calorimetry is the technological process of measuring energy changes of an isolated system called a...
TRANSCRIPT
![Page 1: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/1.jpg)
CALORIMETRY
![Page 2: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/2.jpg)
Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter
![Page 3: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/3.jpg)
Thermochemistry
The study of energy changes by a chemical system during a chemical reaction
![Page 4: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/4.jpg)
Isolated System
Calorimetry deals with an isolated system, where matter NOR energy can move in or out
![Page 5: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/5.jpg)
Laws of Thermodynamics
1st Law = energy cannot be created or destroyed but transferred
2nd Law = heat flows from hot to cold, and heat loss is equal to heat gained
![Page 6: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/6.jpg)
-mcΔt = nHm
Heat lost = heat gained
“system” “calorimeter”
nHm = -mcΔt
Ep = -Ek
![Page 7: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/7.jpg)
Within the calorimeter there is a known volume of liquid (usually water) in which the chemical reaction to be studied occurs
![Page 8: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/8.jpg)
Energy (as heat) is transferred between the chemical system and the water
![Page 9: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/9.jpg)
Calorimetry requires careful measurements of masses and temperature changes
the chemical energy lost by the chemical system is calculated by the thermal energy gained by the surroundings
![Page 10: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/10.jpg)
remember: thermal energy is the total kinetic energy
q = mcΔt
![Page 11: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/11.jpg)
remember potential energy of a reaction is the enthalpy
ΔH = nHm
![Page 12: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/12.jpg)
Assumptions in Calorimetry
![Page 13: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/13.jpg)
styrofoam is considered a perfect insulator…
energy lost to the calorimeter is ignored
![Page 14: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/14.jpg)
only the water releases or absorbs heat…
so we only need to use the specific heat capacity of water (4.19 kJ/kgC)
![Page 15: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/15.jpg)
volume of water is equal to (and interchangeable with) the mass of water…
mL = g
L = kg
![Page 16: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/16.jpg)
these assumptions allow the idea that energy gained by the calorimeter water equals the energy lost by the reaction and vice versa
![Page 17: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/17.jpg)
nHm = mcΔtcalorimeter
![Page 18: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/18.jpg)
Example 2
When excess zinc is added to 50.0mL of 0.25mol/L aqueous copper(II)sulfate, the calorimeter warms by 12.5°C. What is the molar enthalpy of reduction of aqueous copper(II) ions?
![Page 19: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/19.jpg)
Answer:
-209500J/mol
![Page 20: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/20.jpg)
Example 2
When 50.0mL of 1.0mol/L NaOH, initial temperature 17.4°C is mixed with 50.0mL of 1.0mol/L HCl, initial temperature 24.2°C. What is the molar enthalpy change for the neutralization of the base?
![Page 21: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/21.jpg)
Answer:
28492J/mol
![Page 22: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/22.jpg)
Bomb Calorimetry
Bomb Calorimetry
![Page 23: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/23.jpg)
professionals use a bomb calorimeter to measure the energies released and absorbed by reactions.
![Page 24: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/24.jpg)
bomb calorimetry minimizes heat loss with superior insulation and very exact temperature measurements giving more accurate enthalpies of reaction
![Page 25: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/25.jpg)
![Page 26: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/26.jpg)
Heat Change of the
Calorimeter Includes water, bomb, thermometer stirrir, container…
![Page 27: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/27.jpg)
the masses and heat capacities of all the components of the bomb calorimeter are constants…
![Page 28: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/28.jpg)
therefore we can use the formula
nHm = -CΔT
![Page 29: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/29.jpg)
Example 1
Consider a 1.00g sample of benzoic acid burning in a bomb calorimeter. The initial temperature is 25.00°C and the heat capacity of the calorimeter is 5.43kJ/°C. The combustion causes the temperature of the calorimeter to rise to 29.86°C. Using this data, what is the molar enthalpy of the combustion of benzoic acid?
![Page 30: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/30.jpg)
Answer:
-3223kJ/mol
![Page 31: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/31.jpg)
Example 2
A reaction in a bomb calorimeter absorbs 22.4kJ of heat energy. What is the initial temperature of the calorimeter if its final temperature was 24.22°C and its heat capacity is 28.7kJ/°C.
![Page 32: Calorimetry is the technological process of measuring energy changes of an isolated system called a calorimeter Calorimetry is the technological process](https://reader035.vdocuments.site/reader035/viewer/2022062520/5697bf8d1a28abf838c8c54c/html5/thumbnails/32.jpg)
Answer:
+25C