List the points of differences between homogeneous and heterogeneous mixtures.
Mixtures are formed when two or more pure substances are mined together, for example : salt , solution ,air etc.
Types of mixture :
i). Homogenous mixture ii). Heterogenous mixture
i). Homogeneous mixture :
A homogenous mixture has a uniform composition throughout its mass.
The constituents of a homogeneous mixture cannot be seen easily.
Homogeneous mixture has no visible boundaries of separation between its constituents. E.g : salt solution.
ii). Heterogeneous mixture :
A heterogeneous, minture does not have a uniform composition throughout its mass.
The constituents of heterogeneous mixture can usually be seen easily.
Heterogeneous mixture has visible boundaries of respiration between the various constituents. e.g.: oil water mixture.
How are sol, solution and suspension different from each other?
Name the technique to separate
(i) butter from curd,
(ii) salt from sea-water,
(iii) camphor from salt.
Differentiate between homogeneous and heterogeneous mixtures with examples.
Identify the solutions among the following mixtures.
(a) Soil
(b) Sea water
(c) Air
(d) Coal
(e) Soda water.
Explain the following giving examples.
(a) saturated solution
(b) pure substance
(c) colloid
(d) suspension
Write the steps you would use for making tea. Use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.
Classify the following into elements, compounds and mixtures.
(a) Sodium
(b) Soil
(c) Sugar solution
(d) Silver
(e) Calcium carbonate
(f) Tin
(g) Silicon
(h) Coal
(i) Air
(j) Soap
(k) Methane
(l) Carbon dioxide
(m) Blood
Which of the following will show “Tyndall effect”?
(a) Salt solution
(b) Milk
(c) Copper sulphate solution
(d) Starch solution.
Which of the following materials fall in the category of a “pure substance”?
(a) Ice
(b) Milk
(c) Iron
(d) Hydrochloric acid
(e) Calcium oxide
(f) Mercury
(g) Brick
(h) Wood
(i) Air.
Which separation techniques will you apply for the separation of the following?
(a) Sodium chloride from its solution in water.
(b) Ammonium chloride from a mixture containing sodium chloride and ammonium chloride.
(c) Small pieces of metal in the engine oil of a car.
(d) Different pigments from an extract of flower petals.
(e) Butter from curd.
(f) Oil from water.
(g) Tea leaves from tea.
(h) Iron pins from sand.
(i) Wheat grains from husk.
(j) Fine mud particles suspended in water.
Which of the following has more inertia: (a) a rubber ball and a stone of the same size? (b) a bicycle and a train? (c) a five-rupees coin and a one-rupee coin?
State the universal law of gravitation.
Which of the following are matter?
Chair, air, love, smell, hate, almonds, thought, cold, cold-drink, smell of perfume.
A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (Fig. 11.3). Let us take it that the force acts on the object through the displacement. What is the work done in this case?
How does the sound produced by a vibrating object in a medium reach your ear?
In a reaction, 5.3 g of sodium carbonate reacted with 6 g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium observations are in agreement with the law of conservation of mass.
sodium carbonate + ethanoic acid → sodium ethanoate + carbon dioxide + water
What are canal rays?
State any two conditions essential for good health.
How is our atmosphere different from the atmospheres on Venus and Mars?
Who discovered cells, and how?
What are the limitations of Rutherford’s model of the atom?
If an atom contains one electron and one proton, will it carry any charge or not?
If Z = 3, what would be the valency of the element? Also, name the element.
If action is always equal to the reaction, explain how a horse can pull a cart.
During an experiment, a signal from a spaceship reached the ground station in five minutes. What was the distance of the spaceship from the ground station? The signal travels at the speed of light, that is, 3 × 108 m s-1.
How do substances like CO2 and water move in and out of the cell? Discuss.
What type of clothes should we wear in summer?
Soni says that the acceleration in an object could be zero even when several forces are acting on it. Do you agree with her? Why?
What is osmosis?
Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?