Advertisements
Advertisements
प्रश्न
Which of the following materials fall in the category of a “pure substance”?
- Ice
- Milk
- Iron
- Hydrochloric Acid
- Calcium oxide
- Mercury
- Brick
- Wood
- Air
उत्तर १
- Ice
- Iron
- Hydrochloric acid
- Calcium oxide
- Mercury
उत्तर २
- Ice, iron, calcium oxide, and mercury are pure substances because they consist of only one type of matter.
- Milk, hydrochloric acid (hydrogen chloride gas dissolved in water), brick and air are not pure substances because they contain particles of more than one type of matter.
APPEARS IN
संबंधित प्रश्न
Define the following term of Matter .
Out of solids, liquids and gases, which one has :
- maximum movement of particles ?
- maximum interparticle attractions ?
- minimum spaces between particles ?
What is meant by saying that non-metals are brittle ?
Give reason why copper metal is used for making electric wires.
Define a compound. Give two points of evidence to show that sodium chloride is a compound.
Which of the following are not compounds ?
Chlorine gas, Potassium chloride, Iron powder, Iron sulphide, Aluminium foil, Iodine vapour, Graphite, Carbon monoxide, Sulphur powder, Diamond
A, B and C are all liquids. Liquid A has a comparatively low boiling point. On heating, liquid A vaporises completely without leaving behind any residue. Liquid A is being used increasingly as a fuel in motor vehicles either alone or by mixing with petrol. Liquid B has a very high boiling point. It also vaporises completely on heating, without leaving any residue. Liquid B is a conductor of electricity and used in making thermometers. Liquid C has a moderate boiling point. On heating, liquid C vaporises leaving behind a white solid D which is used in cooking vegetables. The condensation of vapours from C give a liquid E which turns anhydrous CuSO4 to blue.
(a) Which liquid could be an element ? Name this element.
(b) Which liquid could be a mixture ? Name this mixture.
(c) Which liquid could be a compound ? Name this compound.
(d) What could the solid D be ?
(e) What do you think is liquid E ?
What is the most common way of expressing the concentration of a solution ?
Choose the correct answer.
A 15% alcohol solution means :
Calculate the concentration of a solution which contains 2.5 g of salt dissolved in 50 g of water.
Name the different types of solutions. Give one example of each.
9.72 g of potassium chloride dissolves in 30 g of water at 70°C. Calculate the solubility of potassium chloride at that temperature.
Name the process which is used in milk dairies to separate cream from milk.
Fill in the following blanks with suitable words :
A mixture of kerosene and petrol can be separated by .....................
Write a method to separate a mixture of sand and potash alum.
How will you separate water from mustard oil ?
Explain how, impure copper sulphate can be purified by crystallisation.
The correct increasing order of the boiling points of liquid oxygen, liquid argon and liquid nitrogen present in liquid air is :
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 ?
Which statement is not correct for a mixture
