Separation of Mixtures Review

Test your separation of mixtures memory by trying the activities below:

What do you do when you don’t know a conversion factor between the two units in the problem?
make something up
give up and take a nap
use multiple conversion factors
change the problem
A(n) ______ is made of two or more elements chemically combined.
element
mixture
compound
alloy
What is the basis for separating mixtures using a centrifuge?
magnetism
boiling points
densities
filtration
Which technique or property would be used to separate aluminum cans from steel cans?
magnetism
boiling points
densities
filtration
What is the formula for solving a density problem?
D = m x v
D = m / v
D = v / m
What would be the density of a ten gram object that displaces two milliliters of water?
5
20
5 g/mL
20 g/mL
Would an eight gram object with a length of 4 centimeters, a width of 2 centimeters, and a height of 2 centimeters, float or sink in water?
float
sink

Density Problems

Click on the words Hint and Answer to check your solution.

Given a mass of 14 g and a volume of 28 mL, calculate the density.

Hint

D= m/v

Answer

D = m/v = 14 g/28 mL = 0.50 g/mL

What is the mass of an object with a density of 4.0 g/cm3 that displaces 3.0 cm3 of water?

Hint

m = DxV

Answer

Given that the density of iron is 11.35 grams per centimeter cubed, what would be the volume of a 1.1 gram piece of iron?

Hint

v = m/D

Answer

V = m/D = 1.1 g/(11.35 g/cm3) = 0.097 cm3

Find the density of a block with a length of 8.0 cm, a width of 4.0 cm, a height 2.0 cm, and a mass of 32 g. Would this block float or sink in water?

Hint

D = m/v ; Density of water is 1 g/cm3

Answer

Density of block is D = m/v = 32 g/(8 cm x 4 cm x 2 cm) = 32 g/64 cm3 = .5 g/cm3; Density of block < density of water: block would float

You have two pieces of jewelry. One of them is supposed to be pure silver. The first piece has a mass of 20.0 g and the other piece has a mass of 44.0 g. Both pieces displace 4.0 mL of water. Silver has a density of 10.5 g/cm3. Which piece is actually silver?

Hint

D = m/v

Answer

20/4 = 5 and 44/4 = 11 If one has to be silver, it’s likely the second one.

 

 

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