LABORATORY – Separation of a Three Component Mixture
Introduction:
In principle, any mixture can be separated by a series of procedures that rely on differences in physical
properties of the components of the mixture. For example, sand can be separated from bits of iron with a magnet
because iron is attracted to a magnet and sand is not.
In this experiment you will have a mixture of sand (silicon dioxide), salt (sodium chloride), and calcium
carbonate. Sand and calcium carbonate are not soluble in water, but salt is soluble. Calcium carbonate reacts and
dissolves in acid but sand does not (remember acids are water solutions). Water evaporates at a moderate temperature,
but sand, salt, and calcium carbonate do not. These properties can be used to separate the mixture. If everything goes
well, the mass of each component after separation will be the same as its mass in the original mixture (law of
conservation of mass). Separating the mixture will thus allow you to analyze it.
SAFETY – WEAR SAFETY GOGGLES!!
CAUTION: HOT PLATES REMAIN HOT FOR A LONG TIME
Available equipment:
Beakers
evaporating dishes
Tongs
hot plates
ring stand
oven
iron ring
spatulas
funnel
balance
filter paper
PROCEDURE:
You will write a DETAILED procedure in your lab notebook explaining, step-by-step, how to complete this
laboratory experiment.
Use about 5 grams of the mixture.
DATA:
Set up a data table.
ALL MEASUREMENTS GO IN THE DATA TABLE!!!
(this includes measurements like mass of the beaker, mass of the evaporating dish empty, mass of the
evaporating dish with salt, etc.)
No calculated values go into the data table (if you have to add, subtract, multiply or divide then the number
you get is a calculated value and it DOES NOT go into the data table)
ANALYSIS:
Calculate the mass of the mixture (show your work!!!!!)
Calculate the mass of the salt in the mixture (show how you did this – show numbers used and explain it in words)
Calculate the mass of silicon dioxide (sand) in the mixture
Calculate the mass of calcium carbonate in the mixture
Calculate the % by mass of each of the components of the mixture (i.e. what % of the mixture is sand, etc.)
Questions: (answer in complete sentences!!)
When hydrochloric acid is added to the mixture bubbling occurs. What are the bubbles composed of?
Why can’t you evaporate the liquid obtained from mixing the sand in HCl and weigh the residue to determine the mass
of calcium carbonate?
In determining the mass of calcium carbonate, what principle (law) is being used? Look this up in the textbook if you
don’t already know the answer.
Write your conclusion!