# Which has more mass? A) 1 kilogram of feathers B) 1 kilogram ... Which has more mass? A) 1 kilogram of feathers B) 1 kilogram of bricks They are the same! 1 kg = 1 kg Which takes up more space? A) 1 kilogram of feathers B) 1 kilogram of bricks The Feathers Measure matter by finding the density!

Which has the greater density? A) steel paper clip B) steel bar The density of steel is the same! Size doesnt matter! Density of Steel steel bar Units for Density

Metric Units: Solid: g/cm3 Liquid: g/mL Memorize This! Density of water is 1g/mL (at 4 C) Which one floats? Why? Density of Water:

1.00 g/mL Density of Ice: 0.92 g/mL Which of the following will float on water? Why is it good to know the density? Density helps you identify a substance All those less

than 1.0 g/mL Predict the correct floating order of the substances as they would appear in the Density Column. Substance Density g/cm3 Copper 8.8 Corn oil

0.925 Corn syrup 1.38 Glycerin 1.26 Mercury 13.6

Plastic 0.93 Rubber 1.34 Tar 1.02 Water

1.00 Wood 0.7 Specific Gravity Specific Density of Substance Gravity (g/cm3) = Density of Water (g/cm3) Specific gravity is the same as the density except: There are no units! Why? Because they cancel!

Ex: Density of water: 1 g/cm3 Specific Gravity of water: 1 (no units!) What is the specific gravity? It is the same as the density but it has no units! Calculating Density Obtain mass using a balance. Obtain volume by any of these methods. Ruler: Volume = L x W x H Graduated cylinder Water displacement

m Magic Circles d v d = m/v m=dxv v = m/d 1) Is the bar really gold or fools gold? Find the density of the bar if the mass is

1891.4 g and the dimensions are 3.5 cm by 3.5 cm by 8.0 cm. Gold has a density of 19.3 g/cm3 V=LxWxH D = M/V 1891.4 g / 98 cm3 = 19.3 g/cm3 Yes its gold! What is the Specific Gravity?

m d v 2) Is this liquid water, alcohol, or kerosene? Find the density of the liquid if the mass is 16.98 g? Water 1.0 g/mL Alcohol 0.79 g/mL Kerosene 0.82 g/mL Read the volume

D = M/V 16.98 g / 21.5 mL = 0.79 g/mL It is alcohol! What is the Specific Gravity? m d v

3) Is the Silver Surfer really made of silver? We obtained a sample with a mass of 262.5 g. Platinum 21.5 g/cm3 Silver 10.5 g/cm3 Tin 7.3 g/cm3 Find the volume by water displacement. d = m/v = 262.5 g / 25 cm

3 m d v = 10.5 g/cm It is Silver! 3 4) What is the volume in mL of this syrup if it has a density of 0.63 g/mL and a mass of 78 g?

v = m/d = 78g 0.63 g/mL = 123.8 mL m d v 5) What is the mass in grams of this lead pipe if it has a density of 11.4 g/cm3 and a volume of 55 cc?

m=dxv = 11.4 g/cm3 x 55 cc = 627 g m d v