MODULE 2 -2.1.4 acids

Question 1

What are acids?

Answer 1

Proton donors (H+)

Question 2

What are bases?

Answer 2

Proton acceptors

Question 3

What happens when acids and bases react?

Answer 3

Forms a reversible reaction

Question 4

What is an alkali?

Answer 4

A soluble base that produces -OH ions

Question 5

Give an example of a weak acid

Answer 5

Ethanoic acid (CH3COOH)

Question 6

Give an example of a strong acid

Answer 6

HCl, H2SO4, HNO3

Question 7

Give an example of a strong base

Answer 7

NaOH, KOH

Question 8

Give an example of a weak base

Answer 8

NH3

Question 9

Polyprotic acids

Answer 9

Acids that can donate more than one proton e.g HNO3 is monoprotic (1 mol of H+), H2SO4 is diprotic (2 mol of H+), H3PO4 (3 mol of H+),

Question 10

What are salts?

Answer 10

Neutral compounds formed from acid and bases

Question 11

Equation for metals and acid

Answer 11

METAL + ACID -> SALT + HYDROGEN

Question 12

Equation for metal oxides and acids

Answer 12

METAL OXIDE + ACID -> SALT + WATER

Question 13

Equation for metal hydroxides and acids

Answer 13

METAL HYDROXIDE + ACID -> SALT + WATER

Question 14

Equation for metal carbonates and acids

Answer 14

METAL CARBONATE + ACID -> SALT + CO2 + WATER

Question 15

The mole equation for solutions

Answer 15

n = concentration (moldm-3) x volume (dm3)

Question 16

What are titrations used for?

Answer 16

Finding out the concentration of an acid of alkali

Question 17

How do you carry out a titration?

Answer 17

1. Have an acid/alkali with a known concentration in a burette
2. Add the chemical in the burette to the conical flask until UI changes colour (end point)
3. Add drop by drop
4. Add an acid/ alkali with an unknown concentration but known volume into conical flask and UI
5. Read how much chemical was added from the burette to neutralise the chemical.
6. Read bottom of meniscus at eye level
7. Record results to 2dp to get concordant results

Question 18

How do you make standard solutions?

Answer 18

1. Weigh the amount with balance
2. Transfer solid to beaker
3. Dissolve solid with water and stir
4. Transfer to volumetric flask with funnel. Rinse beaker and glass rod
5. Fill water to graduation line and use pipette if needed
6. Invert flask and put lid onto ensure thorough mixing