# CH0002 - Lecture 1

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1. Energy is...
...the capacity to do work
2. First Law of Thermodynamics states...
• Energy can be neither created nor destroyed, merely transferred into a different form:
• Conservation of Energy
3. Universe =
System + Surroundings
4. System =
• Part of the universe we are interested in...
• Solutions in a beaker
• Chemical reactor
• Electrochemical cell
5. Surroundings =
Everything else in contact with the system, which can influence its state
6. Open system...
Exchange of BOTH energy and matter with the surroundings
7. Closed system...
Exchange of energy BUT NOT matter with the surroundings
8. Isolated...
No exchange of energy and matter with the surroundings
9. Work is...
...the transfer of energy causing motion against a force
10. Work =
Pressure =
• Work = Force X displacement
• Work = Pressure X change in volume
• Pressure = Force / Area
11. Heat is...
...the transfer of energy as a result of a temperature difference between the systems and surroundings
12. Q + means...
Q - means...
• Q + means heat IN (absorbed by system)
• Q - means head OUT (absorbed by surroundings)
13. W + means...
W - means...
• W + means work DONE ON (a system)
• W - means work DONE BY (a system)
14. We use a calorimeter...
• To measure heat changes
• It is a reaction vessel surrounded by a water bath containing a thermometer
15. Heat supplied Q =
• Q = mwater X Cwater X ΔT
• Where C=heat capacity
• Where m=mass
16. At constant pressure Q =...
• Q=ΔH
• Where H=Enthalpy
17. At constant volume Q=...
• Q=ΔU
• Where U = Internal energy
18. ΔH =...
• ΔH = ΔU + PΔV
• Remember W=P X ΔV
19. The reaction enthalpy is...
The measured heat change for a reaction at atmospheric pressure
20. Enthalpy is a state function, which means that...
A change in enthalpy depends only on the difference between the starting state and the final state, not on the route taken
21. Hess' Law definition 1
The standard enthalpy (ΔHo) of a reaction is the sum of the standard enthalpies of the reactions into whcih the overall reaction may be divided, even if this division is artificial.
22. Hess' law definition 2
The enthalpy change accompanying a chemical change is independent of the route by which the chemical change occurs.
 Author: james14hunter ID: 259011 Card Set: CH0002 - Lecture 1 Updated: 2014-01-29 11:51:33 Tags: CH0002 Lecture Folders: CH0002 - Lecture 1 Description: CH0002 - Lecture 1 Show Answers: