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प्रश्न
What is meant by (i) elements (ii) compounds, and (iii) mixtures ?Write down the names of two elements, two compounds and two mixtures.
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उत्तर
- Element: An element is a substance that cannot be split up into two or more simpler substances by chemical methods. It contains only one type of atoms. Examples of elements include:
- Non metals: Carbon and oxygen
- Metals: Aluminum, iron, copper, gold, mercury, and lead.
- Compound: A compound is a substance consisting of two or more elements combined chemically in a fixed proportion by mass.
Examples: Water, sodium chloride, calcium carbonate etc. - Mixture: – A mixture is a substance that is made up of two or more different kinds of particles or two or more pure substances mixed together by a physical process. Examples: Air, milk, wood, soil etc.
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संबंधित 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
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 ...................
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?
State two physical properties on the basis of which metals can be distinguished from non-metals.
Define a compound. Give two points of evidence to show that sodium chloride is a compound.
Which of the following are compounds ?
- CO
- No
- NO
- Co
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
What is a suspension ? Give two examples of suspensions.
Name the process which can be used to recover salt from an aqueous salt solution.
Name the process by which common salt is obtained from sea-water.
Which technique is used in a washing machine to squeeze out water from wet clothes while drying ?
How will you separate a mixture of iron filings, chalk powder and common salt ?
The material which is added to water during purification process at the water works so as to disinfect it is :
You are given a mixture of iodine in alcohol called tincture iodine. Which method will you use to recover both, iodine as well as alcohol, from this mixture ?
______ is not made of matter.
Which among the following is not a matter?
Compressibility of solids: ______.
Give an example of liquid in gas.
Define the term matter.
