Drill
• How should we set up a lab notebook? What
should we include, etc?
General Tips for Lab Notebook
• Leave a blank page or two at the beginning of your
notebook so you can create a Table of Contents
• Number pages
• Use permanent ink
• Draw only a single line through all errors written, so
they still can be seen
• Record all observations and explanations of why
they happened
• Be as descriptive as possible with titles and headings
for your experiments; for example do not write
"Chemical Synthesis," instead write "Preparation of
Alum"
Agenda
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Notebook Set up
Calorimetry Problems
Lab – Proc B
Lab Table
Calorimetry Notes
Calorimetry
• Calorimetry is the study
of the heat released or
absorbed during
physical and chemical
reactions
• For a certain object, the
amount of heat energy
lost or gained is
proportional to the
temperature change
Calorimetry
A calorimeter can be a thermos, Styrofoam
cup, or any container that minimizes heat loss
The size of the temperature change depends
on:
How much heat is released or absorbed
The heat capacity of the surroundings
Specific Heat Review
• Specific Heat – energy needed to raise 1
gram of a substance by 1˚C
• Specific heat is a physical property
• Liquid water’s specific heat is 4.184 J/gºC
• q = (m) x (c) x (Δ T)
• If a hot object is put in water in a
calorimeter, then the heat absorbed by the
water is equal to the heat given off by the
substance.
ΔH of water = - ΔH of substance
Because of the law of
conservation of matter …
qmetal= -qaq
qmetal = -qaq
mmcmDTm = -mwcwDTw
cm =
-mwcwDTw
mmDTm
Practice Problem 1
• Example:
• You put 103.0 g of aluminum in 100.0 grams
of boiling water. The water temperature
changes from 100.0ºC to 90.0ºC, while the
aluminum temperature goes from 25.0ºC to
70.0ºC. What is the specific heat of
aluminum?
Practice Problem 1
qmetal = -qaq
H2O
Al
-(103.0g)(c)(70.0-25.0C) = (100.0g)(4.184J/g°C)(90.0-100.0 C)
-4635 g°C(c) = -4180 J
c = 0.902 J/g°C
Practice Problem 2
• A 46.2 g sample of copper is heated to 95.4ºC
and then placed in a calorimeter containing
75.0 g of water at 19.6ºC. The final
temperature of both the water and the copper
is 21.8ºC.
• What is the specific heat of copper?
Practice problem 2
qcu = mcΔT
qh2o = mcΔT
mcΔT = qcu = qh2o = mcΔT
(46.2 g) ccu (73.6 C) = (75 g) (4.184 J/gC) (2.2C)
ccu = 0.20 J/g°C
Another type…
• What if something dissolves in the water?
What happens to the total mass???
• You add them up! The whole solution
increases (or decreases) in heat.
Drill
• A chemistry student dissolves 4.51 grams of
room temperature sodium hydroxide in
100.00 g of water at room temperature,
19.5°C. As the sodium hydroxide dissolves,
the temperature of the solution increases to
31.7°C. Determine the heat of solution of
the sodium hydroxide in J/mol.
Answer
• 47.3 kJ/mol
Calorimetry Lab