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प्रश्न
When a crystal of potassium permanganate is placed in a beaker, its purple colour spreads throughout the water. What does this observation tell us about the nature of potassium permanganate and water?
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उत्तर
The particles of potassium permanganate and water mix on their own without any stirring. Two conclusions can be drawn from this phenomenon. These are:
- Potassium permanganate and water are made up of very tiny particles.
- Water particles have large spaces between them which are occupied by the tiny potassium permanganate particles.
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संबंधित प्रश्न
Fill in the following blank with suitable words :
The best evidence that the particles of matter are constantly moving comes from the studies of ................. and ...................
The best evidence for the existence and movement of particles in liquids was provided by :
Which of the following is a mixture ?
Salt, Air, Water, Alum, Sugar
Name a metal which is soft and a non-metal which is hard.
The three important metalloids are.............................. and ..........................
Classify the following as elements or compounds :
Iron, Iron sulphide, Sulphur, Chalk, Washing soda, Sodium, Carbon, Urea
Give reason why copper metal is used for making electric wires.
Which of the following statements are true for pure substances ?
- pure substances contain only one kind of particles
- pure substances may be compounds or mixtures
- pure substances have the same composition throughout
- pure substances can be exemplified by all elements other than nickel
Out of a colloid, solution and a suspension :
which one has the smallest particles ?
What is the difference between solutions and colloids ?
Define the emulsion. Give one example.
Which of the following is not an emulsion ?
A carpenter wants to separate iron nails from saw-dust. Which method of separation should he choose ?
How would you obtain sodium chloride from a mixture of sodium chloride and sulphur without using water ?
Explain how, impure copper sulphate can be purified by crystallisation.
The liquid air has three components X, Y and Z whose boiling points are : –186°C, –183°C and –196°C,
respectively. When liquid air is fed into a tall fractional distillation column from near its bottom and warmed
up slowly :
(a) Which component will be collected from near the bottom of the fraction distillation column ? Why ?
(b) Which component will be collected from the top part of the fractional distillation column ? Why ?
(c) Which component will be collected from the middle part of the fractional distillation column ? Why ?
(d) What could the component X, Y and Z be ?
Tincture of iodine is a mixture of two materials X and Y. The material Y has a property that its solid form can be converted directly into vapours on heating by a process called Z.
- What could X be ?
- What could Y be ?
- Name the process Z.
- Which process would you use to recover both the components X and Y from tincture of iodine ?
- Which process can be used to recover only component Y from tincture of iodine ?
Which of the following statements are true for pure substances?
(i) Pure substances contain only one kind of particles
(ii) Pure substances may be compounds or mixtures
(iii) Pure substances have the same composition throughout
(iv) Pure substances can be exemplified by all elements other than nickel
Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.
Name a non-metal which exists as a liquid at room temperature.
Define the term matter.
