Energy Potential energy- energy of position or composition. Potential energy- energy of position or composition. Kinetic energy- energy of motion Kinetic energy- energy of motion KE= ½ m·v 2 KE= ½ m·v 2 As temperature increases, so does the velocity of particles. As temperature increases, so does the velocity of particles.

The temperature of a substance is a measure of the average kinetic energy of its particles.

Heat Energy Energy transferred due to a temperature difference. Measured in Joules or calories

Specific Heat Capacity (c) The heat needed to raise the temperature of 1g of a substance 1˚C. The heat needed to raise the temperature of 1g of a substance 1˚C. Water’s heat capacity is high: Joule Water’s heat capacity is high: Joule or 1 calorie or 1 calorie so c w = J/g∙˚C so c w = J/g∙˚C

Q = m∙c∙∆T Heat = mass ∙ specific heat∙ change gained or lost in temp Ex: How much heat is lost when a solid aluminum ingot with a mass of 4110g cools from 660.0˚C to 25˚C? c Al = 0.903J/g˚C ∆T = – 25 = 635˚C ∆T = – 25 = 635˚C Q = (4110g)(0.903J/g˚C)(635˚C)=2,360,000 J

Specific Heat Capacities (J/g·°C) copper0.387 air1.00 ethyl alcohol2.45 water4.18 What happens to the change in temperature of equal masses of copper and water when equal amounts of heat energy are given? m = 1.0gQ = 10.0J Copper: 10.0J = 1.0g (0.387 J/g·°C)ΔT Water: 10.0J = 1.0g (4.18 J/g·°C) ΔT ΔT = 25.8 °C ΔT =°C ΔT = 2.4°C

Calorimeter A device used to measure the energy given off or absorbed during a chemical or physical change. A device used to measure the energy given off or absorbed during a chemical or physical change.

A piece of an unknown metal with mass 23.8g is heated to 100.0˚C and dropped into 50.0 ml of water at 24.0˚C. The final temperature of the system is 32.5˚C. What is the specific heat of the metal? Metal m=23.8 g ∆T= =67.5˚CWaterm=50.0g∆T= =8.5˚CC=4.184J/g˚C

Heat gained by the water: Q=(50.0g)(4.184J/g˚C) (8.5˚C) = Joules = Joules Heat gained by water = heat lost by metal J = (23.8 g) (c) (67.5˚C) J = (c) C=1.1J/g˚C