Chapter 5, Section 3B, C

1
Density and Temperature Conversion

• Chapter 5, Section 3B, C

2
Temperature Conversions

• Outside the US, most countries used degrees
  Celsius to measure temperature
• Water freezes at 0C and boils at 100 C
• As things cool down, particles slow down
• Scientists use the Kelvin temperature scale
  because it is based on absolute zero
• A theoretical temperature at which electrons
  stops moving
• There is no such things as negative Kelvin
• Kelvin is not stated as degrees Kelvin, but
  simply as Kelvin and is abbreviated K

3
Conversions Celsius to Kelvin

• Each Kelvin unit is exactly equal to one Celsius
  degree
• O K -273 C
• Therefore, 0 C 273 K
• Add 273 degrees to Celsius to get Kelvin
• Subtract 273 to get Kelvin to Celsius
• Try these
• 244 K __________C
• -29
• Water boils at ____________ K
• 373

4
Density

• Density is how heavy something is for its size
• Density is mass divided by volume or
• D m/v
• Where D equals density, m equal mass, and v equal
  volume
• You can change the formula to solve for other
  parts
• m vD
• v m/D

5
Density

• You will often hear density referred to as mass
  per unit volume
• Lets think about that
• Mass is how much matter the object has
• Per simply means divided by
• Unit volume is a measure of how much space it
  takes up

6
What are the Units of Density?

• Mass units would include
• Grams for very small objects
• Kilograms for larger objects
• Volume units would include
• Cubic centimeters for small objects
• Cubic meters for large objects
• Milliliters for small amounts of liquid
• Liters for larger amounts of liquid
• Most commonly you will see g/cm3 or g/mL

7
Density Practice

• Lets practice some density problems
• What is the density of a liquid that has a volume
  of 23.5 mL and a mass of 35.062 g?
• D m/v
• 35.062 g/23.5ml D 1.492 g/mL
• What is the mass of medallion that has a density
  of 21 g/cm3 and a volume of 2.6 mL?
• m vD
• 2.6 mL x 21 g/cm3 m 55.64 g