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.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 3.
Name one pair of liquids which can be separated by using a separating funnel.
Q 4.
Which of the following is a mixture ?Salt, Air, Water, Alum, Sugar
Q 5.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 6.
What is saturated solution? Explain with an example.
Q 7.
Calculate the mass of glucouse and mass of water required to make 200g of 25% solution of glucouse.
Q 8.
How much water should be added to 15 grams of salt to obtain 15 per cent salt solution ?
Q 9.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 10.
What are non-aqueous solutions?
Q 11.
Define Brownian movement in colloids.
Q 12.
What is the concentration of a solution which contains 16 g of urea in 120 g of solution ?
Q 13.
Name the property :
(a) which allows metals to be hammered into thin sheets.
(b)
Q 14.
Give two reasons for supposing that water is a compound and not a mixture.
Q 15.
What is meant by solute and solvent?
Q 16.
What are the physical states of dispersed phase and dispersion medium of a fog?
Q 17.
What is meant by saying that metals are malleable and ductile ?
Q 18.
What are pure substances ? Give two examples of pure substances.
Q 19.
Name the technique to separate
(i) butter from curd
(ii) salt from sea-water
(iii) camphor from salt
Q 20.
What is an emulsion? Give examples
Q 21.
Name a non-metal which is a good conductor of electricity.
Q 22.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 23.
Name the source from which nitrogen and oxygen are obtained on a large scale.
Q 24.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 25.
Name the apparatus you would use to separate oil from water.
Q 26.
What is a solution? What are the properties of a solution?
Q 27.
What is an unsaturated solution?
Q 28.
Name one pair of substances whose mixture can be separated by fractional distillation.
Q 29.
State the differences between compounds and mixtures.
Q 30.
What principle is applied in centrifugation? Give examples where this method is applied to separate mixtures.
Q 31.
Which of the following will show Tyndall effect ? Why ?
(a) Salt solution
(b) Starch solution
(c)Milk
Q 32.
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 33.
What are different ways to separate solid mixtures?
Q 34.
What are the reasons for separating the constituents of a mixture?
Q 35.
(a) What is meant by (i) elements (ii) compounds, and (iii) mixtures ? Write down the names of two elements,two compounds and two mixtures.
(b) Classify the following into elements,
compounds and mixtures :
Marble,
Air,
Gold,
Brass,
Sand,
Diamond,
Graphite,
Petroleum,
Common salt,
Sea-water,
Chalk
Q 36.
Choose one term from the following which includes the other three :
aerosol,
emulsion,
colloid,
sol
Q 37.
Name any two solid substances whose mixture can be separated by sublimation.
Q 38.
What are the kinds of mixture?
Q 39.
What are the characteristics of mixture?
Q 40.
List the points of differences between homogeneous and heterogeneous mixtures.
Q 41.
What are aqueous solutions?
Q 42.
What are the advantages of preparing solutions?
Q 43.
What is supersaturated solution?
Q 44.
What are the various methods to express concentration of a solution?
Q 45.
How crystallization is better than evaporation?
Q 46.
What is Chromatography?
Q 47.
Name the following :
(a) a lustrous liquid metal.
(b) a liquid non-metal
(c) a metal which can be cut with a knife
(d) a non-metal which is good conductor of electricity.
(e) an element which melts when kept on the palm.
(f) the best conductor of heat.
Q 48.
How many elements are there which are in gaseous state at room temperature?
Q 49.
Identify the following as mixture or compound.
(i) blood
(ii) common salt
(iii) sugar
(iv) brass
Q 50.
Give examples of liquids that are
(i) completely miscible
(ii) partially miscible
(iii) practically immiscible
