Elements, Compounds and Mixtures Test - 1

The volume of the solute does not affect its solubility.

The correct answer is C.

Why alternatives A and B are wrong:

Solubility depends upon the nature of the solute and the solvent. Polar solutes dissolve in polar solvents and non-polar solutes dissolve in non-polar solvents.

Why alternative D is wrong:

An increase in the temperature of the solution increases the solubility of a solid solute.

A solution is a homogeneous mixture of two or more substances. Salt forms a homogeneous mixture with water, which means that particles of salt are evenly distributed in the mixture. Hence, salt will form a solution with water.

An element cannot be further broken down into other substances.

The correct answer is A.

Why alternative B is wrong:

A compound is a combination of two or more different elements in a fixed ratio. It can be broken down into simpler substances. Therefore this alternative is incorrect.

Why alternative C is wrong:

Mixture is a combination or mixing of elements and compounds. It can be broken down into simpler compounds. Therefore alternative C is incorrect.

Why alternative D is wrong:

Colloid is also a mixture. It can be broken down into simpler substances. Therefore alternative D is incorrect.

Evaporation is used to separate the mixture of solids and liquids. The liquid component of the mixture evaporates, leaving behind the solid residue. Sea water is collected in shallow fields and the heat of the sun makes the water evaporate, leaving behind the salt in heaps.

The correct answer is B.

Why alternative A is wrong:

Filtration is the process of separating un-dissolved particles from a liquid by letting the liquid pass through the fine holes of a filter.

Why alternative C is wrong:

Sublimation is the process of separating solid mixtures. If a mixture contains a solid which directly changes into vapour, either at room temperature or upon heating, then the mixture can be separated through the process of sublimation.

Why alternative D is wrong:

Precipitation is the method used to make a compound appear in its solid state in a solution. The precipitate of the compound can then be used for other purposes.

Brass is an alloy of copper and zinc. These two metals cannot be separated by physical methods as they exist in a single phase. Hence, brass is an example of a homogeneous mixture of metals.

The correct answer is D.

Why alternative A is wrong:

The mixture of iron and calcium is a heterogeneous mixture as iron and calcium can be separated by the application of a magnetic force.

Why alternative B is wrong:

The mixture of iron and copper is a heterogeneous mixture as iron and copper can be separated by the application of a magnetic force.

Why alternative C is wrong:

Iron, existing in its pure form, is an element, and not a mixture.

Two or more atoms of different elements joined together to form a chemical

compound.

A mixture of two miscible liquids having the difference in their boiling points less than 25 K can be separated by the process of fractional distillation. The liquid with the lower boiling point vapourizes first, condenses, and can be collected.

Supersaturated solutions form crystals easily.

The correct answer is B.

Why alternative A is wrong:

Slightly saturated solution will not yield significant amount of crystals. It will only form crystalline powder.

Why alternative C is wrong:

There is no such solution which can be termed as vaporized solution.

Why alternative D is wrong:

Frozen solution is a solid itself. It will not give any further crystals.

Distillation is used to separate a mixture of liquids. This method works when the liquids in the mixture have different boiling points. Since water and acetic acid are completely miscible and together form vinegar, distillation will be the best method to separate them.