1. Density
All substances have different densities, therefore, you can identify a substance if you know its density
The formula to calculate something’s density is:
When we calculate density, the units we use are either g/mL or g/cm3. How do we know which set of units to use? M D V

2. g/ml - liquids g/cm3 for solids
volume of liquids are measured in milliliters
g/cm3 for solids
Volume of solids are measured in cm3

3. Mass To find mass, we put the object on a balance
Mass is always in grams
How do we find volume?

4. Volume - two options Liquids Solids
Use a graduated cylinder to find the volume in mL
Solids
If possible, measure length, width, and height; then multiply to get your volume in cm3
If not, use displacement of water to measure volume (you will need to convert to cm3 when you are done because it is a solid)

5. Measuring Solid Volume
10 cm
9 cm
8 cm
We can measure the volume of regular object using the formula length x width x height.
_____ X _____ X _____ = _____
We can measure the volume of irregular object using water displacement.
Amount of H2O with object = ______ About of H2O without object = ______ Difference = Volume = ______

6. Calculate the volume:

7. Water What is the density of water?
Now you know how to find mass and volume, you can find the density of objects.

8. Practice 1
V = 15 mL
M = 45 g
D = ?
D = m/v
D = 45 g/ 15mL
D = 3g/mL

9. Practice 2
V = 10 mL
M = 100 g
D = ?
D = m/v
=100 g/10mL
D = 10 g/mL

10. Practice 3
V = 17 mL
M = 34 g
D = ?
D = M/V 34 g/ 17 ml
D = 2 g/mL

11. Practice 4
M = 45 g
D = 9 g/cm3
V = ?
V = m/d 45 g/ 9 g/ cm3
V = 5 cm3

12. Practice 5
M = 144 g
D = 12 g/cm3
V = ?
V= m/d 144 g/12 cm3
V = 12 cm3

13. Practice 6 M = 27 g D = 108 g/cm3 V = ? v = m/d 27 g/ 108 g/cm3
V = .25 cm3

14. Practice 7 D = 12 g/mL V = 3 mL M = ? M = d x v 12 g/mL x 3 mL
M = 36 g

15. Practice 8 D = 1445 g/mL V = 2 mL M = ? M = d x v 1445 g/mL x 2 mL
M = 2890 g

16. Practice 9 D = 3.54 g/mL V = 22 mL M = ? M = d x v 3.54 g/mL x 22 mL
M = g