Question:
What is meant by saying that metals are malleable and ductile ?
Answer:
Metals are Malleable. This means that metals can be beaten into thin sheets with a hammer (without breaking). Gold and silver metals are some of the best malleable metals.
Metals are Ductile. This means that metals can be drawn (or stretched) into thin wires. All the
Is Matter Around Us Pure?
Q 1.
What is the general name of the process by which tea-leaves are separated from prepared tea ?
Q 2.
How much water should be added to 15 grams of salt to obtain 15 per cent salt solution ?
Q 3.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 4.
Name one pair of substances whose mixture can be separated by fractional distillation.
Q 5.
Name one pair of liquids which can be separated by using a separating funnel.
Q 6.
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
Q 7.
Calculate the mass of glucouse and mass of water required to make 200g of 25% solution of glucouse.
Q 8.
Define Brownian movement in colloids.
Q 9.
Name the property :
(a) which allows metals to be hammered into thin sheets.
(b)
Q 10.
Give two reasons for supposing that water is a compound and not a mixture.
Q 11.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 12.
What are non-aqueous solutions?
Q 13.
What is saturated solution? Explain with an example.
Q 14.
To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293K. Find its concentration at this temperature.
Q 15.
Name a non-metal which is a good conductor of electricity.
Q 16.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 17.
Which technique can be used to detect and identify traces of poison present in the stomach wash of a person ?
Q 18.
State the differences between compounds and mixtures.
Q 19.
Which of the following is a mixture ?Salt, Air, Water, Alum, Sugar
Q 20.
How much water should be mixed with 12 mL of alcohol so as to obtain 12 % alcohol solution ?
Q 21.
What is the concentration of a solution which contains 16 g of urea in 120 g of solution ?
Q 22.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 23.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 24.
Name the source from which nitrogen and oxygen are obtained on a large scale.
Q 25.
Name the apparatus you would use to separate oil from water.
Q 26.
What are the kinds of mixture?
Q 27.
What is meant by solute and solvent?
Q 28.
What are different ways to separate solid mixtures?
Q 29.
Who used the term 'element' first time?
Q 30.
Identify the following as mixture or compound.
(i) blood
(ii) common salt
(iii) sugar
(iv) brass
Q 31.
State whether the following statement is true or false : Milk is a pure substance.
Q 32.
What is the general name of the materials which contain at least two pure substances and show the properties of their constituents ?
Q 33.
What are pure substances ? Give two examples of pure substances.
Q 34.
How is cream separated from milk ?
Q 35.
What are different categories of pure substance?
Q 37.
What is a compound? Give an example.
Q 38.
What is an unsaturated solution?
Q 39.
Explain with an example what is a colloid?
Q 40.
What are the physical states of dispersed phase and dispersion medium of a cloud?
Q 41.
What are the properties of a colloid?
Q 42.
How are sol, solution and suspension different from each other?
Q 43.
A solution contains 40 mL of ethyl alcohol mixed with 100mL of water. What is the concentration of the solution in terms of volume by volume percentage?
Q 44.
Winnowing works on what property?
Q 45.
Name the technique to separate
(i) butter from curd
(ii) salt from sea-water
(iii) camphor from salt
Q 46.
How many elements are there which are in gaseous state at room temperature?
Q 47.
Name the elements are in liquid state at room temperature.
Q 48.
Give examples of liquids that are
(i) completely miscible
(ii) partially miscible
(iii) practically immiscible
Q 49.
What is meant by saying that metals are malleable and ductile ?
Q 50.
(a) What is a physical change ? Give two examples of physical changes.
(b) What is a chemical change ? Give two examples of chemical changes.
