Lecture 16- Thermodynamics 2 Flashcards
1
Q
Calorimetry
A
the measurement of heat transfer using a calorimeter (a device used to determine the amount of heat transferred)
2
Q
specific heat capacity of water
A
4.184J/gC
3
Q
^q
A
^q=mc^T
- q=heat lost or gained by a substance
- m=mass of that substance
- c=specific heat capacity of that substance
- ^T=temp change of that substance
4
Q
^q vs. ^H
A
- ^qrxn= the heat lost or gained in the experiment that took place in the calorimeter
- ^Hrxn= the heat lost or gained in the balanced chemical equation
5
Q
Hess’s Law
A
- The overall enthalpy change will be the same if a reaction is carried out in one step or in several steps
- manipulate equations
6
Q
Standard enthalpy of formation
A
- a hypothetical value that indicates how much heat would be lost or gained during the formation of one mole of a compound from the most common form of its elements in their standard states
- under standard conditions
- most stable form of any element in its standard state is zero
^Hrxn=sumn^H(products) - sumn^H(reactants)
7
Q
relating to calorimetry
A
^q=mc^T
8
Q
How much was gained/lost?
A
opposite signs, same number
9
Q
what is the specific heat?
A
- manipulate to solve for c
10
Q
what is the enthalpy change for the formation of 1 mol of
A
^Hrxn=^q/m and M=m/L
- Use q=mc^T to find q
- Use M=m/L to find m
- and plug into ^Hrxn=^q/m
11
Q
Write the chemical equation
A
- write and cross out dissolving
12
Q
find the heat of reaction ^Hrnx
A
^Hrxn=^q/m and M=m/L
- Use q=mc^T to find q
- Use M=m/L to find m
- and plug into ^Hrxn=^q/m
13
Q
Hf equals
A
Hrxn
14
Q
Hrxn label
A
Kj/mol
15
Q
determine the enthalpy change given multiple equations
A
Hess’s law
- flip then switch sign
- multiply then multiply
- add values
