1
Separating Mixtures
1.
What is left behind when seas dry up?
Salt
2.
What is the chemical name for salt?
Sodium Chloride.
3.
What is the chemical symbol of chlorine?
Cl.
4.
What is chlorine used for in daily life?
Make drinking water safe.
5.
What kind of salt is used on the roads in winter to melt ice?
Rock Salt.
6.
What is rock salt a mixture of?
Salt, Clay and dirt.
7.
What is the difference between stalactites and stalagmites?
Stalactites: Formed by seeping of water.
Long and Pointed.
Hang down from a cave roof.
Stalagmites: Formed by tripping of water.
Short and Slow growth.
Grow on cave floor.
8.
What is left when cave water is boiled?
Limescale.
9.
What is meant by petrifying springs?
Contain water in them that contain calcium carbonate which forms limestone.
10.
Why do soft absorbent materials work best in petrifying springs?
They absorb water.
11.
What chemical compound is found in different types of sugar?
Sucrose.
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12.
Do all types of sugar dissolve in water at the same speed?
No.
13.
What is the link between solubility and temperature as by the data for sucrose?
The solubility of sucrose rises when the temperature rises and the solubility decreases
when the temperature decreases.
14.
Explain the connection between the energy of water particles at higher
temperatures and the resulting of solubility of sucrose.
At high temperature the particles move far away and other particles can dissolve.
15.
What is meant by the term soluble?
Dissolvable.
16.
What is the result when metals dissolve in each other? Give examples.
Alloy. For eg: bronze or brass
17.
What was Sullivan’s Amalgam made from?
Copper dissolved in mercury.
18.
What do dentists use now days for filling of the teeth and why?
Ceramics as they are less harmful.
19.
What are some of the different colors of rock salt?
Brown, red or yellow.
20.
What causes the different colors in rock salt?
Clay mixed with salt.
21.
Why isn’t the mined salt pure?
Maybe it contains harmful microbes or impurities.
22.
The rock salt contains both particles of salt and particles of sand and clay. Use
the particle theory to explain your observations on stirring the salt with water.
I observed that sand and clay settled at the bottom but salt mixed with water.
23.
How is salt obtained from the seawater?
Tap the seawater in ponds and as the water evaporated it left salt behind.
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24.
What is meant by the term solvent?
Let other substances dissolve.
25.
What are some solvents? Name them.
Water and Alcohol.
26.
What is meant by the term insoluble?
Can’t dissolve.
27.
Why might the purified salt still not be safe to eat?
It still might contain harmful microbes and substances.
28.
What is graffiti?
Pictures and letters made on the wall which are for making it look good.
29.
Why can’t graffiti be simply washed away with water?
Spray paints are not soluble in water.
30.
Why water is called the universal solvent and what is meant by this term?
It can dissolve anything.
31.
What happens when sugar is stirred with water?
It dissolves with water.
32.
What do we call the liquid that dissolves things?
Solvents.
33.
How do we know that sand is insoluble when we see sand on the beach?
When the ways of water come it does not mix with water.
34.
What is the soluble part of rock salt? Name it.
Salt.
35.
What is meant by the word condense?
Cool down.
36.
What hazard might be there in using solvents other than water?
Might be good but dangerous at they might be flammable.
37.
Why might there be a problem in removing tar from a car?
It is insoluble in water and acetone is needed to remove it.
38.
What is meant by distillation?
Purifying a liquid by cooling or heating.
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39.
How many changes of state are involved in distillation?
Two changes; First some liquid must be evaporated by heating and then vapors cool
down and condense back to liquid.
40.
What is distilled water?
Pure water.
41.
What were the scientists in Greece two thousand years ago called?
Alchemists.
42.
What did these scientists in Greece invent?
A way to distil liquids.
43.
What is a vapor?
A substance diffused in air.
44.
What is meant by the term malleable?
Can be drawn or cut into different shapes.
45.
Which metal is very malleable?
Copper.
46.
What is meant by the statement that copper does not corrode easily?
Does not break or bend easily.
47.
Why copper is a good choice for distillation apparatus? Give two reasons.
Conducts heat.
48.
What is the main problem with using a simple distillation apparatus, a glass tube?
Loses much steam.
49.
What happens inside a condenser?
When you put the water inside the flask and heat it, it starts to boil and the hot vapor
flows through the inner tube while in the outer tube cold water is running which cools
and condenses the hot water and starts dropping out. Cold water must be kept running so
the hot water condenses.
50.
What is meant by desalination?
Remove salt from water.
51.
What is the boiling point of water?
100oC.
5
52.
What is meant by salinity of seawater?
How much salty is the water or how much salt it contains.
53.
What happens to the salt when water freezes?
The salt is no longer present in the freezed water but makes the unfreezed water more
salty.
54.
What happens to boiling point of water at low pressures?
Water boils more easily at low temperature.
55.
Which has the higher boiling point, alcohol or water?
Water.
56.
Why is the boiling point of water about 50 higher than normal when measured at the
base of a deep coal mine?
57.
Is black ink a single color or something else?
It is a mixture of colours.
58.
What material is needed to separate the colors in ink?
Filter paper and water.
59.
What happens to black ink in chromatography?
The colors appear which were mixed to make black color.
60.
What is the name of the paper with the pattern of color spots in chromatography?
Chromatogram.
61.
What is meant by chromatography?
Method to separate soluble substances.
62.
What is chromatogram?
The resulting pattern of colours.
63.
Complete the following table by writing the correct solvent with the items it can
dissolve and whether the solvent burns or not.
Solvents
Things solvent can dissolve
Solvent burns?
Water
Sugar, Food Colors
No
Alcohol
Ballpoint pen ink, perfume, herbs & spices
Yes
6
1Q.
Acetone (Propane)
Nail Polish
Yes
White spirit.
Grease, oil paint
Yes
Complete the following table by writing the correct description to the words
provided.
2Q.
Words
Descriptions
Correct Descriptions
Evaporation
Very Soluble
Change of state
Alcohol & Acetone
Solution Mining
Solvents
Sugar
Change of State
Very Soluble
Salt is extracted by
Solvents
Solution Mining
Use the information in the following table to answer the following questions
about chromatography experiment.
Sample
Pattern on the Chromatography
Black ink A1
Yellow & Blue
Black ink A2
No pattern seen
Black ink A3
Blue & Yellow
Black ink A4
Yellow, Green, Dark Blue
a) Which of the inks is soluble? Explain your answer
A1, A3, and A4.
b) Which inks were probably the same, and what extra information is needed to be
certain of the answer to this question?
A1 and A3.
3Q.
Complete the following table by writing the correct separation technique for the
mixtures.
Mixtures
Separation Techniques
Sand from Salt
Filtration
Water from Ink
Distillation
Colors in Ink
Chromatography
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Salt from Seawater
4Q.
Evaporation
Complete the following table by writing the correct order for separating of pure
water from sea water.
5Q.
List
Steps
Collection
Collection
Condensation
Heating
Evaporation
Evaporation
Heating
Condensation
State whether the statement is true or false. If false then rewrite it correctly
a) Both salt and sugar dissolve in water. True
b) Steam and water contain the same chemical material. True
c) Breathing on a mirror shows that gases can condense. True
d) Chromatography is used to separate insoluble solids. False
e) Sand is insoluble in water. True
f) Water is not a solvent. False
g) Fine sugar dissolves at the same speed as sugar lumps. False
h) Separating dyes into colors is called chromatography. False
i) Police scientists use chromatography to solve crimes. True
j) In distillation there are two changes of state. True
k) Distillation separates mixtures of liquids according to their colors. False
l) Water and alcohol boil and fixed temperatures anywhere on Earth. True
m) The Liebig condenser uses a jacket of cold water to condense the vapor. True
n) Solubility trends are shown clearly by solubility graphs. True
o) Salt can be extracted by solution mining. True
p) Brine is a solution of water and ink. True
6Q.
Read the sentence below, and fill in the blanks using the words give below.
Rock salt is stirred with water and filtered; the liquid is collected in a basin.
Residue
Solute
Solution
Solvent
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a) The material left in the filter paper is residue
b) The salt is the solute
c) Water is the solvent
d) In the basin is the solution
7Q.
Use the words listed below to fill in the blanks
Colors, Condense, evaporates, insoluble, soluble
a) Water disappears from a puddle on the floor because it insoluble
b) We use to chromatography to separate colors.
c) Some paints are completely soluble in water.
d) Water vapor can condense on the inside of a cold tube in a condenser.
8Q.
Fill in the blanks
1. There are
of
2. Useful
can be made from salt.
3. We can make
4.
hidden underground all over the world.
gas from salt.
is just salty water.
5. Salt is
6.
in water.
caves are amazing places as there are
growing
down from the cave roof.
7. When sea water drips from the end of stalactites, and drips of water hit the cave
floor,
grow upwards.
8. The chemical formula for calcium carbonate is
9.
forms limestone.
10. Another name from common sugar is
11. Dentists used to use
alloys for filling in teeth.
12. The salt from mines is not
13. Clay is not soluble
14. Rock salt contains
15.
particles including
in Britain trapped seawater in
evaporated
countries like
and
ponds; as the water
crystals were left behind. The same method is still used in
and
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16. We can purify Rock salt on our own by using the method of
17. Acetone is also called
18. Water has been called the
19. Almost all
20. The
solvent.
and
are soluble in water.
can dissolve the colors, flavors, and
21. Alcohol
to make a product.
easily.
22. When roads eventually wear out, hot
which is
in water is
spread followed by the rock
23. Copper does not
24.
easily whereas iron does and gets
in France, is
25. Patterns of spots on the paper are called
highest mountain.