1. Thermochemistry
Chapter 17

2. TWO Trends in Nature Order  Disorder (Entropy)
  
High energy  Low energy (Enthalpy)
 > 

3. Energy & Chemistry ENERGY is the capacity to do work or transfer heat.
HEAT is the form of energy that flows between 2 objects because of their difference in temperature.
Other forms of energy —
light
electrical
kinetic and potential

4. Potential & Kinetic Energy
Potential energy — energy a motionless body has by virtue of its position.

5. Potential & Kinetic Energy
Kinetic energy — energy of motion

6. Heat transfers until thermal equilibrium is established.
Thermodynamics
Thermodynamics is the science of heat (energy) transfer.
Heat energy is associated with molecular motions.
Heat transfers until thermal equilibrium is established.

7. Directionality of Heat Transfer
Heat always transfer from hotter object to cooler one.
EXOthermic: heat transfers from SYSTEM to SURROUNDINGS.
Heat(system) goes down
Heat(surr) goes up

8. Directionality of Heat Transfer
Heat always transfer from hotter object to cooler one.
ENDOthermic: heat transfers from SURROUNDINGS to the SYSTEM.
Heat(system) goes up
Heat (surr) goes down

9. Energy & Chemistry All of thermodynamics depends on the law of
CONSERVATION OF ENERGY.
The total energy is unchanged in a chemical reaction.
If PE of products is less than reactants, the difference must be released as KE.

10. Energy Change in Chemical Processes
PE of system dropped. KE increased. Therefore, you often feel a temperature increase.

11. UNITS OF ENERGY
1 calorie = heat required to raise temp. of 1.00 g of H2O by 1.0 oC.
1000 cal = 1 kilocalorie = 1 kcal
1 kcal = 1 Calorie (a food “calorie”)
But we use the unit called the JOULE
1 cal = joules
James Joule

12. HEAT CAPACITY
The heat required to raise an object’s temperature by 1 ˚C.
Which has the larger heat capacity?

13. Specific Heat Capacity
Specific Heat Capacity (or specific heat ) is the amount of heat it takes to raise the temperature of 1g of the substance 10C

14. Calculating Specific Heat
Specific heat= heat (J or cal)
mass (g) x change in temperature
Add : Q 3-4 on page 510

15. Assignment: Read pages 505-509
Copy the vocabulary terms on page 505 onto a flippy page foldable
Answer the four key concept questions on page 505 and Q 1-2 on page 507
Calculating specific heat
Q 3-4 on page 510