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प्रश्न
Name two solid, two liquid and two gaseous elements at the room temperature.
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उत्तर
Aluminium and copper are two elements that are solid at room temperature. Both bromine and mercury are liquid at room temperature. Nitrogen and hydrogen are two elements that are gaseous at room temperature.
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संबंधित प्रश्न
Classify the following into elements, compounds and mixtures:
- Sodium
- Soil
- Sugar solution
- Silver
- Calcium carbonate
- Tin
- Silicon
- Coal
- Air
- Soap
- Methane
- Carbon dioxide
- Blood
The best evidence for the existence and movement of particles in liquids was provided by :
When extremely small particles X derived from the anther of a flower were suspended in a liquid Y and observed through a microscope, it was found that the particles X were moving throughout the liquid Y in a very zig-zag way. It was also observed that warmer the liquid Y, faster the particles X moved on its surface.
- What could particles X be ?
- What do you think liquid Y is ?
- What is the zig-zag movement of X known as ?
- What is causing the zig-zag movement of particles X ?
- Name the scientist who discovered this phenomenon.
- What does this experiment tell us about the nature of liquid Y?
Name the property which allows metals to be hammered into thin sheets.
Explain why, hydrogen and oxygen are considered elements whereas water is not considered an element.
What are the three groups into which all the elements can be divided ? Name two elements belonging to each group.
Name a metal which is yellow in colour.
9.72 g of potassium chloride dissolves in 30 g of water at 70°C. Calculate the solubility of potassium chloride at that temperature.
What difference in the property of two miscible liquids enables their separation by fractional distillation ?
State whether the following statement are true or false :
Alcohol can be separated from a mixture of alcohol and water by a separating funnel.
Write a method to separate a mixture of sand and potash alum.
Explain how, impure copper sulphate can be purified by crystallisation.
How is water purified on a large scale at water works ? Explain with the help of a labelled diagram. Name the substance which is added to kill germs in the drinking water supply ?
Which of the following mixture cannot be separated by using water as the solvent ?
Which one of the following scrap metal cannot be separated by magnetic separation ?
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 ?
The property which allows the metals to be hammered into their sheets is ______.
______ is a smallest particle.
Which statement is not correct for a mixture
Evaporation does form bubbles.
