1. Topic 4 Transformations and Conservation of Energy

2. Energy - The ability to do work. Different forms include chemical, electrical, thermal, potential, and kinetic. Potential- stored energy available to do work. Kinetic- energy in motion.

3. Conservation of Energy The law of conservation of energy states that energy cannot be created or destroyed, but can change forms. These are transformations.

4. Energy Transformations Energy can be transformed into other forms. Example: In a solar panel the Sun (electromagnetic) is converted into into electrical energy.

5. Transformations generator  (electrical) Battery  (chemical) defroster (thermal) ignition (electrical)

6. Open and Closed Systems A closed system would not permit loss of matter outside the system. Energy is conserved. Example: insulation In an open system, energy is lost. Energy is not conserved.

7. Phase Changes In a phase change energy is absorbed into a system. For example, ice absorbs energy, increasing the motion of the molecules. Ice becomes a liquid. The energy required is called heat of fusion.

8. Phase Changes When liquid water absorbs energy, the molecules move faster, and the temperature of the water increases. The energy needed to raise 1 g 1°C is called the specific heat.

9. Phase Changes When the energy of the molecules becomes high enough the vapor pressure exceeds the atmospheric pressure, and the liquid boils. This energy is called heat of vaporization.

10. Energy Units calorie- the amount of energy it takes to raise 1 gram of water 1 degree Celsius. 1,000 calories = 1 Calorie 1 calorie = 4.2 Joules 1 kilojoule = 1,000 Joules

11. Heat of Fusion It takes 334 Joules to change one gram of ice to one gram of water. How many joules does it take to change 10 grams of ice to 10 grams of water?

12. Specific Heat It takes 4.2 joules to raise one gram of water 1 degree celsius. How many joules does it take to raise 10 grams of water 20 degrees celsius?

13. Heat of Vaporization It takes 2,260 joules of energy to change 1 gram of water from a liquid to a gas. How many joules would it take to change 30 grams of liquid water to a gas?

14. Total Energy You can add the heat of fusion, specific heat and heat of vaporization to get the total energy required to change a solid to a gas. You will find the heat required to change water from a solid to a gas in class.

15. The End