ES2: Redox

Question 1

Define “oxidation”

Answer 1

The loss of electrons or the gain of oxygen

Question 2

Is hydrogen removed or gained in oxidation?

Answer 2

Removed

Question 3

Give the general equation for oxidation.

Answer 3

K===> K+ + e-

Question 4

Is there an increase or a decrease in oxidation numbers during oxidation?

Answer 4

Increase

Question 5

Define “reduction”

Answer 5

The gain of electrons or the loss of oxygen

Question 6

Is hydrogen removed or gained in reduction?

Answer 6

Gained

Question 7

Give the general equation for reduction.

Answer 7

K+ + e- ===> K

Question 8

Is there an increase or a decrease in oxidation numbers during oxidation?

Answer 8

Decrease

Question 9

What is a redox reaction?

Answer 9

• A reaction where electrons are being transferred

- Reduction and oxidation take place simultaneously

Question 10

What is a reducing agent?

Answer 10

A substance which donates electrons and becomes oxidised as it reduces another species

Question 11

What is an oxidising agent?

Answer 11

A substance which accepts electrons and becomes reduced as it oxidises another species

Question 12

Why do elements in diatomic molecules have an oxidation state of 0?

Answer 12

They haven’t accepted/donated any electrons

Question 13

What oxidation state do elements in diatomic molecules have?

Answer 13

0

Question 14

What oxidation state does fluorine have?

Answer 14

-1

Question 15

What oxidation state does chlorine have?

Answer 15

-1 (except with O or F)

Question 16

What oxidation state does oxygen have?

Answer 16

-2 (except with F or a peroxide)

Question 17

What oxidation state does bromine have?

Answer 17

-1 (except with O, F or Cl)

Question 18

What oxidation state does iodine have?

Answer 18

-1 (except with O,F,Cl or Br)

Question 19

What oxidation state does hydrogen have?

Answer 19

+1 (except with metals)

Question 20

What oxidation state do Group 1 metals have?

Answer 20

+1

Question 21

What oxidation state do Group 2 metals have?

Answer 21

+2

Question 22

What oxidation state does aluminium have?

Answer 22

+3

Question 23

What oxidation state do compounds have overall?

Answer 23

0

Question 24

What oxidation state do ions have?

Answer 24

The same as its charge

Question 25

How do you work out the oxidation state in a complex ion/compound?

Answer 25

- Multiply the oxidation number by the number of atoms present - Minus this value from the overall charge

Question 26

What elements have systematic names?

Answer 26

- Transition metals e.g lead | - Halogens

Question 27

How do you work out a compound's systematic name?

Answer 27

- Find which element has the variable oxidation state | - Work out its oxidation number

Question 28

What is an oxyanion?

Answer 28

A negative ion with oxygen in it

Question 29

What is a chlorate?

Answer 29

A compound made up of chlorine and oxygen ions

Question 30

What is the formula for a nitrate?

Answer 30

NO3-

Question 31

What is the oxidation state of a nitrate?

Answer 31

-1

Question 32

What is the formula for a sulfate?

Answer 32

SO4^2-

Question 33

What is the oxidation state of a sulfate?

Answer 33

-2

Question 34

What is the formula for a carbonate?

Answer 34

CO3^-2

Question 35

What is the oxidation state of a carbonate?

Answer 35

-2

Question 36

What is the formula of a hydroxide?

Answer 36

OH-

Question 37

What is the oxidation state of a hydroxide?

Answer 37

-1

Question 38

What is the formula of an ammonium ion?

Answer 38

NH4+

Question 39

What is the oxidation state of an ammonium ion?

Answer 39

+1

Question 40

What is the formula of a hydrogencarbonate?

Answer 40

HCO3-

Question 41

What is the oxidation state of a hydrogencarbonate?

Answer 41

-1

Question 42

What is the formula of a sulfide?

Answer 42

S^2-

Question 43

What is the oxidation state of a sulfide?

Answer 43

-2