Chemical reactions

Question 1

Acid base reaction

Answer 1

Transfer of proton from acid to base

Question 2

Acid + metal hydroxide (or oxide)

Answer 2

Metal salt and water

Question 3

Acid + metal carbonate

Answer 3

Metal salt + CO2 + H2O

Question 4

Acid + metal sulfide

Answer 4

Metal salt + hydrogen sulfide (H2S)

Eg. 2HCl + FeS —> FeCl2 + H2S

Question 5

Reduction and oxidation define

Answer 5

OIL RIG
oxidation is loss
Reduction is gain (of electrons)

Oxidation = lose e, gain Ox, ox no increase, remove H

Red = gain e, lose Ox, ox no decrease, gain H

Question 6

Reactive metal and water

Answer 6

—> metal HYDROXIDE and H2

Eg Ca + H2O —> Ca(OH)2 + H2

In G2, only Mg makes Oxide + H2

Question 7

Metal and oxygen

Answer 7

Metal oxide

Question 8

Heat a metal carbonate

Answer 8

Thermal decomposition into metal OXIDE and CO2

Question 9

Heat metal hydrogen carbonate G1 and G2

Answer 9

Thermal decomposition

G1 Metal CARBONATE + CO2 + H2O
G2 metal OXIDE + CO2

Question 10

Heat metal hydroxide

Answer 10

Metal OXIDE and H2O

Alkali metals stable to heat

Question 11

Common oxidants are…

Answer 11

Oxygen and non-metals

oxygen to oxide ion

Iodine, chlorine to ion

Hydrogen peroxide to water

Permanganate to manganese

Dichromate your chromium

Question 12

Common reductants

Answer 12

Hydrogen and metals

Metal to metal ion

Carbon to carbon dioxide

Hydrogen to water

Sulfite to sulfate (gain ox)

More reactive metal, the better the reductant

Question 13

Reduction half equation permanganate

Answer 13

MnO4- + 8H+ + 5e- —> Mn2+ + 4 H2O

5 electrons

Question 14

Dichromate reduction half equatio

Answer 14

(Cr2O7)2- + 14H+ + 6e- —> 2Cr3+ + 7H2O

6 electrons

Question 15

Disproportionation

Answer 15

Can oxidise and reduce itself

A redox reaction in which the same element is both oxidised and reduced

Eg hydrogen peroxide (ON -1)

H2O2 to O2 (ON 0, oxidised, reductant)

H2O2 to H2O (ON -2, reduced, oxidant)

Question 16

Warm an alkali metal hydroxide and ammonium salt

Answer 16

Metal salt + ammonia + water

Question 17

Metal oxide and water

Answer 17

Metal hydroxide

Only GI and GII

Question 18

Oxidation number of an element

Answer 18

0

Question 19

Oxidation numbers in a molecule

Answer 19

Add to 0

Question 20

Oxidation numbers in an ion

Answer 20

Oxidation number is the charge of the ion

Question 21

Ox number in polyatomic ion

Answer 21

Add to the charge of the ion

Question 22

Oxidation number of oxygen

Answer 22

Always -2 EXCEPT in peroxides

Eg. H2O2
Where it is -1

Question 23

Ox number H in compounds

Answer 23

Always +1
(With more electroneg, non metals)
In metal hydrides Eg. NaH
M it is -1

Question 24

The oxidation of F in compounds

Answer 24

Always -1

Question 25

NO2 gas colour

Answer 25

Brown

Question 26

Metal nitrite + water

Answer 26

Metal hydroxide + NH3

Question 27

Spontaneous reaction define

Answer 27

A reaction that favours the formation of products at the conditions under which the reaction is occurring
IN TERMS OF ENTHALPY??

Question 28

4 common STRONG acids

Answer 28

HCl
HNO3
H2SO4
HBr

Question 29

3 common weak acids

Answer 29

HF
HCOOH
CH3COOH

Question 30

strong bases formula

Answer 30

OH is in the formula

eg. NaOH –> Na+ + OH-
do not need H2O as a reactant

Question 31

Weak bases

Answer 31

OH not in formula, needs water as a reactant.

eg. ammonia NH3 + H2O = NH4+ + OH-

methanamine CH2NH2 + H2O = CH3NH3+ + OH-

Question 32

acidic/basic salts

Answer 32

dissociate first. Carboxylic salts, metal carbonates, ammonium salts (AMMONIUM ion is the one that further reacts with water)

NaCH3COO –> Na+ + CH3COO-
CH3COO- + H2O = CH3COOH + OH-

Na2CO3 –> 2Na+ + CO3(2-)
CO3(2-) + H2O = OH- + HCO3-