Extra question of chapter is matter around us pure
Answers
Answer: only 10 Question
Explanation:Question 1.Write your observation when the following processes take place:
a. An aqueous solution of sugar is heated till it gets dried up.
b. A saturated solution of KCL at 60° C is allowed to cool at room temperature.
c. A mixture of iron filings and sulphur powder is heated strongly.
d. A bean of light is passed through colloidal solution.
e. Dilute HCI is added to mixture of iron filings and sulphur powder.
a.When an aqueous solution of sugar is heated to dryness, the sugar will be left behind in the container after the vaporization of water.
b. we would observe crystals of potassium chloride being formed in the liquid solution
c. Iron Sulphide(FeS) will be formed
d. The light is scattered and it is called tyndall effect
e. It will separate S and Fe, to form H2SH2S gas and iron chloride(FeCl2FeCl2)
Question 2.what is chromatography? How will you separate the components of black ink using chromatography? Write any two applications of chromatography.
Question 3.(a) You are given a mixture of sand, water and mustard oil. How will you separate the components of this mixture? Explain it with the help of different separation methods involved in it.
(b) Give flow diagram showing the process of obtaining gases from air.
Question 4.
A.Which of the following are chemical changes and physical change?
(i) Decaying of wood
(ii) Sawing of wood
(iii) Burning of wood
(iv) Hammering of a nail into a piece of wood
B.We know that Tincture of iodine has antiseptic properties. This solution is made by dissolving
(a) iodine in alcohol
(b) iodine in vaseline
(c) iodine in H20H20
(d) iodine in KIKI
A. Chemical change : (i) and (iii)
Physical change: (ii) and (iv)
B. (d)
Question 6.Give two examples from daily life where Tyndall effect is observed.
Question 7.Identify homogeneous and heterogeneous mixtures among the following:
Air, salt solution, kerosene in water, muddy water, soil, soda water
Question 8.Three students A, B and C prepared mixtures using chalk powder, common salt and milk respectively in water. Whose mixture:
a)Would not leave residue on filter paper after filtration?
b)Would show Tyndall effect?
c)Would give transparent/ clear solution?
d)Would settle down at the bottom when left undisturbed?
e)Could be filtered by filter paper?
a) Mixture done by B will not leave any residue as salt solution is a true solution.
b) Tyndall effect will be shown by milk solution of C. It's a colloidal solution. So it shows tyndall effect.
c) Salt solution will obviously be the clear solution. So, again its B.
d) Chalk powder mixture of A will settle down when left undisturbed as the particles are too heavy to resist gravity.
e) Again, Chalk powder of A can be filtered by filter paper. Although, it is possible to filter milk solution of C also, if sufficiently micro-porous filter is used.
Question 10.How will you separate a mixture of red and blue inks? Name the technique used. Draw a labeled diagram and explain it.