1. Chemistry: data analysis volume, density, temperature, scientific notation
8/27/15

2. Music to remember https://www.youtube.com/watch?v=IhtgKHYZti0

3. volume Is the space occupied by an object. Derived Unit: m3
Most useful is cm3
Works well for solid objects w/ regular dimensions
But not so well for liquids or solids w/ irregular shapes
1 cm3 = 1 mL
volume

5. Density Is a ratio that compares the mass of an object to its volume.
Density (ρ) = mass (m)/volume (v)
Units: g/cm3=mass (g)/volume (cm3)
1 cm3 = 1 mL
It’s easier to lift a grocery bag full of paper goods than it is to lift a grocery bag full of soup cans.
Volume of the bags are identical…so it must have something to do with the amount of mass packed into the same volume!

6. The quarter and the foam weigh the same…but the density of the quarter is much greater than the density of the foam because the quarter occupies a much smaller space.

7. I calculate Density (ρ) = mass (m)/volume (v)
Units: g/cm3=mass (g)/volume (cm3)
Mass = 13.5 g
Volume = 5.0 cm3
What is the density of the aluminum?
13.5g/5.0 cm3 =
2.7 g/cm3
Every sample of pure aluminum has the same density (that goes for any pure sample of anything).

8. densities

9. I calculate
Suppose a sample of aluminum is placed in a 25 mL graduated cylinder containing 10.5 mL of water. The level of water rises to 13.5 mL. What is the mass of the aluminum, if its density is 2.7 cm3 ?

10. We calculate
What is the volume of a sample that has a mass of 20 g and a density of 4 g/mL?

11. We calculate
A metal cube has a mass of 20 g and a volume of 5g/cm3. Is the cube made of pure aluminum? Explain your answer.

12. You Calculate
What is the density of a piece of wood that has a mass of 25.0 grams and a volume of 29.4 cm3 ?

13. You Calculate
A piece of wood that measures 3.0 cm by 6.0 cm by 4.0 cm has a mass of 80.0 grams. What is the density of the wood? Would the piece of wood float in water? (HINT: volume=LxWxH)

14. Practice
I threw a plastic ball in the pool for my dog to fetch. The mass of the ball was 125 grams. What must the volume be to have a density of g/mL? (I want it to float of course!)

15. Temperature conversions
The temperature of an object is a measure of how hot or cold the object is relative to other objects.
Hot and cold are qualitative descriptions.
To get quantitative data, you need tools to measure with.
In a thermometer, liquid expands when it’s heated and contracts when cooled.
The tube contains liquid in a narrow enough area that small changes in temperature can be detected.

16. Celsius Devised by Anders Celsius, a Swedish astronomer.
He used temps where water freezes and boils for his scale b/c they were easy to reproduce.
Freezing pt = 0
Boiling pt = 100
Divided distance between these pts into 100 equal units, or degrees Celsius
Celsius

17. Kelvin (K)
Scottish physicist and mathematician, William Thomson (Lord Kelvin)
SI base unit for temperature
Water freezes at 273 K and boils at 373 K

18. Converting between the two scales
To convert temperature reported in Celsius to Kelvins, just add 273.
-39 °C = 234 K
357 ° C = 630 K
To convert from the Kelvin scale to Celsius, just subtract 273.
266 K – 273 = -7 °C
332 K – 273 = 59 °C

19. I calculate
Convert 26 °C into Kelvins
Convert 650 K into °C

20. We calculate
Convert 15 °C into Kelvins
Convert 150 K into °C

21. You Calculate
Convert 5 °C into Kelvins
Convert 245 K into °C