1. Chapter 14: Expansion and TemperaturePg

2. Linear Thermal Expansion of Solids
Most solids get bigger when heated and smaller when cooled.
Water is the exception, getting largest when at 4 degrees Celsius.
That’s why fish don’t freeze.

3. Cont
We can measure the expansion (growing) of solids by using a length-temperature graph.
We can also measure mathematically, using an equation similar to y = mx +b

4. Cont
The change of the length of the wire is equal to the constant times the original length of the wire times the temperature.
Constant will be different for each solid and is determined by a chart.
Coefficient of linear expansion is fish

5. Linear expansion
Useful in thermostats – the bimetallic strip of copper and iron expands at different rates in different temperatures, causing the curling of the metal in specific ways, controlling what you read as the temperature (see video)

6. Thermal Volume Expansion of Solids
Volume of a solid after it is heated. Used for solids with shape that do not expand in a linear fashion

7. Thermal expansion of liquids and gasses
Liquids are more sensitive to temperature than solids
Use the same formula as solids for liquids
Gases tend to expand as far as their containers will allow, so the temperature must be raised substantially before any change will be noticed

8. Conversion of Temperatures

9. Charles’s Law
Use to show the relationship between volume and temperature (use Kelvin temperature)

10. Boyle’s Law
Use to show the relationship between volume and pressure (can use atm or torr or mm Hg for pressure)

11. Gay-Lussac’s Law
Used to show relationship between pressure and temperature

12. Combined Gas Law
Used to show the relationship between volume, temperature, and pressure.
Can be used as long quantity of gas is known

13. Ideal Gas Law
Ideal gas law used when nothing is known or constant – used for real-world situations
R is universal gas constant (8.315 J/(K times mol)

14. STP Standard Temperature and Pressure (STP) Temperature: 273.15 K
Pressure: kPa or 1 atm

15. Van der Waals gases
Van der Waals made an equation that can be used when volume and pressure do not interact as they should according to the ideal gas laws
Laws that follow van der Waal’s law are called van der Waals gases
See next slide

16. Van der Waals formula

17. Homework
Page 323 Q1,2,5,12-16, 26-33