chapter 16 energy and chemical change
DESCRIPTION
Chapter 16 Energy and Chemical Change. Nature of energy. Energy – the ability to do work or produce heat Kinetic energy – energy of motion Potential energy – stored energy Chemical potential energy – stored energy because of composition. Measuring heat. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Chapter 16 Energy and Chemical Change](https://reader035.vdocuments.net/reader035/viewer/2022062422/56813663550346895d9df137/html5/thumbnails/1.jpg)
![Page 2: Chapter 16 Energy and Chemical Change](https://reader035.vdocuments.net/reader035/viewer/2022062422/56813663550346895d9df137/html5/thumbnails/2.jpg)
Energy – the ability to do work or produce heat◦ Kinetic energy – energy of motion◦ Potential energy – stored energy
Chemical potential energy – stored energy because of composition
![Page 3: Chapter 16 Energy and Chemical Change](https://reader035.vdocuments.net/reader035/viewer/2022062422/56813663550346895d9df137/html5/thumbnails/3.jpg)
Heat – energy process of flowing from a warmer object to a cooler object◦ Calorie – the amount of heat required to raise the
temperature one degree Celsius◦ Joule – SI unit of heat and energy
![Page 4: Chapter 16 Energy and Chemical Change](https://reader035.vdocuments.net/reader035/viewer/2022062422/56813663550346895d9df137/html5/thumbnails/4.jpg)
When your body breaks down sugars and fats to form carbon dioxide and water, these exothermic reactions generate heat that can be measured in Calories
![Page 5: Chapter 16 Energy and Chemical Change](https://reader035.vdocuments.net/reader035/viewer/2022062422/56813663550346895d9df137/html5/thumbnails/5.jpg)
Specific heat – amount of heat required to raise the temperature of one gram of that substance by one degree Celsius
Units - J/g ⁰ C Large specific heats = Large amount of
energy to change temperature (water) Small specific heats = Small amounts of
energy to change temperature (gold)
![Page 6: Chapter 16 Energy and Chemical Change](https://reader035.vdocuments.net/reader035/viewer/2022062422/56813663550346895d9df137/html5/thumbnails/6.jpg)
q = m x c x ∆Tq = mc∆Tq (heat)c (specific heat)m (mass of sample) ∆T (change in temperature)
![Page 7: Chapter 16 Energy and Chemical Change](https://reader035.vdocuments.net/reader035/viewer/2022062422/56813663550346895d9df137/html5/thumbnails/7.jpg)
The temperature of a sample of iron with a mass of 10.0g changed from 50.4⁰C to 25.0 ⁰ C with the release of 114J heat. What is the specific heat of iron?
q = mc∆T Heat (q)
◦ 114J Mass (m)
◦ 10.0g Specific Heat (c)
◦ X Change in temperature (∆T)
◦ 50.4⁰C - 25.0 ⁰ C = 25.4 ⁰ C 114 = 10.0(x)25.4 114 = 254(x) X=.44881 Final answer 0.449J/g ⁰ C (3 significant figures and units)
![Page 8: Chapter 16 Energy and Chemical Change](https://reader035.vdocuments.net/reader035/viewer/2022062422/56813663550346895d9df137/html5/thumbnails/8.jpg)
Calorimeter – insulated device used for measuring the amount of heat absorbed or released during a chemical or physical process
![Page 9: Chapter 16 Energy and Chemical Change](https://reader035.vdocuments.net/reader035/viewer/2022062422/56813663550346895d9df137/html5/thumbnails/9.jpg)
Thermochemistry is the study of heat changes that accompany chemical reactions and phase changes
![Page 10: Chapter 16 Energy and Chemical Change](https://reader035.vdocuments.net/reader035/viewer/2022062422/56813663550346895d9df137/html5/thumbnails/10.jpg)
Enthalpy (H) is the heat content of a system at constant pressure
Enthalpy of reaction◦ ∆Hrxn=Hproducts – Hreactants
![Page 11: Chapter 16 Energy and Chemical Change](https://reader035.vdocuments.net/reader035/viewer/2022062422/56813663550346895d9df137/html5/thumbnails/11.jpg)
Endothermic = absorbs heat giving the ∆Hrxn a positive number
Exothermic = releases heat giving the ∆Hrxn a negative number