1. Heat Transfer and Endothermic/Exothermic Reactions

2. Methods of Heat Transfer
Heat is the transfer of energy that may results in a change of temperature.
When two substances exchange heat, the amount they exchange will be equal to each other.
qgain = -qlost
This maintains the Law of Heat Exchange.
Heat is transferred by conduction, convection, or radiation.

3. Conduction
Conduction occurs when two objects transfer heat by direct contact. They must be touching.
Heat will travel from the warmer object to the colder object.
The heat is transferred through the collisions that occur between the substances.

4. Convection
Heat is transfer by currents created from fluid particles (liquids or gases).
The wind and ocean currents are created through convection.
The hotter matter will heat the cooler matter.

5. Radiation
Heat is transferred through electromegnetic radiation and does not require matter.
The sun heats the Earth and fires can warm the air and objects around it.

6. Insulators are materials that prevent the transfer of heat.
Coolers, Styrofoam, ceramics, rubber are all good insulators.
Conductors are materials that allow the transfer of heat between two objects.
Cooking pots, metals, electrical wires are all great conductors.

7. Endothermic Reactions
Reactions that absorb energy from their surroundings are endothermic.
Since the surrounding loses energy, it will feel colder.
Phase changes in which the temperature is increasing are endothermic.

8. Exothermic Reactions
Reactions that donate energy to their surroundings are exothermic.
When the surrounding gains the energy, it will feel warmer.
Phase changes in which the temperature is decreasing and burning matter are exothermic.

9. Conservation of Energy with Thermochemistry
The energy in a closed system should stay constant and just change forms.
Most systems are not closed like a vehicle engine.
We say they lose energy, but it is simply transferred to thermal energy.