1. Density
Think back to our definition of matter (anything that has mass and takes up space).
What is another word for how much space something takes up? (volume)
How can we relate mass and volume (density)

2. What is Density? Can be used to identify a substance
Ratio of mass to volume for a specific substance

3. Density Formula Mass Volume Density = Units 1 cm3 = 1mL Liquid: g/mL
Solid: g/cm3
Gas: g/L D M V
1 cm3 = 1mL
1 cm3 = 1mL

4. Arrangement of atoms in different metals is similar.
Individual atoms are packed very close together.
Therefore, differences in density between metals are usually based on the size and mass of the atoms
Copper atoms are smaller than aluminum atoms.
More copper atoms can fit in the cube.
Copper atoms are also heavier than aluminum atoms.
The combination of more and heavier atoms makes copper more dense than aluminum.
Wood is made from a long molecule called cellulose.
Cellulose is made from glucose molecules connected together in long chains.
Glucose is made from carbon, hydrogen, and oxygen atoms.
The structure of wood is made of many cellulose molecules stacked together. Plastic and wood can have similar densities because they are made from similar atoms and are both composed of long chains. The main difference is how closely packed the chains are to one another.
Most plastics are made from chains of carbon and hydrogen atoms connected together.
Molecules in plastics can have: different length chains, twisted, tangled, or layered chains, different atoms or molecules connected to the C–H chain.
If the different atoms are heavy atoms, the plastic tends to be more dense, if they are light atoms, the plastic tends to be less dense.
Polyethylene is made up only of carbon and hydrogen atoms. The mass of carbon is pretty low. The mass of hydrogen is the lowest of all the atoms.
These low masses help explain why polyethylene has a low density.
Another reason is that these long skinny molecules are loosely packed together.
Polyvinyl chloride is made up of carbon, hydrogen and chlorine atoms.
If you compare polyvinyl chloride to polyethylene, you will notice that there are chlorine atoms in some places where there are hydrogen atoms in the polyethylene.
Looking at the chart, chlorine has a large mass for its size.
Therefore polyvinyl chloride is more dense than polyethylene.

5. Density of Water
Why is water most dense at 4°C, a temp lower than freezing?

6. Properties Of Density Varies with temperature
Inversely proportional to temperature
Draw D T and D T

9. Examples
What is the density of a substance if the mass is 354g and the volume is 243 mL?

10. Pure lead has the density of 11. 34 g/mL
Pure lead has the density of g/mL. What is the mass of a piece of lead that was placed in a graduated cylinder and the water level rose 5.00 mL?

11. A 34.6g piece of gold was placed in a graduated cylinder containing 25.0 mL. The water rose to 27.4 mL. What is the density of the gold? Is the gold pure if the actual density of gold is 19.3 g/mL?

12. The density of copper is 8.96 g/mL. What is the volume of 19.2g?