Heat: Lesson 4 Heat vs. Temperature

What happens to the movement of molecules as they’re heated? /energy-forms-and-changeshttp://phet.colorado.edu/en/simulation /energy-forms-and-changes

What is temperature? Temperature is the average kinetic energy of matter. The more the molecules move the higher the temperature will be. =

Thermal Energy Thermal energy is the total amount of energy in a sample. It involves the temperature and amount of a substance. +

Which sample has more thermal energy? 50 mL at 100 °C 100 mL 100 °C Sample A Sample B =thermal energy

Which one has more thermal energy: A or B? 50 mL at 80 ° C10 mL at 100 ° C 100 mL temp increases from 22 °C to 38 ° C 100 mL temp increases from 22 °C to 29 ° C A B

Law of Conservation of Energy SystemSurroundings

The amount of energy released or absorbed by a process can be quantified by the following equation: q = m x x ΔT q = m = ΔT = 1 calorie is the amount of energy that it takes to raise 1 gram of water 1°C.

PRACTICE: A 100 gram sample of water is at 50°C. The water sample cools to 25°C. How many calories did the sample lose to the surroundings? q = m x x ΔT q = m = ΔT = (T final – T initial ) = (___ – ___) = ( _____ ) PLUG IN AND SOLVE:

PRACTICE: 200 mL of 50°C water is mixed with 75 mL of 90°C water. The final temperature of the water is 60.9°C. How much heat did the 50 °C water gain? q = ______ m = ______ ΔT = (T final – T initial ) = (___ – ___) = ( _____ ) q = m x x ΔT PLUG IN AND SOLVE:

PRACTICE: 200 mL of 50°C water is mixed with 75 mL of 90°C water. The final temperature of the water is 60.9°C. How much heat did the 90°C water lose? q = ______ m = ______ ΔT = (T final – T initial ) = (___ – ___) = ( _____ ) q = m x x ΔT PLUG IN AND SOLVE:

This example proves the _________________________because the energy ________ by the _______ water, 2180 calories, is equal to the energy _______ by the _______ water, 2180 calories. Hot WaterCold Water