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प्रश्न
Fill in the following blanks with suitable words :
An element is made up of only one kind of ........
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उत्तर
An element is made up of only one kind of atoms.
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संबंधित प्रश्न
Intermolecular space is maximum in .......... less in ............ and the least in .........
The best evidence for the existence and movement of particles in liquids was provided by :
Name the property which allows metals to be hammered into thin sheets.
Fill in the following blanks with suitable words :
Brass is an alloy which is considered a ..............
Name a non-metal :
- which is lustrous
- which is required for combustion
- whose one of the allotrophic forms is a good conductor of electricity. Name the allotrope.
- other than carbon which shows allotropy
- which is known to form the largest number of compounds
There is a large group of materials P which can be divided into three groups Q, R and S on the basis of their properties. The substances belonging to group Q can be solids, liquids or gases. The solids belonging to group Q are usually electrical insulators. Most of the substances of group R are solids which are good conductors of electricity. The substances belonging to group S are neither insulators like Q nor good conductors like R. The properties of S are intermediate between those of Q and R.
- What could the group of materials P be ?
- Name the substances Q. Give two examples of such substances.
- Name the substances R. Write two examples of such substances.
- Name the substances S. Give two examples of such substances.
- Out of Q, R and S, which substances are malleable and ductile ?
How will you differentiate between a suspension and a colloid ?
You have been given a suspension and a solution. How could you tell the difference between them by their appearance ?
Which of the following represents the solubility of sugar in water at 20°C ?
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.
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
How would you obtain sodium chloride from a mixture of sodium chloride and sulphur without using water ?
How would you separate iodine from a mixture of iodine and common salt ?
Describe the method of separating a mixture containing common salt, sand and ammonium chloride.
Draw a labelled diagram of the fractional distillation apparatus used for separating a mixture of alcohol and water.
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 ?
Select the correct answer from A, B, C, D & E for the statement given below:
An atom or group of atoms _________ having a resultant charge.
Define the term matter.
Why wires cannot be drawn from materials such as stone or wood?
Evaporation is always accompanied by ______ in temperature.
