Heat: Calculating Calories, Conservation of Matter and Equilibrium Investigation 5 “Energy Transfer” Chemical Interactions Grade 8

Calorie Temperature is measured in degrees Celsius (*C). Heat is not measured in degrees Celsius. Heat is measured in calories (cal). The calorie is the unit of heat in the metric system.

Calculating Heat The amount of heat needed to change the temperature if a mass of water is measured in calories.

cal = m x T Calorie Equation The equation for calculating the amount of heat needed to heat up or cool down a mass of water is… cal = m x T Need to know calorie equation for test

Calorie Equation Continued The number of calories needed to change the temperature of a mass of water is equal to the mass of water (in grams) times the temperature change (in degrees Celsius). Water: 1mL = 1 g = 1*Celsius Must know that 1 ml=1g this is only true with water

Conservation of Energy The amount of energy in a system is always the same - no energy is ever created, and no energy is destroyed. Review don’t need to add

Energy Transfer Energy can transfer from one place to another. Energy can be transformed from one kind of energy into another kind of energy. i.e. Mixing hot and cold water = warm water Review don’t need to add

Equilibrium Every time a particle with high kinetic energy from the hot water hit a particle with low kinetic energy from the cold water, the kinetic energy of both particles changed: The hot water particle slowed down and the cold water particle sped up. Add this to notes

Final average speed The final average speed of the particles was faster than the particles in the the original cold water, and slower than the original hot water. Add to notes

Equilibrium Energy transfer continues as particles continue to bang into one another. But the number of particles gaining energy will be the same as the number of particles loosing energy. The temperature will hold steady. Don’t’ need to add to notes, next slide will give def.

Equilibrium When a system is in balance, and there is no net energy transfer going on, the system is in equilibrium. When mixing hot and cold water, the final temperature was its equilibrium temperature. Equilibrium: The condition of a system when no observable change is taking place. Add to notes

Energy Transfer Vocabulary Calorie (cal): A unit of heat; the amount of heat needed to raise the temperature of 1 g (gram) of water to 1*(*degree)C. Conduction: The transfer of energy as a result of contact between particles. Add all vocab to notes

Energy Transfer Vocabulary Energy Transfer: The movement of energy from a location with more energy to a location with less energy.

Energy Transfer Vocabulary Heat: A form of energy related to the kinetic energy of particles. Kinetic Energy: The energy due to motion. The kinetic energy of particles is heat. Don’t need to add to notes

Energy Transfer Vocabulary Temperature: A measure of the average kinetic energy of the particles of a substance. Conservation of Energy: Energy is never created or destroyed during energy transfers.

FOSS Web FOSS Web Multimedia: Mixing Hot and Cold Water Energy Flow http://www.fossweb.com/