Question

83
Is Matter Around Us Pure
How much water should be added to 158
of sugar to obtain 15% sugar solution?
It 25 mL of acetone is present in 250
mL of its aqueous solution, calculate the
concentration of the solution
A solution has been prepared by dissolving
40g of common salt in 460g of water.
Calculate the mass percentage of this
10
7
a
11
solution
S
During an experiment, the students were
asked to prepare a 20% (Mass/Mass)
solution of sugar in water. Aalia dissolved
20 8 of sugar in 100 g of water while
Sarika prepared it by dissolving 20 g
of sugar in water to make 100 g of the
solution
b
Are the two solutions of the same
concentration?
Compare the mass % of the two
solutions
9. Rohan tested the solubility of three different
substances at different temperatures and
collected the data as given below (results
are given in the following table, as grams of
substance dissolved in 100 grams of water to
form a saturated solution).
Find the solubility of each salt at 283 K.
Which salt has the highest solubility at
this temperature?
Colloidal solution appears to be
homogeneous but actually it is
heterogeneous.' Justify this statement
When a fine beam of light enters a room
through a small hole, Tyndall effect is
observed. Why does this happen? Give
one more example where this effect can be
observed
12. Draw a flow chart to indicate the separation
of constituents of mixtures containing
ammonium chloride, sand and iron filings.
13. Explain the steps to separate pure crystals
of copper sulphate from an impure sample?
14. Crystallisation is a better technique than
simple evaporation technique. Justify this
statement by giving two reasons.
15. When do we use the process of
centrifugation? State the principle involved
in this process. List any two applications of
this process in day-to-day life.
16
a. Name a technique to separate a
mixture of two or more miscible liquids
for which difference in boiling points is
less than 25 K.
b. Describe the structure of the column used
in the above technique. Why is it used?
17. With the help of a flow diagram,
illustrate the process of obtaining
different gases from air. If the boiling
point of oxygen, argon and nitrogen
are -183°C, -186°C and -196°C,
respectively, which gas gets liquefied first
as the air is cooled?
18. What is chromatography? Explain the
process
19. Differentiate between
a. Physical and chemical changes
b. Mixture and compound
TEMPERATURE (IN K)
SUBSTANCE
DISSOLVED
283
293
313
333
353
36
36
36
37
37
35
35
40
46
54
Sodium chloride
Potassium chloride
Ammonium chloride
24
37
41
55
56
a
What mass of sodium chloride would
be needed to produce a saturated
solution of sodium chloride in 100
grams of water at 333 K?
b. How much of potassium chloride is
required to prepare a saturated solution
in 50 g of water at 293 K?​

Answer 1

Answer:

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