Today is Thursday,
December 17th, 2015
Pre-Class:
We’re spending a large portion of today
reviewing for the test tomorrow. Ask questions
now or forever hold them or something...
THINGS TO DO:
-Have the Specific Heat and Thermochemistry
Round Robin Review worksheets out.
Today’s Agenda
• Review.
• Review?
• Review!
Before we do class questions…
• Do you have any questions?
Worksheet Practice
• Specific Heat Worksheet
– 7, 9 (only if you haven’t already)
• Thermochemistry Round Robin Review
– 14, 16
• Thermochemistry Problems Worksheet One
– 21-23, 1-7
Review Question 1
• When do you use the equation ΔH =
m*Cp*ΔT?
– When temperature is changing but not phase.
Review Question 2
• When do you use ΔH = mol*ΔHfus/vap?
– When phase is changing but not temperature.
Review Question 3
• Convert 458 calories to Joules.
– 1916.272 Joules
• 1 calorie = 4.184 Joules
4.184 Joules
• 458 calories *
1 calorie
Review Question 4
• If you are heating water from -15⁰C to 79⁰C,
how many “steps” would the problem require
to solve?
–3
• Warming the solid
• Melting the solid
• Warming the liquid
Review Question 5
• How much heat energy is required to raise the
temperature of 74.7g of pyrex glass by 43⁰C?
The specific heat capacity of pyrex is 0.837 J/g
⁰C.
– 2688.53 J
• ΔH = m*Cp*ΔT
• ΔH = 74.7*0.837*(43)
• ΔH = 2688.53 J
Review Question 6
• How many torr are in 533 mm Hg?
– 533 torr
Review Question 7
• How many kPa are in 3.200 atm?
– 324.2 kPa
Review Question 8
• How many kPa are in 52.1 torr?
– 6.94 kPa
Review Question 9
• BONUS NON-CHEMISTRY QUESTION
• You may wager any/all of your points.
• Category: Geography
• Montevideo is the capital of which country?
– Uruguay.
Review Question 10
• Given the following reaction:
• 2CO2 + 2H2O  C2H4 + 3O2
• ΔH = 1410.7 kJ
• How much energy is needed to produce 36g of
oxygen gas?
– 529.01 kJ
• 36 g O2 = 1.125 mol O2
• 1.125 mol * 1410.7 kJ
3 mol O2
Review Question 11
• Would it be good for a student to not study
Hess’s Law for the coming test?
– No. It wouldn’t.
– It would also be impossible for a teacher to put a
lengthy-type question as that into a review like
this.
– So instead, here’s a reminder to study it.
Review Question 12
• What is the ΔHf0 of O2?
– 0 kJ/mol.
– Remember that free/diatomic (basically anything
in its natural state) elements have no heat of
formation.
Review Question 13
• How do you calculate ΔHf0 for a reaction?
– Add up the ΔHf0 values for the products and then
subtract the ΔHf0 values for the reactants, making
sure to adjust for mol totals.