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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
The smallest unit of matter that exists freely in nature is called ...........
The inter-molecular force is maximum in
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 ...................
What is meant by saying that metals are malleable and ductile?
Name a metal which can be easily cut with a knife.
Draw a flow-chart for the schematic representation of different types of matter.
A, B and C are all liquids. Liquid A has a comparatively low boiling point. On heating, liquid A vaporises completely without leaving behind any residue. Liquid A is being used increasingly as a fuel in motor vehicles either alone or by mixing with petrol. Liquid B has a very high boiling point. It also vaporises completely on heating, without leaving any residue. Liquid B is a conductor of electricity and used in making thermometers. Liquid C has a moderate boiling point. On heating, liquid C vaporises leaving behind a white solid D which is used in cooking vegetables. The condensation of vapours from C give a liquid E which turns anhydrous CuSO4 to blue.
(a) Which liquid could be an element ? Name this element.
(b) Which liquid could be a mixture ? Name this mixture.
(c) Which liquid could be a compound ? Name this compound.
(d) What could the solid D be ?
(e) What do you think is liquid E ?
Which of the following contains less solute at a given temperature and pressure ? Unsaturated solution or Saturated solution.
Choose one term from the following which includes the other three :
aerosol, emulsion, colloid, sol
Explain what happens when a beam of light is passed through a colloidal solution.
Explain what happens when a beam of light is passed through a colloidal solution.
Define the emulsion. Give one example.
What is meant by a solution?
Fill in the following blanks with suitable words :
The gases of air can be separated by fractional distillation of liquid air because they have different..............
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 ?
Diffentiate between absorption and adsorption.
The particles in the matter are extremely small and can be seen even with a powerful microscope.
The movement of particles in liquids is ______.
Give an example of a molecule.
