Short Questions Flashcards
What is pure substance?
A pure substance consists of a single type of particles.
What do you mean by mixture?
Mixtures are constituted by more than one kind of pure form of matter.
What is impure substance?
An impure substance is made of two or more elements or compounds that are not bonded together chemically.
What are the types of mixture?
There are two types of mixtures are: homogenous mixture and heterogeneous mixtures.
What do you mean by concentration of solution?
The concentration of a solution is the amount of solute present per unit volume or per unit mass of the solution.
What is distillation?
Distillation is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation.
What types of mixtures are separated from the crystallization technique?
Crystallisation technique is used to purify solid with some impurities in it.
What is saturated solution?
Solvent when no more solute can dissolve further at a given temperature is called saturated solution.
What is filtration?
Filtration is a process used to separate solids from liquids or gases using a filter medium that allows the fluid to pass through but not the solid.
What is sublimation?
Sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase.
Is whipped cream a colloid? If yes, what type is it?
Yes, it is colloid. It is air dispersed in liquid cream.
Write an example of a solution in which both solute and solvent are liquids
Ethyl alcohol (solute) and water (solvent) both are liquids forming a solution.
Write one property of suspension.
Sedimentation. The suspended particles settle to the bottom of the container on account of gravitational force.
Smoke and fog both are aerosols. In what way are they different?
The dispersed phase in fog is liquid and in smoke is solid.
Among helium and ammonia which one is element and compound?
Element- helium
Compound- ammonia
How can we separate a mixture of two miscible liquids ?
- What separation technique will you apply for separation of the following ?
(i) Ammonium chloride from sodium chloride.
(ii) Different pigments from the extract of flower petals.
How do we test purity of substances?
Name the process to separate the particles of colloid.
What is meant by fractionating column?
What are metalloids?
Suggest any one method by which we can increase the solubility of saturated solutions.
Why dry ice does not wet the surface on which it is kept?
State two reasons to justify that air is a mixture and water is compound.
Distinguish between homogeneous and heterogeneous mixture.
Classify the following mixtures as homogeneous and heterogeneous.
(i) Tincture of iodine (iv) Sugar solution
(ii) Smoke (iii) Brass
A solution of acetone contains 30 ml of acetone in 570 ml of water. Calculate the percentage concentration of the solute in the solution.
The concentration of a salt solution in terms of mass by mass percentage is 20 and the mass of the solution is 550 g. Determine the mass of solute present
in the solution.
Identify the physical and chemical changes from the following
(i) Burning of magnesium in air (ii) Electrolysis of water
(iii) Tarnishing of silver spoon (iv) Sublimation of iodine
Fine beam of light entering through a small hole in a dark room, illuminates the particles in its path. Name the process associated and Explain.
Distinguish among soda water, milk and muddy water in a tabular form under the following heads :
(i)Stability
(ii)Filterability
(iii)Type of mixture
(iv) Tyndall effect
a) 110 g of salt is present in 550g of solution. Calculate the concentration of solution.
b) 10 ml of H2SO4 is dissolved in 90 ml of H2O. Calculate the concentration of solution.
State the condition for using the method of centrifugation to separate contents of a mixture. State the principle involved in this process.
Enumerate any two differences between simple distillation and fractional distillation.
Few iron filings and a pinch of sulphur powder are taken in a china dish and mixed properly. Justify the change, giving two points as physical/chemical
change.
How can we check the purity of substance?
The purity of a substance can be checked by boiling or melting it. If it gives a sharp boiling or melting point it is a pure substance.
Write one property of suspension.
The suspended particles settle to the bottom of the container on account of gravitational force. (sedimentation)
Give one example of Tyndall effect observed in your surroundings.
When sunlight passes through the canopy of a dense forest.
While diluting a solution of salt in water, a student by mistake added acetone.What technique can be employed to get back the acetone
The technique employed to get back acetone is distillation. Since acetone is more volatile it will separate out first.
Define solubility
Solubility is the number of grams of a substance that can be dissolved in 100g of water at a specified temperature to make a saturated solution.
.a) What is solute and solvent in aerated drinks?
b) Given a solution of substance ‘A’ how will you test whether it is saturated or unsaturated with respect to ‘A’ at the given temperature.
Draw a neat labeled diagram of the apparatus used for separating acetone and water (forming a miscible mixture) from their mixture.
Two miscible liquids A and B are present in a solution. The boiling point of A is 60° C while that of B is 98° C. Suggest a method to separate the components
of mixture. Why are they separated by this process ?
Which technique, crystallization or evaporation is better to obtain salt from sea water?
.Name the technique used for separation of those solutes that dissolve in the same solvent and give any two applications of this technique.
What separation technique will you apply for the separation of the following?
a) Sodium chloride from its solution b) Tea leaves from tea
c) Different pigments from an extract of leaves d) Butter from curd
e) Fine mud particles suspended in water f) Iron pins from sand
Describe the method used for separating the components of blood. List its any two applications.
Write any three differences between a compound and a mixture.
Classify the following into physical or chemical change :
(i)burning of a candle (iv) fading of clothes
(ii)Tarnishing of silver spoon (v)mixing of iron filings and sand
(iii)Sublimation of iodine (vi) Electrolysis of water
Distinguish between elements and compounds with one example of each.
Elements are classified as metals, non-metals and metalloids. Give any one property of each. Also give one example of each
State the principle involved in the following separating techniques.
i) Chromatography ii) Distillation iii) Evaporation
How will you obtain blue dye from blue ink experimentally? How is this technique different from distillation?
Arushi’s mother always squeezes water from wet clothes in the spinner of washing machine and then uses it to clean the floor.
a) Write the principle of the technique used in the above mentioned process.
b) Write one more application of this technique.
c) What do you learn from Arushi’s mother
Why is air considered as mixture? Give an example of heterogenous mixture.
Air is considered as mixture because its composition varies.
Iodized table salt.
Define Tyndall effect
The phenomenon of scattering light by the particles due to which the path of light becomes visible.
Name two elements which exist in liquid state at room temperature.
Gallium and mercury.
What is mass per cent of a solution?
It is defined as the mass in grams of the solute present in one hundred grams of a solution.
How can you change a saturated solution to an unsaturated solution without adding any more solvent to it?
By heating the saturated solution, it becomes unsaturated.
List the points of differences between homogeneous and heterogeneous mixtures.
Homogeneous mixture
Its constituent’s particles cannot be seen easily.
There are no visible boundaries of separation in a homogeneous mixture.
Its constituents cannot be easily separated.
Examples: Alloys, solution of salt in water etc.
Heterogeneous mixture
Its constituent particles can be seen easily.
Have visible boundaries of separation between the constituents.
Its constituents can be separated by simple methods.
Examples: Mixture of sand and common salt, mixture of sand and water etc.
How are sol, solution and suspension different from each other?
Solution or true solution is homogeneous.
NO Tyndall effect.
Solute particles cannot be filtered by using a filter paper
True solution is transparent.
Examples: Sea water, alloys, solution of lemon juice in water etc.
Sol (colloidal solution) :
Sol or colloidal solution is heterogeneous.
Tyndall effect.
Cannot be separated by ordinary filter paper.
It may be transparent or translucent.
Examples: Milk of magnesia, cough syrup, mist, fog, clouds, smoke, mud etc.
Suspension :
Suspension is also heterogeneous.
Tyndall effect.
It may be transparent or translucent.
Separated easily by filter paper.(because of large particles)
Examples: Mixture of sand in water, mixture of chalk in water.
What are the two components of a colloidal solution?
Dispersed phase and dispersing medium.
Name the technique to separate
a. Camphor from salt
b. Salt from sea-water
a. Sublimation
b. Evaporation.
Give two examples each for
(i) aerosols
(ii) emulsion
Aerosol- clouds, smoke
Emulsion- milk, face cream
Which of the following will show ‘Tyndall effect’?
i. Milk
ii. Salt solution
Milk- yes
Salt solution -no
To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.
Mass of sodium chloride (solute) = 36 g
Mass of water (solvent) = 100 g
We know that, mass of solution = mass of solute + mass of solvent
= 36 g+ 100 g= 136 g
Concentration (mass percentage) of the solution
Mass of Solute/Mass of Solutionx 100
= 36g/136 g x 100 = 26.47%
