Is Matter Around Us Pure(9th Grade > Chemistry ) Questions and Answers
Explanation:-
Answer: Option C. -> sublimation:
C
Sublimationseparates a mixture of solids in which one solid undergoes sublimation. In other words, it changes directly to vapour on heating, without going through the liquid state.
Iodine is a solid that sublimes. When a mixture of iodine and sand is heated in a beaker, the iodine changes from solid to
vapour directly.
These vapours of iodinecan be obtained by cooling. They will change back to solid directly.
Explanation:-
Answer: Option C. -> Saturated solution:
C
In a solution, the solute is uniformly dissolved in the solvent. But there is a limit to how much solute can be dissolved and it depends on the temperature.
At any given temperature, only a certain amount of solute can be dissolved. When that point is reached, the solution is said to be saturated and we call it a saturated solution.
Explanation:-
Answer: Option A. -> Top layer - kerosene oil Bottom layer - water:
A
Kerosene oil and water form a mixture of immiscible liquids. When left undistubed, depending upon the densities of the liquid they form separate layers. The liquid that has a lower density forms the top layer and the liquid that has a higher density forms the bottom layer.
In this case, kerosene has density of 820 kg/m3 and water has a density of 1000 kg/m3. So, kerosene forms the top layer and water forms the bottom layer.
Explanation:-
Answer: Option A. -> 9.09%:
A
Mass percentage is used to measure the concentration of a solution. A solution contains solute and solvent.
Mass percentage of a solution =Mass of the soluteMass of the solution×100
Given, mass of solute = 10g
mass of solvent = 100 g
The total amount of solution = 10 + 100 = 110g
Mass percentage of a solution = 10110×100=9.09%
Explanation:-
Answer: Option C. -> Sedimentation:
C
Sedimentationis the tendency for the particles in a suspension to settle down. It is a physicalwater treatmentprocess used to remove suspended solids fromwater naturally.
Explanation:-
Answer: Option A. -> True:
A
Air is a mixture and not a compound because:
1)Air does not have a fixed composition.
2)The components of air can be separated by a physical method such as fractional distillation of liquid air.
3)We can prepare air artificially by mixing the various components of air in the same proportions in which they occur at a place.
Explanation:-
Answer: Option C. -> Distillation:
C
Miscible liquidsare thoseliquidswhich completely mix with each other and form a uniform mixture. Distillation is used for separating two miscible liquids that have a considerable difference in their boiling points.
When the mixture is heated, the liquid with a lower boiling point vaporises first and the vapours can becollected. The vapours are then condensed to get the liquid back in a separate flask. The other liquid doesn't vaporise at this temperature as it has a higher boiling point and stays liquid. So, the liquids are now separated.
Explanation:-
Answer: Option C. -> magnetic separation:
C
Magnetic separation is a methodused if one of the components of the mixture is magnetic in nature .This method is used as one of the componentgets attracted towards the magnet. In the given case, iron filings get attracted to a magnet while silverfilings wont and hence, can be separated by magnetic separation.
Explanation:-
Answer: Option A. -> They always have two phases.:
A
Acolloidis a heterogeneous mixture in which the particles of the dispersed phase are distributed non-uniformly in the dispersion medium.
A colloidal solution is always made up of two phases- dispersion medium and dispersed phase. The two phases of a colloid can be a solid, a liquid or a gas. However, its constituent particles are very small in size. Hence, it cannot be separated by filtration.
Examples of colloids are blood, paint, etc.
Explanation:-
Answer: Option C. -> Glucose in water:
C
A mixture is a combination of two or more substances in which each substance retains its individual chemical properties.
A homogeneous mixture is a solid, liquid, or gaseous mixture that has the same proportions of its components throughout any given sample. Examples- glucose in water, acetone and water, alloys of metals, sugar and water, etc.
Conversely, a heterogeneous mixture has components whose proportions vary throughout the sample. Examples- sugar and oil, soap lather, sugar and salt.