1. Intro to Thermochemistry

2. Objectives:
Today I will be able to:
Differentiate between temperature and heat
Explain the process of heat transfer
Calculate the enthalpy of a system
Informal assessment – monitoring student questions and interactions as they complete the heat calculations
Formal assessment – analyzing student responses to the calculations and exit ticket

3. Lesson Sequence Evaluate: Warm Up
Explain: Intro to Thermochemistry Notes
Elaborate: Heat Calculations Practice
Evaluate: Exit Ticket

4. Warm Up What is temperature?
Is there a difference between heat and temperature?
If there is a difference, explain what the difference is.

5. Objectives Today I will be able to:
Differentiate between temperature and heat
Explain the process of heat transfer
Calculate the enthalpy of a system

6. Homework
Specific heat calculations

7. Agenda Warm Up Intro to Thermochemistry Notes
Specific Heat Practice Problems
Exit Ticket

8. Intro to Thermochemistry
The study of heat
Intro to Thermochemistry

9. Temperature vs. Heat Temperature Heat
Average kinetic energy of molecules in a sample
Energy is transferred between to objects due to temperature difference
Heat transfer is always high to low

10. Direction of heat transfer

11. Enthalpy (ΔH)
Measure of the heat content in a system
As temperature increases, the enthalpy of the system increases
Positive Δ H indicates an endothermic reaction
Negative Δ H indicates an exothermic reaction

12. Endothermic Reaction Reaction that absorbs heat
C + H2O kJ  CO + H2

13. Exothermic Reaction Reaction that releases heat
C3H8 + 5 O2  3 CO2 + 4 H2O kJ

14. Measuring enthalpy Enthalpy (ΔH) is measured in Joules (J) Equation:
ΔH = mcΔT
Mass
Temperature change
Specific Heat

15. Specific heat
the amount of heat required to raise the temperature of 1 gram of a substance 1 o C.
Different for every substance
Look up in a table of values

16. Example of Specific Heat Values

17. Sample Calculation
How many joules of heat are needed to raise the temperature of 10.0 g of aluminum from 22°C to 55°C, if the specific heat of aluminum is 0.90 J/g°C?
Answer: 297 J

18. Complete the practice calculations at your desk
Complete the practice calculations at your desk. We will finish the calculations in class tomorrow
Heat Calculations

19. Exit Ticket
A glass of ice water is set on the counter. Describe the direction of heat transfer and why it occurs.