Redox and acids

Question 1

Define oxidation

Answer 1

• Loss of electrons
• Increase in oxidation numbers

Question 2

Define reduction

Answer 2

• Gain of electrons
• Decrease in oxidation numbers

Question 3

Define redox reactions

Answer 3

Reactions in which both reduction and oxidation takes place simultaneously

Question 4

Define an oxidising agent

Answer 4

Is a reagent which oxides another species

Question 5

Define a reducing agent

Answer 5

Is a reagent which reduces another species

Question 6

What is the oxidation number rule for any element on its own

Answer 6

Is 0
e.g Na = 0

Question 7

What is the oxidation number rule for a simple ion

Answer 7

Is the charge on the ion
e.g Na+ = +1
o2- = -2

Question 8

What is the oxidation number rule for a group 1,2 and 3 element in a compound

Answer 8

The charge is equal to group number
e.g KCl = +1 (K)

Question 9

What is the oxidation number rule for a compound

Answer 9

The sum of the oxidation numbers of all atoms and ions in a compound
e.g Na2O = (2x1) + -2 = 0

Question 10

What is the oxidation number rule for group 7 elements in a compound

Answer 10

Usually -1 ( but there are exceptions)
e.g Cl= -1

Question 11

What is the oxidation number rule for hydrogen bonded to a non-metal

Answer 11

Is +1
e.g HCl = +1 (H)

Question 12

What is the oxidation number rule for hydrogen bonded to a metal

Answer 12

Is -1
e.g LiAlH4 = -1(H)

Question 13

What is the oxidation number rule for an oxygen in a compound

Answer 13

Usually -2
e.g Na2O = -2(O)

Question 14

What is the oxidation number rule for an oxygen in a peroxide

Answer 14

Is -1
e.g H2O2 = -1 (O)

Question 15

What is the oxidation number rule for a complex ion

Answer 15

The sum of the oxidation number of all atoms and ions in an ion is equal to the charge
e.g CO3 -2
+4 + (3x2) = -2

Question 16

Define acid

Answer 16

Proton donors in solution

Question 17

Define strong acid

Answer 17

Fully dissociates its H+ ions in aqueous solution

Question 18

Define weak acid

Answer 18

Partially dissociates its H+ ions in aqueous solution

Question 19

Define base

Answer 19

A proton acceptor

Question 20

Define alkali

Answer 20

Is a type of base that dissolves in water forming OH- ions

Question 21

Define salt

Answer 21

A compound produced when a H+ ion from an acid is replaced by a metal or another positive ion such as ammonium ion

Question 22

What are the products and observations when an acid reacts with a base

Answer 22

Products= salt + water
Observations= Solid dissolves

Question 23

What are the products and observations when an acid reacts with an alkali

Answer 23

Products= salt + water
Observations= no visible changes ( unless indicator is used)

Question 24

What are the products and observations when an acid reacts with a carbonate

Answer 24

Products= salt + water + CO2
Observations= Solid dissolves and bubbles of gas

Question 25

What are the products and observations when an acid reacts with a metal

Answer 25

Products= salt + H2
Observations= Solid dissolves and bubbles of gas

Question 26

What salt is made when using hydrochloric acid

Answer 26

Makes a chloride salt
e.g MgCl2

Question 27

What salt is made when using sulphuric acid

Answer 27

Makes a sulfate salt
e.g FeSO4

Question 28

What salt is made when using ethanoic acid ( weak acid)

Answer 28

Ethanoate salt
e.g CH3COOK

Question 29

What salt is made when using nitric acid

Answer 29

Makes a nitrate salt