What is energy?








Energy is the ability to do work or produce heat.

The law of conservation of energy states that energy can be created and destroyed.

Heat is the flow of energy from a warmer object to a cooler object.

Chemical potential energy is energy stored in a substance because of its composition.

A calorie is the SI unit of heat and energy.

Cooks the food we eat

Propels vehicles that transport us

Allows photosynthesis to occur to start the food chain

Energy from burning fuels heats or cools the classroom

Allows you to think and write

Cells are factories that run on energy derived from the food we eat

The ability to do work or produce heat

Potential energy vs. kinetic energy – 2 basic forms

Potential energy – energy of position

Kinetic energy – energy of motion

Ex. Roller coaster

Contain both kinetic and potential energy

Kinetic energy – directly related to constant random motion of particles – prop. To temp.

Potential energy depends on composition – chemical bonds, arrangement of atoms, etc.

Energy can be neither created nor destroyed, it can only be converted from one form to another.

1 st Law of thermo.

 q

Energy flowing from a warmer object to a

cooler object.

As energy flows, change in temperature

Calorie – energy needed to raise one gram of water one º C.

When your body breaks down sugars and fats to form carbon dioxide and water, these reactions generate heat energy that can be measured in calories.

SI unit is the joule which equals 0.2390 calories.

1J= 0.2390 calories

1cal=4.184 Joules.

kcal=Calories (bigC)= 1 nutritional calorie

Pg. 492 practice problems

The specific heat of any substance is the amount of heat required to raise the temperature of one gram of that substance by one degree Celsius.

So, for water, that’s 4.184J/g


º C

Cp = q .

m x ∆T

Cp = specific heat q = heat absorbed or released by substance m= mass

∆T = change in temperature

Pg. 495 #’s 4-6

The relationship between heat and specific heat… q=c ·m·ΔT q total

=q water

+ q material or c water

·m water

·ΔT water

Table pg. 492

= c material

·m material

·ΔT material

(Sounds like…?)

Is an insulated device to measure the change in heat during a chemical reaction.