Topic 4-C5+C6

Question 1

What is the pH scale

Answer 1

The pH scale is the scale used or measure how acidic or alkaline a substance is

Question 2

What are the numbers for acid and alkali on the pH scale+colours

Answer 2

0-6–>acid–>red
7–> neutral (water)–>green
8-14–>alkali–>purple

Question 3

What is acidity and alkalinity and why is water neutral

Answer 3

Acidity is the concentration of H+ ions
Alkalinity is the concentration of OH- ions
So when the two are balanced you have H2O which is water

Question 4

What is a base

Answer 4

A base is a substance with a pH greater than 7-alkalis are bases

Question 5

Metal oxides and metal hydroxides are examples of what

Answer 5

Bases

Question 6

What is the order of the reactivity series-most reactive to least (0.5 marks per element)

Answer 6

Most
Potassium-K
Sodium-Na
Lithium-Li
Calcium-Ca
Magnesium-Mg
Carbon-C
Zinc-Zn
Iron-Fe
Hydrogen-H
Copper-Cu
Least

Question 7

What is a redox reaction

Answer 7

A reaction where electrons are transferred

Question 8

What does OIL RIG stand for

Answer 8

Oxidation Is Loss, Reduction Is Gain (of electrons)

Question 9

What is an electrolysis cell made up of

Answer 9

Positive and negative electrodes (cathode and anode)
A power supply to the electrodes
An electrolyte-a molten or dissolved ionic compound