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45 Cards in this Set
- Front
- Back
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Energy |
Capacity to do work |
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Kinetic energy |
Energy due to motion |
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Potential Energy |
Energy due to position or composition |
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System (chemistry) |
Usually a closed container of a substance or a chemical reaction |
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Surroundings |
Everything else that is part of the system |
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Heat |
AKA thermal energy • Energy transferred as a result of a temperature difference between system and surroundings |
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Work |
All other forms of energy transfer when an object is being moved by a force |
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q |
Heat |
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w |
Work |
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∆E |
Change in energy |
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q + w = |
∆E |
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(+) heat |
Heat absorbed |
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(-) heat |
Heat released |
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(+) work |
Work done on |
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(-) work |
Work done by |
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(+) ∆E |
Internal energy increases |
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(-) ∆E |
Internal energy decreases |
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State functions |
Anything with ∆ in front of it |
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∆E |
Only depends on final and initial state ∆E= E(final) - E(initial) |
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P |
Pressure |
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P = |
Force/Area |
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Units: atm |
Atmospheres |
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P(ext) |
(constant) external pressure |
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∆V |
Change in volume |
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1 atm • 1L = |
101.3 J
101.3 J ----------- 1L•1atm |
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w = |
-P(ext)•∆V |
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V final > V initial |
Gas expands
∆V is (+) W is (-) work done BY system |
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V final < V initial |
Gas compressed ∆V is (-)W is (+) work done ON system |
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H |
Enthalpy |
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∆H |
Change in enthalpy Heat measured at constant P |
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∆H = |
qp = ∆E + P•∆V |
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1) Reactions NOT involving gases |
Very small volume changes P∆V ~ 0 ∆H~∆E |
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2) Reactions where moles of gas DOES NOT change |
Ex: H2 (g) + Cl2 (g) = 2HCl (g) P∆V = 0 P∆V = 0∆H = ∆E ∆H = ∆E |
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3) Reactions where mole of gas DOES change |
2CO (g) + O2 (g) = 2CO2 (g)
P∆V not equal 0 P∆V <<< q•p ∆E not equal to ∆H ∆H~∆E
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Exothermic |
qp = ∆H < 0 Heat is released as a "product" Temperature of surroundings increases |
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Exothermic |
qp = ∆H < 0 Heat is released as a "product" Temperature of surroundings increases |
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Endothermic |
qp = ∆H < 0 Heat is absorbed, can be shown as "reactant" Temperature of surroundings decreases |
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q α [heat is proportional to] |
m [mass] ∆T [change in temperature] C [constant]
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Specific heat capacity |
C: amount of heat needed to raise the temp. of 1g of substance by 1°(1k) |
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Molar Heat capacity (C) |
The amount of heat needed to raise temp. Of 1 mole of substance by 1K (°C)
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Specific Heat capacity of water 💧 |
C= 4.184 J/gK |
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Molar heat capacity of water 💧 |
C |
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Mass of H2O with 50 mL |
50 mL • 1 g H2O ------------- 1mL H2O |
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Oz. to g |
M= 1.00 oz • 28.35 g ----------. = 28.35 g 1 oz |
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Celsius to Kelvin |
+ 273.15 |
