled to 25ºC? The specific heat capacity of glass is 0.837 [tex]J/(g \cdot °C)[/tex].

4. How much heat must be absorbed by a 500 g pot of water in order to raise the temperature of the water from 20°C to 30°C? (Specific heat capacity of water is 4.184 [tex]J/(g \cdot °C)[/tex]).

5. An element has a specific heat of 0.18 [tex]J/(g \cdot °C)[/tex]. If 10 g of this element are heated and release 345 J of energy, what would be the resulting change in temperature?