NaMe..:
HOW CAN WE SEPARATE
MIXTURES?
17
dissolve:
to make solid matter disappear in a liquid
AIM
17
How can we separate
mixtures?
When you separate a mixture, you just separate the parts.
You do not separate the linked-up atoms. Mixtures are separated
without any chemical reaction.
There are many different kinds of mixtures. Different
mixtures are separated in different ways. There are four main
ways to separate a mixture: by straining, by using a magnet, by
evaporation, and by dissolving.
STRAINING: Straining separates matter by size. A strainer has
holes. Any matter that is smaller than the holes passes through
the holes. Anything larger than the holes stays in the strainer.
Strainers come in different sizes-some
have large holes, some
have small holes.
Filter p(lp(~r is a kind of strainer. Fi llur paper has very tiny
holes. It separates tiny pieces of sol ids from the liquids they
are mixed with.
MAGNET: A magnet separates
iron parts from a mixture.
EVAPORATION: In some mixtures, a solid is dissolveu in a
liquid. Think of sugar and water. In water, sugar seems to disappear. The sugar dissolves. Not all solids dissolve in liquid.
Think of sand in water. Does sand dissolve in water?
If the liquid evaporates. the solid will appear. The solid
will not evaporate. The liquid will evaporate faster with heat.
DISSOLVINC: Some mixtures must be dissolved before they
can be separated. Wat(!r or another liquid is added.
NAME
104
~---
livr:
of Ill(! p ir.turus 1J(:Iowshow
step needed before separation
iI
tu ixt nrn I)(!illg s(!parawd. Till!
call he
(lllli'l i
,LI'I,i.
'.'
uwx
d
dOIH!.
Look at each picture. Then answer the questions on the next page. Write the letter of t he
right picture for each question.
~
mixtu re of suga~'
and sand
muddy water
1
I
water
A.
B.
c.
E.
F.
salt water
a
a fl!w days
lau~r
h
D.
105
I.
2.
xhuw
a)
Which
pi(:llIn~s
Sll'dillillg?
h)
Which p irl un: shows filter papl!r h(!illg US(!I!'r
a)
Which pir.lur« shows pi(!c(!s of iron Iwing sepurutnd?
b)
What is being used to separate the iron'? .
3.
Which picture shows dissolving'?
4.
Which picture shows evaporation?
_
_
(~OMPLF.l·IN(:J'
(..ornp I()t e
SENTENCES
Four
ways
_
IIie sen t oncos
water
air
dissolving
evaporating
heat
1.
_
WI itlI
IIW
C hoi
ou.es
straining
size
dissolve
fiIter pa per
to separate
mixtures
Iie Iow.
iron
using a magnet
strainer
holes
are:
. and
2.
Straining
separates
matter according
:1.
J\
4.
J\ strainer
5.
We can separate
6.
We use a magnet to separate
7.
\'\'hnn water evaporates,
H.
1\
sopurates
to
matter by sizo.
has many
solid that
S()()IllS
a mixture
of very tiny solid
pieces
and
water
by
using
from a mixture.
the vapor escapes into the _.
.._.
to disapp()ar in a liquid is said to
n. TIll! liquid that d ixsolvus more solids than any other liquid is
10.
J\ liquid will nvaporutu faster with
N .\r-..II·:
lOG
_
MATCHING
I';(II;/t
PIECES AND STRAINERS
l/t(~s(~ g/(lss(~s /to/ds
0/
w(ll(~r
(llId solid
"WCl~S.
..
, '
:_ '" ~ " ...: ,
.
~ ~ ~ ••.•
~ ,'""
~
.......
..:..
..-+ !.•
~
,_~:
'.
A.
'
_<
...
c
B
A
Eor.h of thcs(~
,------
IS
(J
SCrC(~11
stroillcr.
,-----------------~
- - ----------
1-1-+--- ---
--
--
- ---
-
-- _=J_~~~_,-_J
'-----1
4
How To Do This
1. Use your metric ruler to measure one of the solid pieces in each of the glasses.
2.
Measure the width of olle of the openings
3.
Choosing from thn lisl below. wr ito Oil tho provided
solid
in each screen strainer.
lines the measurements
of each
picco aru l SU'(!(!II opuni ng.
:l.:i
4
L 111111
:I 111111
4.:i
:i
11l11l
IIlIll
The solid
PII!C(!S III glass A measure
The solid
plI!ces ill glass
B mensurr:
The solid pJ(!U~S III glass C measure
across.
4 mm
across.
across.
5 mm
6 ____
mm
___
across.
The openings
4.5 mm
___
across.
The open ings In screen
TIll! opcniugs
:1 moasu re
in SCI'l!(!n 4 muasure
2 mm
3.5 mm
Ii III III
1lI1ll
3 mm
The openi ngs in screen 1 measure
In screen 2 measure
mm
across.
across.
107
Now, IIS(! 111f!s(!IIll!ilSllrPlllf!lIls 10 .mswnr
Iii 111f!rigid slm;lwl' I'm quusl ious 1-'1.
l hn following
quustio ns. Chonsr: the 1I11111",:r
1.
Which xl rn i nur will sl!paralo all the shown solids from till! water'!'
2.
Which strainer will separate none of the shown solids from the water'?
3.
Which is the largest strainer that can separate the solids in glass U'?
4.
Which is the largest strainer that can separate the solids in glass A'?
5.
Can any of these strainers separate salt from salt water'?
_
_
TRUE OR Write T on the line next to the number if the sentence is true.
FALSE Write F if the sentence is false.
--------------------------------------------------------------------------1.
Straining
2.
Evaporation
3.
1\ magnet caUSI!Sa physical chungo.
4.
Dissolving causes a physical change.
5.
Fi Iter paper has large holes.
6.
Only scientists
7.
When a liquid evaporates,
8.
When sugar dissolves it goes out of the water.
9.
1\ magnet can separate a mixture of paper clips and rubber bands.
1n.
\1AI\1E
lOB
causes a chemical change.
causes a chemical change.
use strainers.
Ilot water evaporates
it goes into the air.
faster than cold water.
_
HOW WOlJLD
liv«
kinds
Mixture
Mixture
Mixture
Mixture
Mixture
1
2
3
4
5
YOI/ SEPARATE
of mi xturus
(11'1:
TIIESE MIXTI JI{I':S'!
list(:d huluw.
salt and iron filings
salty water
salt, iron filings, and water
gravel, sand, and sugar
gravel, sand, sugar, and iron
filings
Can you decide how to separate tI1l:s(: mixlurns?
Bdon: making up your mind.
the diagrams.
Each diagram shows a difluront sl(!p used in separating
mixtures.
Diagram
L.......
()iagralll
1\
study
H
_
1\ Illaglwl
Wall:r is usnrl
is lIs(:d 10 s(!paral(! iruu.
Iliagralll
10 d isxnlvn
a solid.
(:
1\ st ru iner is Ils(!d to s(:parale: large: solids.
I()! I
----
Evaporation
is used
dissol ved solids.
to separate
already
Filtration
solids.
----
- --
-
is used to separate very small
Now decide which step or steps are needed 10 sopuruto mixtures 1 through !'i. In the blank
spaces below, write the diagram letlers (A, B, C, I), or E) of the steps you would use.
Mixture 1. salt and iron filings (only one step is needed) ..
Mixture 2.
salty water (only
Mixture 3.
salt, iron filings, and walnr (two slt~ps aru Iw(~d(~d)
Mixture 4.
gravel, sand, and sugar (four steps are neodud)
------
Mixture 5.
NAME
110
OIW
slup
is Iw(~dnd)
----_ ...._-
gravel, sand, sugar, and iron filings (five steps are needed)
_