Chapter 11 T.9? are we gonna pull through on this one....

Thermochemistry

heat changed that occur during chemical or physical reactions

Define energy

• the capacity for doing work of supplying heat

chemical potential energy

• energy stored within bonds (structural units)

How/why does heat energy transfer from one object to another

• because of temperature difference

• always goes from hot → cold

• aka more energy → less energy

What is the the difference between heat and temperature

• temp is the average of kinetic energy

• heat is energy

Describe Exothermic and its signs, draw the diagram

• heat is lost to the surroundings

• container feels hot

• the change in heat is negative

• energy is lost

• Diagram goes straight, peak, downward

Describe Endothermic and its signs, draw the diagram

• heat is absorbed from the surroundings

• container is cold

• the change in heat is positive

• energy is gained

• diagram starts down, peaks, then goes to the middle

What is a Calorie

the amount of heat required to raise 1 g of water 1 degree Celsius

1 kcal=

1 food calorie

4.18 Joule=

I cal

Is Joule or Calorie bigger

Calorie, like a quater to a dollar

why does water moderate temperature

has a high specific heat

Heat capacity-

amount of heat needed to increase temperature of an object 1 degree celsius

Specific heat-

energy required to change the temp of 1 gram of a substance 1 degree celsius

What is the Energy Equation (labeled)

q= CxMx▵T

q- heat energy gained or lost

c- specific heat (j/g degrees C) or (cal/ g degrees C)

m- mass

▵t- change in temp

NEXT IS ON WARMING COOLING CURVE FOR WATER!!

draw as you go

negative- 0 degrees

A-B:

• Solid

• The C in q= CxMx▵T for solid is 0.5/g degrees C

2. 0-0 degreese

B-C

• heat of fusion

• uses H_f x M where H_f=80 cal/g

3. 0-100 degrees

C-D

• liquid

• The C in q= CxMx▵T for liquid is 1 cal/ g degrees C

4. 100- 100

D-E

• heat of vaporization

• uses H_v x M where H_v= 540 cal/g

5. 100- 100+

E- F

• gas

• The C in q= CxMx▵T for gas is 0.4 cal/ g degrees c

What is Hess’s Law

if you add two+ reactions together to get an overall reaction, then you can add the heats of the reactions together to get the heat for the overall reactions:

• keep it

• flip it

• multiply it