1. Warm-up
What is the final temperature of a g piece of metal if it absorbs joules of heat and its specific heat capacity is J/g°C? The initial temperature of the glass is 22.0°C.

2. Warm Up
Rank liquids, solids, and gasses in order of increasing kinetic energy.
What state(s) of mater have a definite volume?
What state(s) of matter have a definite shape?
What is one property that both solids and liquids share?

3. Energy of Phase Changes
Heat, Day 2
Whitaker
21 November 2013

4. q=mcΔT q = heat absorbed or released (most often in Joules)
m = mass of the sample in grams
c = the specific heat of the substance (J/g°C)
ΔT = the change in temperature in degrees Celsius
When solving a word problem, start by writing down your givens and figuring out what you are looking for. Then solve for the variable.

5. When a substance changes temperature.
Specific Heat = The amount of energy required to raise the temperature of 1 gram of a substance by 1°C.
Note! Every substance has a unique specific heat.
q=mcΔT

6. Example
How many joules of heat are needed to raise the temperature of 10.0 g of aluminum from 22°C to 55°C, if the specific heat of aluminum is J/g°C?

7. Example
Calculate the heat capacity of a piece of wood if g of the wood absorbs 6.75×104 joules of heat, and its temperature changes from 32°C to 57°C

8. Example
To what temperature will a 50.0 g piece of glass raise if it absorbs joules of heat and its specific heat capacity is 0.50 J/g°C? The initial temperature of the glass is 20.0°C.

9. What happens when a substance changes phases.
Heat of fusion- energy required to melt a substance. 334 J/g for water
q= m Hf
Heat of vaporization- energy required to vaporize a substance J/g for water
q= m Hv

10. Example
How much energy is required to melt grams of water?

11. Example
How much energy is required to vaporize grams of water?

12. Example
How much energy is required to melt grams of water?

13. What happens when you heat an ice cube until it all vaporizes?
Remember when you heat a substance one of two things happens:
The substance changes temperature
The substance changes state of matter
This means we need to calculate the energy involved in each step then add it all up.

14. Example
Calculate the energy needed to turn 50 grams of liquid water with a temperature of 56°C to water vapor with a temperature of 150°C.

15. Example
An ice cube with a mass of 15 grams and an initial temperature of -10°C is heated until all 15 grams of water is a vapor with a temperature of 105°C. Calculate the energy needed to do this.