Presentation is loading. Please wait.

Presentation is loading. Please wait.

Slide 1 of 33 Chemistry 17.2. © Copyright Pearson Prentice Hall Slide 2 of 33 Measuring and Expressing Enthalpy Changes A burning match releases heat.

Similar presentations


Presentation on theme: "Slide 1 of 33 Chemistry 17.2. © Copyright Pearson Prentice Hall Slide 2 of 33 Measuring and Expressing Enthalpy Changes A burning match releases heat."— Presentation transcript:

1 Slide 1 of 33 Chemistry 17.2

2 © Copyright Pearson Prentice Hall Slide 2 of 33 Measuring and Expressing Enthalpy Changes A burning match releases heat to its surroundings in all directions. How much heat does this exothermic reaction release? You will learn to measure heat flow in chemical and physical processes by applying the concept of specific heat. 17.2

3 © Copyright Pearson Prentice Hall Measuring and Expressing Enthalpy Changes > Slide 3 of 33 Calorimetry What basic concepts apply to calorimetry? 17.2

4 Slide 4 of 33 © Copyright Pearson Prentice Hall > Measuring and Expressing Enthalpy Changes Calorimetry Calorimetry is the precise measurement of the heat flow into or out of a system for chemical and physical processes. 17.2

5 Slide 5 of 33 © Copyright Pearson Prentice Hall > Measuring and Expressing Enthalpy Changes Calorimetry In calorimetry, the heat released by the system is equal to the heat absorbed by its surroundings. Conversely, the heat absorbed by a system is equal to the heat released by its surroundings. 17.2

6 Slide 6 of 33 © Copyright Pearson Prentice Hall > Measuring and Expressing Enthalpy Changes Calorimetry The insulated device used to measure the absorption or release of heat in chemical or physical processes is called a calorimeter. 17.2

7 Slide 7 of 33 © Copyright Pearson Prentice Hall > Measuring and Expressing Enthalpy Changes Calorimetry Constant-Pressure Calorimeters The heat content of a system at constant pressure is the same as a property called the enthalpy (H) of the system. 17.2

8 Slide 8 of 33 © Copyright Pearson Prentice Hall > Measuring and Expressing Enthalpy Changes Calorimetry Constant-Volume Calorimeters Calorimetry experiments can be performed at a constant volume using a bomb calorimeter. 17.2

9 © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide 9 of

10 © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide 10 of

11 © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide 11 of

12 © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide 12 of

13 © Copyright Pearson Prentice Hall Slide 13 of 33 Practice Problems for Sample Problem 17.2 Problem Solving Solve Problem 13 with the help of an interactive guided tutorial.

14 © Copyright Pearson Prentice Hall Measuring and Expressing Enthalpy Changes > Slide 14 of 33 Thermochemical Equations How can you express the enthalpy change for a reaction in a chemical equation? 17.2

15 © Copyright Pearson Prentice Hall Measuring and Expressing Enthalpy Changes > Slide 15 of 33 Thermochemical Equations In a chemical equation, the enthalpy change for the reaction can be written as either a reactant or a product. 17.2

16 Slide 16 of 33 © Copyright Pearson Prentice Hall > Measuring and Expressing Enthalpy Changes Thermochemical Equations A chemical equation that includes the enthalpy change is called a thermochemical equation. 17.2

17 Slide 17 of 33 © Copyright Pearson Prentice Hall > Measuring and Expressing Enthalpy Changes Thermochemical Equations The heat of reaction is the enthalpy change for the chemical equation exactly as it is written. 17.2

18 © Copyright Pearson Prentice Hall > Measuring and Expressing Enthalpy Changes Slide 18 of 33 Thermochemical Equations 17.2 Exothermic Reaction

19 © Copyright Pearson Prentice Hall > Measuring and Expressing Enthalpy Changes Slide 19 of 33 Thermochemical Equations 17.2 Endothermic Reaction

20 © Copyright Pearson Prentice Hall Measuring and Expressing Enthalpy Changes > Slide 20 of 33 Thermochemical Equations Simulation 22 Simulate a combustion reaction and compare the ∆H results for several compounds.

21 © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide 21 of

22 © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide 22 of

23 © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide 23 of

24 © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide 24 of

25 © Copyright Pearson Prentice Hall Slide 25 of 33 Practice Problems for Sample Problem 17.3 Problem Solving Solve Problem 15 with the help of an interactive guided tutorial.

26 Slide 26 of 33 © Copyright Pearson Prentice Hall > Measuring and Expressing Enthalpy Changes Thermochemical Equations 17.2

27 Slide 27 of 33 © Copyright Pearson Prentice Hall > Measuring and Expressing Enthalpy Changes Thermochemical Equations The heat of combustion is the heat of reaction for the complete burning of one mole of a substance. 17.2

28 © Copyright Pearson Prentice Hall Slide 28 of 33 Section Quiz -or- Continue to: Launch: Assess students’ understanding of the concepts in Section 17.2 Section Quiz

29 © Copyright Pearson Prentice Hall Slide 29 of The change in temperature recorded by the thermometer in a calorimeter is a measurement of a.the enthalpy change of the reaction in the calorimeter. b.the specific heat of each compound in a calorimeter. c.the physical states of the reactants in a colorimeter. d.the heat of combustion for one substance in a calorimeter Section Quiz.

30 © Copyright Pearson Prentice Hall Slide 30 of Section Quiz. 2. For the reaction CaO(s) + H 2 O(l)  Ca(OH) 2 (s),  H =  65.2 kJ. This means that 62.5 kJ of heat is __________ during the process. a.absorbed b.destroyed c.changed to mass d.released

31 © Copyright Pearson Prentice Hall Slide 31 of Section Quiz. 3.How much heat is absorbed by 325 g of water if its temperature changes from 17.0°C to 43.5°C? The specific heat of water is 4.18 J/g°C. a.2.00 kJ b.3.60 kJ c.36.0 kJ d.360 kJ

32 © Copyright Pearson Prentice Hall Slide 32 of Which of the following is a thermochemical equation for an endothermic reaction? a.CH 4 (g) + 2O 2 (g)  CO 2 (g) + 2H 2 O(g) kJ b kJ + 2H 2 O(l)  2H 2 (g) + O 2 (g) c.CaO(s) + H 2 O(l)  Ca(OH) 2 (s) 65.2 kJ d.2NaHCO 3 (s) 129 kJ  Na 2 CO 3 (s) + H 2 O(g) + CO 2 (g) 17.2 Section Quiz.

33 © Copyright Pearson Prentice Hall Slide 33 of Oxygen is necessary for releasing energy from glucose in organisms. How many kJ of heat are produced when 2.24 mol glucose reacts with an excess of oxygen? C 6 H 12 O 6 (s) + 6O 2 (g)  6CO 2 (g) + 6H 2 O(g) kJ/mol a.4.66 kJ b.9.31 kJ c.1048 kJ d.6290 kJ 17.2 Section Quiz.

34 END OF SHOW


Download ppt "Slide 1 of 33 Chemistry 17.2. © Copyright Pearson Prentice Hall Slide 2 of 33 Measuring and Expressing Enthalpy Changes A burning match releases heat."

Similar presentations


Ads by Google