Water and Solutions

Question 1

Define Latent Heat of Fusion

Answer 1

The energy required to convert one mole of a substance from a solid to a liquid at its melting point

Question 2

Define Latent Heat of Vaporisation

Answer 2

The energy required to convert one mole of a substance from a liquid to a gas at its boiling point

Question 3

Define Specific Heat Capacity

Answer 3

The energy required to raise the temperature of 1g of a substance by 1 degree Celsius

Question 4

Why does water have a high latent heat?

Answer 4

Strong hydrogen bonds between water molecules absorb large amounts of heat energy and require lots to be broken.

Question 5

Define Density

Answer 5

A measure of the mass of a substance per unit volume (eg g/L)

Question 6

Outline properties of water

Answer 6

• Universal solvent
• Less dense as a solid
• Polar molecule
• High latent heat and SHC

Question 7

Define Solubility

Answer 7

The degree to which a given solute will dissolve in a given solvent. Often expressed quantitatively with the units ‘g/100g solvent’

Question 8

Ionisation

Answer 8

A reaction between a molecule and water, resulting in the formation of two dissolved ions

Question 9

Ion-dipole force

Answer 9

An attractive force between an ion and the oppositely charged pole of a polar molecule (such as water)

Question 10

solute

Answer 10

A Substance being dissolved

Question 11

Solvent

Answer 11

Liquid that dissolves a substance

Question 12

Solution

Answer 12

Solvent and solute mixture

Question 13

Solubility Curve

Answer 13

A graphical depiction of how the solute concentration required to form a saturated solution changes across a range of temperatures

Question 14

Saturated Solution

Answer 14

A solution in which the maximum amount of solute is dissolved, at that temperature

Question 15

Unsaturated Solution

Answer 15

A solution in which less than the maximum amount of solute is dissolved, at that temperature

Question 16

Supersaturated Solution

Answer 16

A solution in which more than the maximum amount of solute is dissolved, at that temperature. This is an unstable situation which can arise when a saturated solution cools, and is likely to result in crystallisation of some of the solute

Question 17

What is solution concentration?

Answer 17

Grams of solute dissolved per litre of solvent

Question 18

What is molarity

Answer 18

Moles of solute dissolved per litre of solvent

Question 19

Dilution

Answer 19

The addition of solvent, decreasing the concentration of solute in the solution

Question 20

Dilution equation

Answer 20

C1V1 = C2V2

Question 21

Strong Acid

Answer 21

Donate protons easily, Completely, ionise in solution

Question 22

Weak Acid

Answer 22

Does not donate protons easily,
Partially ionise in solution

Question 23

Formula to Calculate pH

Answer 23

pH = – log [H+]

Question 24

Calculation to find [H+]

Answer 24

[H+] = 10-pH
Units are molL-1

Question 25

pH scale range for acids and pH scale range for bases

Answer 25

0-6 & 8-14

Question 26

Conjugate Acid

Answer 26

A conjugate acid is the same as the starting base plus H+.

Question 27

Conjugate Base

Answer 27

A conjugate base is the same as the starting acid minus H+.

Question 28

Strong acids and how many protons they can donate.

Answer 28

Hydrochloric acid (HCl -1) Nitric acid (HNO3 - 1) Sulfuric acid (H2SO4 - 2) Hydrobromic acid (HBr - 1)

Question 29

Weak acids and how many protons they can donate.

Answer 29

Methanoic acid (HCOOH-1) Ethanoic acid (CH3COOH - 1) Hydrofluoric acid (HF -1) Hydrocyanic acid (HCN - 1)

Question 30

How to test for Hydrogen gas?

Answer 30

Squeaky pop test. Put lit splint into test tube and a pop sound will occur.

Question 31

How to test for Carbon Dioxide gas?

Answer 31

Bubble the gas formed from a reaction into limewater. Turns colourless to cloudy.