module 2 - acids and redox

Question 1

what do all acids contain in their formula?

Answer 1

hydrogen

Question 2

what does an acid release when dissolved in water?

Answer 2

hydrogen ions as protons into the solution

Question 3

write an equation to show how hydrogen chloride gas dissolves in water.

Answer 3

HCl (g) + aq —–> H+ (aq) + Cl- (aq)

Question 4

• formula of nitric acid?

- formula of ethanoic acid

Answer 4

• HNO3

- CH3COOH

Question 5

give an example of a strong acid?

Answer 5

HCl

Question 6

How far does a strong acid dissociate?

Answer 6

• it releases all its hydrogen atoms into solution as H+ ions and completely dissociates in aq solution

Question 7

write the equation for the dissociation of HCL

Answer 7

HCl (aq) —> H+ (aq) + Cl- (aq)

Question 8

give an example of a weak acid!

Answer 8

ethanoic acid

Question 9

How far does a weak acid dissociate?

Answer 9

• it only releases a small amount of hydrogen atoms into solution as ion
• it partially dissociates in aq solution

Question 10

write the equation for the dissociation of CH3COOH?

Answer 10

CH3COOH (aq) (equi arrow) H+(aq) + CH3COO- (aq)

Question 11

in ethanoic acid, which hydrogens are released as H+?

Answer 11

• the hydrogen atom on the COOH group is released as H+

Question 12

give 4 groups of bases!!

Answer 12

• metal oxides
• metal hydroxides
• metal carbonates
• ammonia (NH3)

Question 13

what is a base?

Answer 13

a compound that neutralises an acid to form a salt

Question 14

what is an alkali?

Answer 14

a base that dissolves in water to release OH- ions into solution

Question 15

write a formula showing the alkali sodium hydroxide dissolving in water

Answer 15

NaOH (s) + aq —-> Na+ (aq) + OH- (aq)

Question 16

give 3 metal oxide examples?

Answer 16

• MgO
• CaO
• CuO (copper oxide)

Question 17

give 3 metal carbonate examples?

Answer 17

• Na2CO3
• CaCO3 (calcium carb)
• CuCO3

Question 18

give 3 alkali examples?

Answer 18

• NaOH
• KOH
• NH3

Question 19

acid + base =

Answer 19

salt + water

Question 20

in a neutralisation reaction, what happens to the H+ ions?

Answer 20

they’re replaced by metal or ammonium ions from the base

seen as replacing the H in the formula too

Question 21

what salts does sulfuric, nitric and ethanoic acid make?

Answer 21

• sulfate
• nitrate
• ethanoate

Question 22

whats the formula for ammonium ethanoate?

Answer 22

CH3COONH4

Question 23

acid + metal oxide/hydroxide =

Answer 23

salt + water

Question 24

for alkali neutralisation reactions, what do the reactants have to be in?

Answer 24

solution (aq)

Question 25

acid + alkali =

Answer 25

salt & water

Question 26

what’s the ionic equation for most neutralisation reactions?

Answer 26

H+(aq) + OH-(aq) → H2O(l)

Question 27

acid + metal carbonate =

Answer 27

salt + water + carbon dioxide

Question 28

formula of magnesium chloride?

Answer 28

MgCl2

Question 29

is H2SO4 a strong acid? write equation for dissociation of H2SO4 in water

Answer 29

• yes, but only for 1 of the 2 hydrogen atoms
• H2SO4 (aq) —>H+ (aq) + HSO4- (aq)
• HS04- (aq) (equi arrow) H+ (aq) + SO4^2- (aq)
• the HSO4- ions behave as a weak acid after (most strong acids do this)