Redox 1

Question 1

What is an oxidation number?

Answer 1

The number of electrons an atom uses to bond with any other atom

Question 2

What is the oxidation number of an uncombined element such as C, H, O2?

Answer 2

0

Question 3

What is the oxidation number of combined oxygen such as in H2O?

Answer 3

-2

Question 4

Oxidation number of oxygen in peroxides

Answer 4

-1

Question 5

What is the oxidation number of combined hydrogen such as in NH3, H2S

Answer 5

+1

Question 6

What is the oxidation number of combined hydrogen such as in metal hydrides, LiH

Answer 6

-1

Question 7

Oxidation number of a simple ion

Answer 7

Charge on the ion.
Na=+1
Cl=-1

Question 8

What is the oxidation numberNof combined fluorine such as in NaF, CaF2

Answer 8

-1

Question 9

When an element has more than one stable oxidation number how is it indicated?

Answer 9

Written as a roman numeral

Question 10

What is the oxidation number of Fe in iron (Ill) chloride?

Answer 10

+3

Question 11

What are oxyanions

Answer 11

Negative ions that have an element along with oxygen

Question 12

Oxidation number of S in SO4 2-

Answer 12

+6
Because, combined oxygen has an oxidation number of -2.
4 X-2 =-8.
The charge on the compound is -2. Sum of oxidation numbers must
equal -2
SO, -2-(-8) = +6

Question 13

Define oxidation in terms of electron transfer and oxidation number

Answer 13

Oxidation is
- loss of electrons
- increase in oxidation number

Question 14

Define reduction in terms of electron transfer and oxidation number

Answer 14

Reduction is
-gain of electrons
- decreased oxidation number

Question 15

What is a redox reaction

Answer 15

A reaction where both oxidation and reduction take place

Question 16

Oxidation number of a metal

Answer 16

0 because it is an element

Question 17

What is an oxidising agent

Answer 17

Species that gains electrons

Question 18

What is a reducing agent

Answer 18

Species that loses electrons

Question 19

Oxidation state of chlorine in NaClO

Answer 19

+1

Question 20

Define disproportionation

Answer 20

same species undergoes oxidation and reduction simultaneously

Question 21

Ocidation state of P in PCl5

Answer 21

+5

Question 22

Oxidation state of nitrogen in ammonia

Answer 22

+3

Question 23

Oxidation state of arsenic in AsO4 3-

Answer 23

+5

Question 24

Oxidation state of iron in K4Fe(Cn)6

Answer 24

2+

Question 25

6 type of ionic equations

Answer 25

Dissociation into ions Displacement reactions Redox Metal reacts with acid Neutralisation Precipitation

Question 26

What is dissociation

Answer 26

Particles in a substance spread out when heated or dissolved

Question 27

Ionic compounds are always ….. but ……. In water

Answer 27

Solid Dissolve

Question 28

Ionic equation for barium chloride dissociation into ions

Answer 28

BaCl2(aq)+aq—> Ba2+(aq) + 2Cl-(aq)

Question 29

Ionic equation of magnesium and copper sulfate displacement reaction

Answer 29

Mg(s) + CuSO4(aq)—> MgSO4 (aq) + Cu(s) Mg(s) + Cu2+(aq)—> Mg2+ + Cu(s)

Question 30

Ionic equation of sodium chloride and silver nitrite redox reaction

Answer 30

NaCl(aq) + AgNO3(aq)—> NaNO3 (aq) + AgCl(s) Cl- + Ag+ —> AgCl(s)

Question 31

Ionic equation of magnesium and sulfuric acid metal reacts with acid

Answer 31

Mg(s) + 2H+ —> Mg2+(aq) + H2(g)

Question 32

Ionic equation sodium hydroxide and sulfuric acid neutralisation

Answer 32

2OH-(aq) + 2H+ —> 2H2O(l)

Question 33

Ionic equation of lead nitrate and potassium iodide precipitation reaction

Answer 33

Pb2+(aq) + 2I- —> PbI2(s)

Question 34

Oxidation agent

Answer 34

Species that accepts electrons, undergoes reduction

Question 35

Reducing agent

Answer 35

Gives away electrons, undergoes oxidation

Question 36

Oxidation number rules

Answer 36

Uncombined elements=0 Ions made of just one atom = charge on the ion Sum of all oxidation states in a compound= 0 Sum of oxidation states of a complex ion = charge on ion

Question 37

Acids we must know

Answer 37

HCl hydrochloric acid H2SO4 sulfuric acid HNO3 nitric acid

Question 38

Alkalis we must know

Answer 38

NaOH KOH Ca(OH)2

Question 39

What is disproportionation reaction

Answer 39

Same species is oxidised and reduced at the same time

Question 40

Oxidation state of iron in Fe2O3

Answer 40

+3

Question 41

Oxidation state of chromium in Cr2O7 2-

Answer 41

+6

Question 42

Balance this redox reaction H2SO4–>H2S

Answer 42

H2SO4 + 8e- + 8H+ —>H2S + 4H20

Question 43

Balance this redox reaction NO3 - —> NO2

Answer 43

NO3- + 2H+ +e- —> NO2 + H2O