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प्रश्न
Give reason why copper metal is used for making electric wires.
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उत्तर
Copper is a good conductor of electricity. It is ductile and less expensive; therefore, it is used for making electrical wires.
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संबंधित प्रश्न
Define the term matter. What is it composed of?
Liquids have definite shape and definite volume.
Define matter.
Fill in the blank
All matter is made up of tiny particles called ______
Write true or false for each statement. Rewrite the false statement correctly.
Matter cannot exist in different states.
Explain why steel is used to make railway lines.
Which type of elements, metals or non-metals, show the property of brittleness ?
Classify the following into elements and compounds :
- H2O
- He
- Cl2
- CO
- Co
You are given two liquids, one a solution and the other a compound. How will you distinguish the solution from the compound ?
What are (i) metals (ii) non-metals, and (iii) metalloids ? Give two examples each of metals, non-metals and metalloids.
There are three substances X, Y and Z. The substance X does not have a fixed melting point or boiling point and it still shows the individual properties of its constituents. The substance Y is a pure substance which occurs in nature as such. The substance Y has a fixed melting point and boiling point but it cannot be broken down into simpler substances by any chemical means. The substance Z is also a pure substance whose properties are entirely different from those of its constituents. The substance Z can, however, be divided by electrolysis into two substances which belong to the same class of substances as Y.
- What type of substance could X be ? Name one substance like X.
- What type of substance could Y be ? Name one substance like Y.
- What type of substance could Z be ? Name one substance like Z.
- Which process involves absorption or release of an appreciable amount of energy : formation of substance X or formation of substance Z ?
- Name the three groups into which all the substances like Y are divided on the basis of their properties.
How will you differentiate between a suspension and a colloid ?
Name the different types of solutions. Give one example of each.
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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.
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Write a method to separate a mixture of sand and potash alum.
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 ?
Which among the following ______ will get attracted to by magnet?
Which of the following are homogeneous in nature?
(i) ice
(ii) wood
(iii) soil
(iv) air
