7 A 9 Mass and Density Vocabulary Mass

7 A 9 Mass and Density

Vocabulary • Mass: – How much matter is in an object • Density: – Physical property of a substance – Mass of a substance per unit of Volume – Mass / Volume, in g / m. L or g / cm 3 • Quantitative: describe with numbers • Qualitative: describe with words

Background • • Measure Mass AND Volume of a substance. Calculate Density by dividing mass by volume. Pure substances have characteristic densities. So you can use the calculated density to identify the type of material it is made from.

Data Table: Mass, Volume, Density • Turn lab book sideways and make 5 columns: 3 narrow, 1 wide, and 1 narrow • Object: (Light gray cylinder, Dark gray cylinder, Light gray bar, Dark gray bar, Light gray cube, and Dark gray cube) • Mass (g): from balance • Volume cm 3: Cylinder=6, Bar=7. 9, Cube=15. 6 • Density Calculation: M/V • Density (g/cm 3)

Procedure 1 • • • Same 6 Objects: 2 cubes, 2 cylinders, 2 bars Use a Balance to find mass to nearest 0. 1 gram Enter the Volumes from the 7 A 8 Volume Lab Calculate Densities; divide Mass by Volume Compare results with table partners. Repeat any measurements you are unsure of.

New Data Table: Density Identity • Make a new data table with 4 columns. • Object: (Light gray bar, Dark gray bar, Light gray cube, Dark gray cube, Light gray cylinder, and Dark gray cylinder) • Density calculated: copy from first data table • Closest Density from Table 3: see page A 40 • Type of Solid from Table 3: see page A 40

Table 3: Solid Material Densities PLASTICS High-density polyethylene (HDPE)-----Polystyrene (PS)----------------Polyvinylchloride (PVC)------------METALS Magnesium-------------------Beryllium---------------------Aluminum--------------------Titanium---------------------Zinc------------------------Iron------------------------Tungsten--------------------- DENSITY (g / cm 3) 0. 95 1. 1 1. 3 1. 7 1. 9 2. 7 4. 5 7. 1 7. 9 19. 4

7 A 9 Mass/Density Analysis p. A 40 On separate paper, answer each in 1 paragraph. 2) Now that you have identified each solid, look at their hazards in Table 2 on page A 31. Explain the precautions you must take for each of them. 3) A block of wood is 4 cm wide, 5 cm long, and 10 cm high. It weighs 100 g. (a) Find its volume (b) Calculate its density (c) Will it sink or float (water is 1 g/cm 3), (d) If you cut the block in half, calculate the new mass, volume, and density of each piece (e) How do new densities compare to the original?