# Changes

```Changes
 Exothermic
vs
 Endothermic
Changes
 Exothermic
 Reaction that releases
heat
vs
 Endothermic-Absorbs
heat
Exothermic
Endothermic
making ice cubes
melting ice cubes
formation of snow in clouds
conversion of frost to water vapor
condensation of rain from water
vapor
evaporation of water
a candle flame
forming a cation from an atom in the
gas phase
mixing sodium sulfite and bleach
rusting iron
cooking an egg
burning sugar
producing sugar by photosynthesis
Heat versus temperature
HEAT (q)
 Measure of the total
energy in a substance
 Sum of energy of all
particles(kinetic energy
and potential energy)
 Units: Joule (kgxm2/s2)
kJ
TEMPERATURE
 Related to the Average KE
of particles in a sample
 Units:
K or C
3 things that the quantity of heat
transferred are dependent on:
 Nature of the material changing
temperature
 Mass of the material changing temperature
 Size of temperature change
Specific heat
 Amount of energy needed to raise the temp of 1 g of a




substance 1 C (a calorie is the amount of heat required
to raise the temperature of 1 g of H2 O 1 C) 1 cal=4.184 J
Helps you to determine how many joules or calories it
takes a known mass of something to change from one
temperature to another
Symbol: cp
Unit: J/(g.K)
Formula: cp= q/mT
 q-amt of energy lost or gained
 m-mass
 T= temperature change
```