1. Heat flow lab-ette: record before/during/after obsercations in lab book
You and your partner:
Get 1 baggie with a scoop of LiCl
Get 1 baggie with a scoop of NH4NO3
Get 1 large pipette or a small beaker full of water and go to your lab area.
Name each of the compounds. Determine if the compound is ionic or covalent. Mix in enough water to dissolve the salt. Record 2 observations for each bag.

2. Vocbulary follow up: read Pages 338-340 in your text.
define the following terms in your lab book:
heat
temperature
intensive property

3. Enthalpy “H”
The total energy content in a sample.

4. Heat Capacities
Heat is calculated by its effect on the temperature of a given quantity of substance.
Ex. If 200g of water are increased by 10 degrees, the total amount of heat can be calculated.

5. 10- Thermochemistry (Causes of Change)
The study of heat changes that occur during a chemical reaction
10- Thermochemistry (Causes of Change)

6. Exothermic---Endothermic
Thermochemistry is concerned with the flow of heat.
System= what you are focusing upon
Surroundings= everything else.
If heat flows out of the system it is EXOTHERMIC
If heat enters the system  it is ENDOTHERMIC

7. What is heat? Heat is a form of energy.
(energy is either heat or a capacity to do work)
When low and high temperature objects come into contact…the energy transfer is heat.
The Heat flow is high to low.
From higher energy objects to lower energy objects.

8. Kinetic energy and temperature
Measure of the average kinetic energy of the particles in an object.
Atoms and molecules can move in 3 ways
Translation  
Rotation
Vibration
The total of this movement energy is
KINETIC ENERGY

9. Units of heat calorie small ‘c’ SI UNIT= Joule (J)
Amount of heat energy needed to raise 1g of water 1 degree Celsius.
Food calories are 1000 regular calories.
SI UNIT= Joule (J)
1 calorie = Joules
1000 calories = = 1 Food Calorie
1 KJ=1000 Joules

10. Heat Capacity
Amount of heat needed to raise an objects temperature exactly 1C
With a more massive object, heating up will take more heat.

11. Specific Heat “C”
Amount of heat it takes to raise 1 g of a substance, 1 degree celcius
Water is J/g°C
Plastic = 1.2 J/g°C
Metals have lower specific heats
Aluminum = .90 J/g°C

12. Calculating heat q= m C Δ T
q=heat
m=mass
C=specific heat, material dependent constant
Δ T= Change in temperature
HEAT = Mass x specific heat x change in temp
How much heat does it take to raise 1kg of water 30 degrees Celsius?
How much heat for the same amount of aluminum to increase 30 degrees Celsius?
PROBLEMS

13. Molar Heat Capacity The same thing with a little twist.
q= n C Δ T
This equation solves the heat required in a certain number of moles.
The book gives “C” in units of J/n K
Uses Kelvin rather than Celsius
The problem solving is the same.
Determine the heat energy needed to raise 10.0 mol of Mercury 7.5 K. C for mercury is 27.8 J/n K.

14. ΔH = q = m C ΔT Change in Enthalpy = heat flow= mass x specific heat x change in temp
H = enthalpy You may run across the term “enthalpy” in a lab or the text. Enthalpy is the total amount of heat a substance has. When a reaction occurs energy (heat) flows into or out of the substances. The change in enthalpy is ΔH. We will not use enthalpy in this course.

15. Warm up
When a 0.20g filament of Tungsten undergoes an increase in temperature of 125°C when 3.35 J of energy are applied. What is the Specific Heat of Tungsten?
q= m C Δ T q= m= C=
Δ T=
Tungsten filament

16. Warm Up
A Coke in Mexico has 0.7 KJ of energy per serving. How many calories is that?
Steps: Convert KJ to Joules 1KJ = 1000 J Convert Joules to calories 4.184J = 1 calorie

17. Calorimetry
The accurate and precise measurement of heat change for chemical and physical processes.
Calorimetry uses a calorimeter.
insulating cup
thermometer
calorimeter
Relate to lab 15 specific heat of metals.

18. Heat lost = Heat gained What loses heat? What gains heat?
40g of Aluminum at 80C is added to 60g of water at 20C
What loses heat? What gains heat?
After a few moments, the equilibrium temp is 28C
Calculate the specific heat of aluminum? (CAl)
qlost by Al =qgained by H2O
mAlCAlΔTAl=mH2OCH2OΔTH2O
Solve for CAl
Get responses for the questions.
Aluminum loses heat
Water gains heat

19. Convert 17. 4 calories to Joules. Convert 3420 joules to kilojoules

20. Lab 15 Specific Heat of Metal
Test specific heat of lead. (Begin w/hot water in the beaker)
Set up for the 2nd metal (not 2nd trial) while waiting for equilibrium.
After 1st test, complete data analysis # 1-3 using the data analysis help sheet. [Each person in the group completes this)