Solutions

Question 1

solution

Answer 1

a mixture where the particles of a solute are homogeneously spread amongst the particles of a sovent

Question 2

solubility

Answer 2

given as the mass that can dissolve in 100g of water

Question 3

most solids increase in solubility with…

Answer 3

increasing temperature

Question 4

unsaturated solution

Answer 4

contains less solute than it is able to dissolve

Question 5

saturated solution

Answer 5

contains as much solute as it can normally dissolve

Question 6

supersaturated solution

Answer 6

contains more solute that it can normally dissolve

Question 7

strong electrolytes

Answer 7

when these dissolve in water they are entirely present (or at least mostly) as independent ions

• ionic compounds
• covalent molecular (if strong acid)

Question 8

weak electrolytes

Answer 8

when these dissolve in water they are partly present as independent mobile ions (but mostly as molecules)
-covalent molecular (if weak acid or base)

Question 9

non-electrolytes

Answer 9

when these dissolve in water they do not produce ions; they are entirely present as molecules

• most covalent molecular substances
• ALWAYS PRODUCE NON-CONDUCTING SOLUTIONS

Question 10

dissociation

Answer 10

when ionic electrolyte dissolves, ions present are released into water forming a solution of independent mobile ions

is a general process in which molecules (or ionic compounds such as salts, or complexes) separate or split into smaller particles such as atoms, ions or radicals, usually in a reversible manner.

Question 11

ionisation

Answer 11

molecules of the electrolyte react with water to form ions not originally present within the substance

any process by which electrically neutral atoms or molecules are converted to electrically charged atoms or molecules (ions)

Question 12

electrical conductivity of a solution

Answer 12

depends on the ability of positive ions to move freely towards the negative electrode while negative ions move freely towards the positive electrode
- thus greater concentration of ions the greater its ability to conduct

Question 13

precipitation reaction

Answer 13

occurs when an insoluble solid forms with a previously clear solution

Question 14

role of water in the human body

Answer 14

solvent for metabolic processes
transporting nutrients
essential for excretion of cellular waste
evaporation of water helps with temperature regulation

Question 15

potable water

Answer 15

water safe enough to drink and cook with
should be:
clear
colourless
odourless
contain no pathogens or toxic substances
pleasant in taste

Question 16

mix of water in WA

Answer 16

40% ground water
27% water distillation
33% surface water

Question 17

two approaches to making salt water potable

Answer 17

distillation

reverse osmosis

Question 18

distillation

Answer 18

water is evaporated form the salts in sea water and then condensed (in several stages called multi-stage flash distillation) to produce distilled water

desalination by distillation plants involve evaporation of water followed by its condensation to produce distilled water. requires a large amount of energy; extra energy needed for evaporation is a result of strong intermolecular forces in water.

Question 19

reverse osmosis

Answer 19

commercial reverse osmosis (RO) units use high pressure to force water through semi permeable membrane in the opposite direction to which water would naturally flow

pressure is applied to salty water forcing water to pass through the SPM in an opposite direction to what happens naturally in osmosis. This in RO water is forced to diffuse through an SPM from a high salt concentration (e.g. sea water) to a very low salt (zero salt) concentration called permeate (fresh water).