ES 2- Bromine From Sea Water

Question 1

Define oxidation state

Answer 1

How many electrons have been gained or lost compared to the unreacted atom

Question 2

In reduction, oxidation number…

Answer 2

Decreases

Question 3

What is the oxidation number of an uncombined element?

Answer 3

0

Question 4

What is the oxidation number of combined oxygen?

Answer 4

-2
EXCEPT in peroxides (H2O2) = -1
In compounds with F = +2

Question 5

What is the oxidation number of combine hydrogen?

Answer 5

+1

EXCEPT in metal hydrides (NaH) = -1

Question 6

What is the oxidation number of a simple ion?

Answer 6

Charge on ion

Question 7

What is the oxidation number of combined fluorine?

Answer 7

-1

Question 8

What is the oxidation number of group 1 elements?

Answer 8

+1

Question 9

What is the oxidation number of group 2 elements?

Answer 9

+2

Question 10

What is the oxidation number of sulphur in SO2?

Answer 10

S - 4 = 0

S = +4

Question 11

What does the Roman numerals show in iron(II) chloride?

Answer 11

Oxidation number of iron is +2

Question 12

What is oxidation number of Cr in K2Cr2O7?

Answer 12

K = +2
O = -2
2 + Cr2 -14 = 0
Cr = +6

Question 13

Define oxyanion

Answer 13

Negative ion that contains oxygen

Question 14

What does -ate in a name indicate?

Answer 14

Presence of oxygen

Question 15

Are reducing agents oxidised or reduced?

Answer 15

Oxidised, they reduce other species

Question 16

How would you use oxidation stages to balance an equation?

Answer 16

1. Identify how oxidation states for each element has changed
2. Balance equation so number of electrons gained and lost is equal