Redox

Question 1

define oxidising agent

Answer 1

oxidises another substance by accepting electrons, becoming reduced itself

Question 2

define reducing agent

Answer 2

reduces another substance by giving it electrons, becoming oxidised itself

Question 3

define disproportionation

Answer 3

the same element in a reaction is simultaneously reduced and oxisidsed

Question 4

oxidation number of uncombined elements

Answer 4

0

Question 5

oxidation number of monoatomic ions

Answer 5

same as charge

Question 6

oxidation number of group 1 and 2 elements

Answer 6

+1 and +2 respectively

Question 7

oxidation number of hydrogen

Answer 7

always +1 except in metal hydrides (NaH, CaH2) where its -1

Question 8

oxidation number of fluorine

Answer 8

always -1

Question 9

oxidation number of Oxygen

Answer 9

-2, except in peroxides (O2^2-) -1 or when bonded to fluorine, +2

Question 10

in half equations what do you use to balance oxygen

Answer 10

H2O

Question 11

in half equations what do you use to balance hydrogen

Answer 11

H+

Question 12

in half equations what do you use to balance charge

Answer 12

e-

Question 13

how do you balance half equations in alkaline conditions

Answer 13

by balancing any H+ with OH-

Question 14

what makes a substance a good reducing agent

Answer 14

low electronegativity

Question 15

what makes a substance a good oxidising agent

Answer 15

high electronegativity

Question 16

what does oxidation number show

Answer 16

• no of electrons an atom has lost or gained and is often shown in roman numerals

Question 17

sum of oxidation numbers in a compound =

Answer 17

its charge