SEPARATION, PURIFICATION, AND ALTERATION OF

SUBSTANCES

A. Objectives

1. To separate the components of the mixture based on physical differences.

2. To purify liquid solvent by distillation.

3. To show the changes in physics and chemical changes.

B. Theory

Chemistry is an experimental science. But if our experiments are to be reproducible, we must

be able to describe fully the substances we’re working with— their amounts, volumes,
temperatures, and so forth. Thus, one of the most important requirements in chemistry is that
we have a way to measure things.

The mixture can be separated into its constituent components based on differences in physical
properties such as size, grain, boiling point, solubility, magnetism, etc.

If two or more substances mix with each other in such a way that the substances can still be
separated again physically, then a mixture is obtained. Mixtures can also involve constituents
which can interact with each other and constituents which do not interact with each other.

Chemistry is the study of matter and the changes it undergoes. Chemistry is often called the
central science, because a basic knowledge of chemistry is essential for students of biology,
physics, geology, ecology, and many other subjects. Indeed, it is central to our way of life;
without it, we would be living shorter lives in what we would consider primitive conditions,
without automobiles, electricity, computers, CDs, and many other everyday conveniences.

1. Separating a mixture of two solids.

Sugar is soluble in ethanol, while salt is insoluble. When a mixture of sugar and salt is mixed
with ethanol, the sugar dissolves while the salt does not. When the mixture is filtered, the
undissolved salt remains as the residue in the filter. The filtrate, sugar solution, passes
through the filter. If the filtrate is left open to the air, the ethanol evaporates, and solid sugar
remains.

2. Distillation

a. Simple distillation

Distillation is a process in which a mixture of materials is heated to separate the components.

Simple distillation is used when the boiling points of the components are widely separated. In
the diagram, salt water is placed in a round-bottom flask. Water boils at 100°C and becomes
water vapor. A condenser consists of an inner tube surrounded by a jacket of cold water.
This jacket ensures that the inner tube remains cool. The vapor passes into the condenser,
where it is cooled and changes back into liquid. The water runs out of the condenser and is
collected in a second flask. The salt remains in the round bottomed flask.

b. Fractional distillation

Fractional distillation is used to separate components whose boiling points are similar.
Ethanol boils at 78°C and turns to vapor. Because the boiling point of water is only 100°C, a
significant amount of water also becomes vapor as a result of evaporation. The fractionating
column contains glass beads, which provide a large surface area for vapor to condense and
the resulting liquid to subsequently boil. As the vapor mixture moves up the fractionating
column, it condenses and then boils again to become vapor. Each time, the proportion of
ethanol in the mixture increases.

3. Paper chromatography

Chromatography is a technique for separating and identifying mixtures of solutes in

solutions. In paper chromatography, absorbent paper is suspended on a support so that only
the bottom rests in the solvent. A base line is drawn in pencil above the level of the solvent.
(If ink were used, the dyes in the ink would separate during the process and mix with the
sample.) A concentrated solution of the sample mixture is made by dissolving as much as
possible in a very small volume of solvent. A small amount of the concentrated solution is
spotted onto the base line. The chromatography paper is suspended over the solvent. The
solvent rises up the chromatography paper.

C. Equipment and Materials lab

equipment :

1. Spiritus burner

2. Glass pipe

3. Test tube

4. Tube clamp

5. Evaporation dish

6. Distillation set

7. Tricycle

8. Asbestos gauze

9. Metal spoon

10. Beaker 50 ml

11. Erlenmeyer flask

12. Chromatographic bottle as high as 12 cm

13. Funnel

14. Stirring rod

Materials Lab

1. Candles

2. Mg band

3. Nichrome wire

4. Sulfur

5. Dirty salt

6. Filter paper

7. Chromatographic paper

8. Blue, red and green ink

9. Boiling stones

10. Tea water

D. Methods

1. Separating of the mixture by filtering and evaporating.

a. Putting a teaspoon of dirty salt b. Folding filter paper into a cone

in a beaker containing 10 ml of shape, insert into the funnel, damping
water, stirring until all the salt has filter paper with a little water so that
dissolved. the paper adheres to the funnel.

c. Straining the solution and

collect the filtrate in a clean
beaker. d. Taking 5 ml of filtrate and
entering into the evaporation dish.
Heating the dish until all the
water runs out.
2. separating by paper chromatography.

b. Putting water into a 1 cm tall

a. Providing chromatographic
beaker. then roll the top of the
paper size 12x4. Drawing a line
chromatography paper on the
using a pencil at a distance of 1
stick and hang the paper
cm from the bottom edge of the
perpendicular to the bottle. the tip
paper. then make a dot with green
of the paper must be dipped in
ink in the middle of the line.
water, but the ink dots should not
making dots with other ink colors
be dipped.
on the left and right of the green
dot with a distance of 0.75 cm. let
the green ink dry.

d. Measuring the distance c. Allowing ink to creep up on

between the water level and the chromatographic paper. with
distance of each color mark from water, the color zart in the ink
the pencil line at the bottom end will also go up. if the water has
of the filter paper. calculate the crept closer to the line at the top
price comparison of the two end of the paper, remove the
distances for each stain. paper and mark the boundary of
the creeping water, let the
chromatographic paper dry. notice
the ink color stains.
3. Distillation

a. Fill the distillation flask in half b. Arranging the tool as shown.

with tea water. Putting some
boiling stones in it.

c. Run tap water through the

liebig cooler.

e. compare the initial tea water d.Heat the distillation flask until
with the distillate the water boils, observe the
temperature rise on the
thermometer. also observe the
4. Substances changes

a. Light a candle and observe a b. Insert a clean glass pipe for a

burning candle. few seconds into the flame of the
candle.

d. Pin the Mg band with pliers c. Insert a clean glass pipe for a
and insert the tip into the few seconds into the liquid at the
flame .until it glows. bottom of the candle.

e. Insert the nichrome wire into f. Put a little bit of sulfur on a

the flame until it glows. metal spoon and heat it up.
E. Experiments Data and Calculation

1. Separating of the mixture by filtering and evaporating.

a. The color of dirty salt before mixed with water is brownish white.

b. The color of the dirty salt solution and water is turbid.

c. The color of the substance left on the filter paper is brown.

d. The color of the filtrate after filter paper is clear and clean.

e. The solid left on the dish after evaporation of the filtrate is pure white salt.

f. The ratio of the color of dirty salt to the solids left on the evaporation dish is salt that have
been evaporated have more clean and clear salt, and also more white than the salt before
(dirty salt)

2. separating by paper chromatography.

Stain
Ink Color Stain Color
Distance
Blue Ink 1. Dark Blue 6 cm
2. Light Blue 6 cm
1. Blue 6.5 cm
Green Ink 2. Yellow 4.5 cm
3. Green 5.8 cm
1. Red 5.4 cm
Red Ink 2. Pink 3.5 cm
3. Yellow 5.5 cm

3. Distillation

a. The difference between distillate and liquid before being distilled is clear distillate while
undistilled liquid is brown.

b. distillate boiling point

94 ° = droplet 1

96 °=¿ droplet 2

100 °=¿ more droplet

4. Substances changes

a. Burning candles: candles that were originally dense and then burned turn to liquid at cold
temperatures back to solidify
b. The glass pipe after being put into the flame of the candle is the part that is hit by a black
flame

glass pipe after being inserted into the liquid under the flame of the candle is the part that is
affected by the white liquid substance which is formed is melted wax which solidifies due to
cold temperatures.

c. Mg ribbon burning: lights up / turns white and then turns to white colored ash and chemical
changes occur

d. Nichrome wire combustion: red-glowing, after being black and not glowing

e. Heating sulfur with a metal spoon: solid sulfur is then heated to a yellow liquid which
forms sticky and sticks to the metal spoon

F. Result and Discussion

1. Separating of the mixture by filtering and evaporating.

In this experiment there was only a physical change because there was only a change in form
without changes in the structure and properties of the salt, the change was from solid to
liquid, then from liquid to solid.

2. Separating by paper chromatography.

Chromatography is a molecular separation technique based on the different patterns of

movement between the mobile phase and the stationary phase to separate the components (in
the form of molecules) that are in solution. Molecules that are dissolved in the mobile phase,
will pass through the column which is the stationary phase. Molecules that have strong bonds
with the column will tend to move more slowly than molecules with weak bonds. With this,
various types of molecules can be separated based on the movement of the column.

in the chromatography there is a physical change because the ink has only a color separation,
without forming new substances.

3. Distillation

distillation is the process of separating two or more compounds in a mixture by using

different volatility properties (the tendency of a compound to change form from liquid to gas)
from the elements of the mixture.

The definition of distillation here refers to the process that will take place, namely the change
from liquid to gas (evaporate) and change from gas to liquid (condensation).

All processes that occur in distillation are physical changes, without involving chemical
reactions.

4. Substances changes
a. The candles that light up will melt over time, this is because the wax is exposed to heat
from burning the wick, in this experiment the shape changes from solid to liquid, and after a
while the liquid wax will harden again, in this experiment there is a change in physics.

b. In an experiment inserting a glass pipe into the flame of a candle, the glass pipe which was
originally clean turns black, this occurs because the burning axis produces charcoal attached
to the glass pipe, the black color is a new substance so that in this experiment a chemical
change occurs.

its chemical reaction is :

2C20H42 (s) + 61O2 (g) 40CO2 + 42H2O

c. In an experiment inserting a glass pipe into a liquid under a candle flame, the liquid is
attached to a glass pipe and after a few seconds will harden, in this case a physical change
occurs.

d. The Mg band which is silver after being put into the flame will glow brightly, then the Mg
band turns to white ash, in this case a chemical reaction occurs.

Its chemical reaction is:

Mg (s) + O2 (g) MgO(s)

2Mg (s) + O2 (g) 2MgO(s) (equal)

Gray colorless white ash
Reductant : Mg
Oxidixer : O2

e. In experiments inserting the nichrome wire into the flame, the red glowing nichrome wire,
after being picked up is black and does not glow anymore. in this case a physical change
occurs

f. During the experiment heating the sulfur on a metal spoon, the sulfur which was originally
solid turned into a yellow liquid, after a while becomes a sticky substance and attaches to the
metal spoon. in this case there is a change in physics.

G. Conclusions and Suggestion

Conclusions:

From this experiment we can conclude that changes in physics is a changes in matter that are
not accompanied by the formation of substances of a new kind and chemical change is a
change in matter that results in different (new) types and properties of matter from what was
originally called (chemical changes are also called chemical reactions or reactions).

Suggestions: for someone who will do this experiment, do it carefully and thoroughly
H. References

Derek McMonagle, 2006 : 47

Derek McMonagle, 2006 : 48

Derek McMonagle, 2006 : 49

McMurry Fay, 10

Buku Petunjuk Praktikum Kimia Dasar, 2019 : 1

Kasmadi & Gatot, 2019:2

Raymond Change, 4

I. Answer the Questions

Theoretical Preparation

Mixed separation

1. Mention the purpose of dissolving dirty salt into water?

so that it's easier during the screening process

2. What is the purpose of filtering out a dirty salt solution?

so that the dirt in the salt separates from the filtrate

3. Mention the purpose of evaporating the filtered filtrate?

in order to form clean salt crystals

4. Can separation, filtering, and evaporating work be used to separate the mixture of salt and
sugar? Yes,it can.

5. Can the mixture of water and alcohol be separated?

Can be separated through the distillation process that is the separation of the mixture based
on differences in boiling points. alcohol whose boiling point is lower than water will first
evaporate and come out as a distillate (the result of distillation).

Destillation

1. Why is the flow of water in the liebig cooler made against water distillate?

This is intended so that the temperature of the solution becomes high and the pressure is also
high, so that the steam produced a lot. The steam will be cooled and turned into distillate. If a
lot of steam is produced, then the amount of distillate produced is also large.

2. rainwater comes in part from the sea. why does it taste not salty?
because it's already condensed in the air.

Substances Changes

1. Mention the characteristics of substances undergoing physical change! give five examples
of changes in physics!

Changes in physics are changes in matter that are not accompanied by the formation of
substances of a new kind. Examples of physical changes are mixing sugar into water to form
a sugar solution, clothes originating from cloth, gravel originating from rocks after the
collision process, ice cubes originating from water, flour derived from rice.

2. Mention the characteristics of substances undergoing chemical changes! give five

examples of chemical changes!

Chemical change is a change in matter that results in different (new) types and properties of
matter from what was originally called (chemical changes are also called chemical reactions
or reactions). Examples of chemical changes are the burning of wood, rotten apples, paper
burned to ash, dry leaves that are processed into compost, burning gasoline on motor
vehicles.

3. If 6 grams of the mg band are completely burned what is the maximum mass of
magnesium oxide that can be produced?

Reaction..

2Mg + O2 ==> 2MgO

mass Mg = 6 grams

Ar = 24

mol Mg = mass / Ar = 6/24 = 0.25 mol

from the mole reaction Magnesium oxide = mole Mg

= 0.25mol

mol MgO = 0.25 mol

Mr = 40

mass MgO = Mol x Mr

= 0.25 x 40

= 10 grams

so the mass of Magnesium Oxide produced is 10 grams

Question

1. in the mixed separation experiment what is the function:

a. Adding water: To simplify the filtering process

b. Filtering: To separate residues from filtrate

c. Heating: To change liquid into solid

2. Another way (other than distillation) that can be used for purification of substances is to
recrystallize from:

a. Solution: Filtrate the dirty salt into clean salt

b. steam: evaporation

3. In substances change experiments, which experiments produced new substances?

Mg band burning, burning of nichrome wire, burning of test tubes

Documentation

Equipments and Materials lab

Experiment result