Transcript Temperature vs Heat - Red Hook Central Schools

Energy
Kinetic energy = energy of motion
Energy
Potential energy = stored energy
1. energy of position due to gravity
Energy
Potential energy = stored energy
2. energy stored in
chemical bonds
Law of Conservation of Energy
Energy can not be
created or destroyed,
only converted from
one form to another.
When energy is RELEASED in a
chemical reaction, it is called….
EXOTHERMIC
When energy is ABSORBED in a
chemical reaction, it is called….
ENDOTHERMIC
Units of Energy
Energy is measured in JOULES
Also in calories or kilocalories (food)
How many calories are in a kilocalorie?
Units of Energy
How many calories in the hamburger?
420 kilocalories
What is temperature?
A measure of the average kinetic energy of
the particles in a sample of matter.
All atoms are moving!
High temperature = moving faster
Once again……
TEMPERATURE
=
AVERAGE KINETIC
ENERGY
Temperature Scales
Celcius:
water freezes
Zero degrees
water boils
100 degrees
Temperature Scales
Kelvin: 0 K = absolute zero (-460 oF)
all motion of particles stops!
Water freezes @ 273 K
Water boils @ 373 K
Kelvin never goes below zero (no negative
numbers!)
Temperature Scales
Kelvin = Celsius + 273
Celsius = Kelvin – 273
If it is 32O Celsius, what temperature is it in
Kelvin?
If it is 100 Kelvin, what temperature is it in
Celsius?
Temperature Scales
Standard Temperature
0 degrees Celsius
273 Kelvin
(in Table A)
At what temperature does liquid
nitrogen boil?
• 77 Kelvin
• -195 Celsius
• -320 Farenheit
What is Heat?
Heat is the sum total of all the kinetic
energy in a sample of matter.
How is heat different from temperature???
Heat ≠ Temperature
Both the water in the bath tub and in the cup
are at 25 oC
Which contains more HEAT?
Heat Capacity
The amount of energy (in JOULES) needed to
raise the temperature of the sample by 1 oC
Which water sample has a higher heat capacity?
Specific Heat Capacity
The amount of energy (in JOULES) needed to
raise the temperature of 1 gram of the sample by
1 oC
Which water sample has a higher specific heat ?
Specific Heat
Specific heat measures how easily something can
absorb (or then lose) heat.
LOW specific heat = little energy for something to
heat up.
HIGH specific heat = lots of energy to heat
something up
Every substance has its own unique specific heat
value.
Specific Heat Capacity
In your experience, which substance below
has a higher specific heat capacity (takes
more energy to heat it up?)