Chemistry Unit 9 Thermochemistry and Equilibrium

Conduction

heat transfer by COLLIDING of particles

Convection

heat transfer by CIRCULATION of a fluid (or gas)

Radiation

heat transfer by FLOW OF ELECTROMAGNETIC radiation

energy

CAPACITY for doing work/supplying heat

All chemical reactions and changes in physical state involve either

1. release of heat

2. absorption of heat

system

specific part of the universe that contains the reaction

surroundings

everything else

ENDOTHERMIC process

SYSTEM GAINS HEAT and SURROUNDINGS COOL DOWN

EXOTHERMIC process

SYSTEM LOSES HEAT and SURROUNDINGS GAIN HEAT

endothermic is defined as

positive (q has a positive value)

exothermic is defined as

negative (q has a negative value)

endothermic

ABSORBS energy (Endo=IN)

exothermic

RELEASES energy (Exo=OUT)

Average Kinetic Energy

Temperature

Heat of Fusion

energy required to change from SOLID to LIQUID

Heat of Vaporization

energy required to change from LIQUID to GAS

Calorie

quantitiy of heat needed to raise the temp of 1g of pure water by 1⁰C

1 calorie is how many Joules?

4.184 J

Heat Capacity

increase the temperature of an object exactly 1⁰C

Specific Heat Capacity

the amount of heat is takes to raise the temperature of 1 gram of a substance by 1 degree Celsius

exothermic is faster with more collisions

Calorimetry

the measurement of the heat into or out of a system

heat released EQUALS

heat absorbed

the change in enthalpy

delta H of the reaction

if heat is a PRODUCT

it is EXOTHERMIC

if heat is a REACTANT

it is ENDOTHERMIC