1. Calorimetry Practice Problems

2. Common Core Connection
Objectives
Today I will be able to:
Calculate the heat absorbed and released in a chemical reaction
Informal assessment – monitoring student interactions and questions as they complete the practice problems
Formal assessment – analyzing student work from the practice problems and exit ticket
Common Core Connection
Make sense of problems and persevere in solving them
Reason abstractly and quantitatively

3. Lesson sequence Evaluate: Warm Up Directed Practice Problems
Formal assessment
Directed Practice Problems
Informal assessment
Individual Practice Problems
Informal/formal assessment
Evaluate: Exit Ticket

4. Warm Up
Carbon exists in two natural forms: graphite and diamond. Each form can be combusted:
C(graphite) + O2(g)  CO2(g) ∆H = kJ
C(diamond) + O2(g)  CO2(g) ∆H = kJ
Calculate ∆H of the conversion of graphite to diamond: C(graphite)  C(diamond)
HW: Finish Calorimetry Problems

5. Objectives Today I will be able to:
Calculate the heat absorbed and released in a chemical reaction

6. Homework
Study for Thermochemistry Quiz on Wednesday, April 15

7. Agenda Warm Up Directed Practice Problems Individual Practice Problems
Exit Ticket

8. Directed Practice Problems

9. Hess’s Law
Calculate ∆H for the reaction 4 NH3 (g) + 5 O2 (g)  4 NO (g) + 6 H2O (g), from the following data.
N2 (g) + O2 (g)  2 NO (g) ∆H = kJ
N2 (g) + 3 H2 (g)  2 NH3 (g)∆H = kJ
2 H2 (g) + O2 (g)  2 H2O (g) ∆H = kJ

10. Calorimetry
Example 1:
You put g of aluminum in grams of boiling water. The water temperature changes from 100.0ºC to 90.0ºC, while the aluminum temperature goes from 25.0ºC to 70.0ºC. What is the specific heat of aluminum?

11. Calorimetry H2O Al -(103.0g)(c)(70.0-25.0°C)
(100.0g)(4.184J/g°C)( °C) =
-4640 g°C(c) =
-4180 J
c = J/g°C

12. Another type…
What if something dissolves in the water? What happens to the total mass???
You add them up! The whole solution increases (or decreases) in heat.

13. Example
A chemistry student dissolves 4.51 grams of room temperature sodium hydroxide in g of water at room temperature, 19.5°C. As the sodium hydroxide dissolves, the temperature of the solution increases to 31.7°C. Determine the heat of solution of the sodium hydroxide in J/mol.

14. Answer
47.3 kJ/mol

15. Let’s Practice Calorimetry Problems
You may check Ms. Ose’s answer key as you work

16. Exit Ticket
Based on the calorimetry data presented below, is the reaction endothermic or exothermic? Explain.