Advertisements
Advertisements
Question
Explain why steel is used to make railway lines.
Advertisements
Solution
Steel is used to make railway lines because the particles of steel have fixed positions and show no free movement. This ensures that there will be no change in the shape of the railway lines, which makes it safe to travel.
APPEARS IN
RELATED QUESTIONS
Define matter.
Explain why, osmosis can be considered to be a special kind of diffusion. Classify the following into
(i) osmosis, and (ii) diffusion :
- swelling up of a raisin on keeping in water
- spreading of virus on sneezing
- earthworm dying on coming in contact with common salt
- shrinking of grapes kept in thick sugar syrup
- preserving of pickles in salt
- spreading of smell of cake being baked in the kitchen
- aquatic animals using oxygen dissolved in water during respiration
Name one solid, one liquid and one gaseous non-metal.
What is meant by saying that non-metals are brittle ?
Classify the following as elements or compounds :
Iron, Iron sulphide, Sulphur, Chalk, Washing soda, Sodium, Carbon, Urea
How would you confirm that a colourless liquid given to your is pure water ?
State whether colloidal solutions are homogeneous or heterogeneous.
Which of the following is a sol ?
Shaving cream, Milk, Fog, Soap solution, Hairspray
One of the following liquids will leave behind a residue on heating. This one is :
Tincture of iodine has antiseptic properties. This solution is made by dissolving :
The solubility of ammonium chloride in water at various temperatures is given below :
| Temperature | : | 10°C | 20°C | 40°C | 60°C | 80°C |
| Solubility | : | 24 g | 37 g | 41 g | 55 g | 66 g |
What mass of ammonium chloride would be needed to make a saturated solution of ammonium chloride in fifty grams of water at 40°C ?
Name the process by which common salt is purified.
Fill in the following blanks with suitable words :
A mixture of kerosene and petrol can be separated by .....................
Explain how, impure copper sulphate can be purified by crystallisation.
There are three liquids A, B and C, all having different densities and different boiling points. Liquids A and C are organic in nature whereas liquid B is considered to be inorganic. When liquids A and B are put together in a container, they form a single layer. On the other hand, when, liquids B and C are mixed, they form two separate layers :
(a) Which process will you use to separate a mixture of A and B ?
(b) Which method will you use to separate a mixture of B and C ?
(c) Name the liquids which would behave like (i) A (ii) B and (iii) C.
A solid mixture contains four constituents P, Q, R and S. P consists of tiny grains and it is mixed with
cement for plastering the walls. Q is a white solid which is recovered on a large scale from sea water by the
process of evaporation. R is in the form of tiny particles of a material whose corrosion is called rusting. And
S is a white solid which is used in making ordinary dry cells.
- What could P, Q, R and S be ?
- How would you separate a mixture containing P, Q, R and S ?
Asmita went to buy an earthen pot. There she saw many things kept for sale.
From what substance has the potter made all the things?
The non S I and S I units of some physical quantities are given in column A and column B respectively. Match the units belonging to the same physical quantity:
| (A) | (B) | ||
| (a) | degree celsius | (i) | kilogram |
| (b) | centimetre | (ii) | pascal |
| (c) | gram per centimetre cube | (iii) | metre |
| (d) | bar | (iv) | kelvin |
| (e) | milligram | (v) | kilogram per metre cube |
Celsius scale is a scale of temperature in which zero represents the melting point of ice and 100 represents the boiling point of water.
Examples of foam are ______.
