Solvents and Solutes

Question 1

Regarding solvents, solutes and solutions (true or false):

A solution is a heterogeneous mixture of two or more substances

Answer 1

False. A solution is a homogenous mixture of two or more substances.

Question 2

Regarding solvents, solutes and solutions (true or false):

Alloys are a type of solution

Answer 2

True. Though most solutions involve liquids, alloys do classify as a kind of solution.

Question 3

Regarding solvents, solutes and solutions (true or false):

Entonox is a solution

Answer 3

False. Gases mixed together are just mixtures, although gases can dissolve in liquid.

Question 4

Regarding solvents, solutes and solutions (true or false):

Warmer water dissolves more salt than cooler water

Answer 4

True

Question 5

Regarding solvents, solutes and solutions (true or false):

Warmer water dissolves more gas than cooler water

Answer 5

False. The bubbles seen in IV fluids that have been warmed show the dissolved gases coming out of solution because of the rise in temperature.

Question 6

Regarding mixtures, colloids, suspensions and emulsions (true or false):

All colloids are mixtures, but not all mixtures are colloids

Answer 6

True. The term ‘mixture’ covers colloids, as well as emulsions and suspensions.

Question 7

Regarding mixtures, colloids, suspensions and emulsions (true or false):

Where two immiscible liquids do not remain in their desired emulsified state, the only solution is to input energy and agitate the mix

Answer 7

False. A surfactant emulsifier may in some cases be added to the mix to keep the emulsion stable.

Question 8

Regarding mixtures, colloids, suspensions and emulsions (true or false):

Propofol for injection is a solution of propofol in water

Answer 8

False. Propofol is an emulsion of lipid-soluble propofol in a watery base.

Question 9

Regarding mixtures, colloids, suspensions and emulsions (true or false):

Medical colloids are effective because the large molecular weight of the substances in them increases the oncotic pressure in the patient’s blood

Answer 9

True. The increased oncotic pressure can help prevent cerebral and pulmonary oedema.

Question 10

Regarding mixtures, colloids, suspensions and emulsions (true or false):

An emulsion is a type of colloid

Answer 10

True. An emulsion is a liquid-in-liquid colloid.

Question 11

Regarding water as a solvent (true or false):

The water molecule is polar in nature

Answer 11

True. The negatively charged oxygen atom and the positively charged hydrogen atoms give it its polarity.

Question 12

Regarding water as a solvent (true or false):

Water acts as a good solvent for polar and non-polar substances

Answer 12

False. Like dissolves like. Thus, water dissolves polar substances well.

Question 13

Regarding water as a solvent (true or false):

The vapour pressure of water increases as a solute with a higher mole fraction is dissolved into it

Answer 13

False. The vapour pressure of water falls if a solute with a higher mole fraction is added to it.

Question 14

Regarding water as a solvent (true or false):

The boiling point of water rises as a solute with a higher mole fraction is added to it

Answer 14

True. Consistent with answer C, the boiling point of water rises as solvents are added.

Question 15

Regarding water as a solvent (true or false):

The solvent in lignocaine is water

Answer 15

True

Question 16

Regarding solubility (true or false):

Solubility is increased if pressure is increased

Answer 16

True. Pressure increases solubility, especially when gases are dissolved in liquid.

Question 17

Regarding solubility (true or false):

When gases dissolve in liquids, solubility increases if the temperature of the solvent increases

Answer 17

False. Where gases dissolve in liquids, solubility falls as temperature rises.

Question 18

Regarding solubility (true or false):

When liquids dissolve in liquids, solubility increases if the temperature of the solvent increases

Answer 18

True. Where liquids, or solids, dissolve in liquids, solubility increases with temperature.

Question 19

Regarding solubility (true or false):

Solubility is enhanced by the action of surfactants

Answer 19

False. Surfactants render emulsions stable by coating the particulate matter suspended within them.

Question 20

Regarding solubility (true or false):

Solubility is affected by intermolecular forces

Answer 20

True. Intermolecular forces cause solutes to disperse evenly throughout a solvent.