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Separating Mixtures. http://www.youtube.com/watch?v=jWdu_RVy5_A. The components of a mixture can be separated based on the physical properties of: Magnetism Density
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Separating Mixtures http://www.youtube.com/watch?v=jWdu_RVy5_A • The components of a mixture can be separated based on the physical properties of: • Magnetism • Density • An instrument that uses this property to separate mixtures when tiny solid particles are dissolved in a liquid is called a centrifuge. • Some techniques used to separate the components of a mixture are: • Filtration • used to separate liquids from solids • Evaporation or distillation • used to separate solutions Episode 203
Density • Mass per unit volume • Per means “divide” • Density = mass/volume • Common units for density: • g/mL • g/cm3 Episode 203
Suppose we have an object with a mass of 5.0 grams ans a volume of 2.0 mL. What would the density of this object? 5.0 grams 2.0 mL 2.5 grams/mL Episode 203
Problem Set One • Given a mass of 12 g and a volume of 3 mL, calculate the density. • What is the mass of 50 mL of water? (Density of water is 1 g/mL) • Given that the density of iron is 7.9 g/cm3, what would be the volume of a 15.8 g piece of iron? 12 grams = 4grams/mL 3 mL m = Dv = 50 grams 1 g/mL x 50 mL 15.8 grams v = m/D = 2.0 cm3 7.9 g/cm3 Episode 203
Problem Set Two • Find the density of a block with a length of 4.0 cm, a width of 3.0 cm, a height of 2.0 cm, and a mass of 36 grams. • Find the density of an 8.0 g rock if the water in a graduated cylinder rises from 20.0 mL to 23.5 mL when the rock is placed into the cylinder. • You have a piece of silver with a mass of 31.5 g. Silver has a density of 10.5 g/cm3. What would be the new level of water if this piece of silver is placed into 15 mL of water? 36 grams = 1.5 grams/cm3 4.0cm x 3.0cm x 2.0 cm 8.0 grams = 2.3 grams/mL 23.5mL – 20.0mL 31.5 grams v = m/D = 3.00 cm3 or 3.00 mL 10.5 g/cm3 15 mL + 3.0 mL = 18mL Episode 203