Acids

Question 1

Name the formulae for hydrochloric sulfuric nitric phosphoric methanoic ethanoic propanoic ACIDS

Answer 1

Question 2

What is an acid

Answer 2

Releases H+ ions in aq solution

Question 3

What is a strong acid ?
What is a weak acid?

Answer 3

Strong - completely dissociate when dissolved in water (into ions)

Weak-slightly dissociates into ions when dissolved in water

Question 4

What is a base

Answer 4

A substance which neutralises an acid (reacts w an acid)

Question 5

What is an alkali

Answer 5

A soluble base that releases OH- ions in aq solution

Question 6

Give some examples of bases

Answer 6

Metal oxide metal hydroxide metal carbonate ammonia

Question 7

What do alkalis produce

Answer 7

OH- ions (either dissociate or react w water to form these)

Question 8

How are salts formed

Answer 8

Neutralisation

Question 9

What is a salt

Answer 9

Hydrogen of acid replaced with metal or cation

Question 10

What are the 4 ways to form salts and what is formed with each way

Answer 10

Acid + base —> salt + water
Acid + alkali —> salt + water
Acid + carbonate —> salt + CO2+ water
Acid + ammonia —> ammonium salt

Question 11

What do ionic equations show

Answer 11

A species that changes state in a reaction

Question 12

When there is a precipitate in a reaction what is an easier way to write the ionic equations?

Answer 12

If AgCl is formed write the ions that form it so
Ag+ + Cl- —> AgCl

Question 13

How do you make a standard solution ( Acid base titration)

Answer 13

Question 14

What is a meniscus

Answer 14

The bottom of curve

Question 15

Why is titration used?

Answer 15

A solution of know conc is used to determine the conc of an unknown solution

Question 16

What indicator is used in titration and what are the colours in acid alkali and at the end

Answer 16

PHENOLPHTHALEIN
ACID- COLOURLESS
ALKALI- PINK
END- pale pink

Question 17

What are the 2 steps of titration

Answer 17

1. Rough titration - to determine approximate standard solution you need to neutralise unknown solution
2. More accurate titrations that are used in calculations

Question 18

Write the steps for titration for HCl (unknown conc) and NaOH (known conc)

Answer 18

1. pour HCl into beaker and transfer 25 cm3 to a confocal flask using a Pipette
2. Fill burette with NaOH solution and record initial reading on burette ro 2 dp
3. Add few drops of phenolphthalein indicator to flask
4. Add NaOH to flask using tap Untill colour changes from colourless to pink ( neutralisation )
5. Record final reading of burette to 2dp and find titre (initial - end)

Question 19

How do you find the 2 concordant results ?

Answer 19

The 2 titres within 0.1cm3 of each other

Question 20

Which 2 titres are used to calculate the mean titre

Answer 20

The 2 concordant results