Advertisements
Advertisements
प्रश्न
Define the following term of Atom .
उत्तर
Atom — An atom is the smallest part of an element that takes place in a chemical reaction.
APPEARS IN
संबंधित प्रश्न
Name the terms for the change of vapour into a liquid.
Define matter. Give four examples of matter.
Name a non-metal which is a good conductor of electricity.
What is meant by saying that metals are malleable and ductile ?
Name a metal which can be easily cut with a knife.
Which one of the following is not a metalloid ?
What is the name of the clear liquid formed when a solid dissolves in a liquid ?
You have been given a suspension and a solution. How could you tell the difference between them by their appearance ?
What is meant by a solution ? Give two examples of solutions.
Which one of the following is not a chemical change ?
When the solid A is added to water, it dissolves with the evolution of a lot of heat and making little explosions to form two products B and C. The properties of products B and C are entirely different from those of solid A as well as water. Moreover, products B and C cannot be reconverted into solid A and water. When another solid D is added to water, it dissolves with the absorption of a little heat to form a product E which cools down. The product E shows the properties of both, solid D as well as water. Moreover, product E can be converted into solid D and water.
(a) What type of change occurs when solid A is dissolved in water ? Why ?
(b) What type of change occurs when solid D is dissolved in water ? Why ?
(c) Name a metal which you think could behave like solid A. Also name the products B and C.
(d) Name the solid D if it is the one which is used in making ordinary dry cells.
(e) Name the process by which D can be recovered from E.
A carpenter wants to separate iron nails from saw-dust. Which method of separation should he choose ?
Name the process which is used in milk dairies to separate cream from milk.
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 ?
Differentiate between the-two characteristics of matter – ‘mass’ & ‘weight’.
The property which allows the metals to be hammered into their sheets is ______.
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
______ is so hard that it can scratch glass.
Intermolecular space is maximum in ______.
