2.1.4- Acids

Question 1

What does an acid release?

Answer 1

H+ ions in aqueous solutions

Question 2

What does an alkali release?

Answer 2

OH- ions in aqueous solutions

Question 3

What is an alkali?

Answer 3

A water soluble base

Question 4

What are some common acids?

Answer 4

-HCl
-H2SO4
-HNO3
-CH3COOH

Question 5

What are some common bases?

Answer 5

-NaOH
-KOH
-NH3 (ammonia)

Question 6

What does a strong acid do in aqueous solutions?

Answer 6

Fully dissociates

Question 7

What does a weak acid do in aqueous solutions?

Answer 7

Partially dissociates

Question 8

What is neutralisation?

Answer 8

The reaction of an acid and a base to form water and a salt

Question 9

What does an acid and a carbonate produce?

Answer 9

Salt + water + carbon dioxide

Question 10

What does an acid and a metal oxide produce?

Answer 10

Salt + water

Question 11

What does an acid and a metal produce?

Answer 11

Salt + hydrogen

Question 12

What is a titration?

Answer 12

A practical method where a standard solution of known concentration is reacted with a solution of unknown concentration in order to determine the concentration of this solution

Question 13

How do you make a standard solution?

Answer 13

1. Weight the solid on a balance
2. Add distilled water and stir with a glass rod until all the solid has dissolved
3. Transfer to a volumetric flask with washings
4. Make up to the 250cm^3 mark with distilled water
5. Shake flask

Question 14

What are common errors of measuring a standard solution?

Answer 14

-systematic errors on the balance
-lost substance in transfer
-overfilling the volumetric flask

Question 15

How can errors be reduced?

Answer 15

Using washing methods and by reading volumes from the bottom of the meniscus

Question 16

What is the titration process?

Answer 16

1. Fill the burette with the standard solution of known concentration, ensuring no air bubbles
2. Use a pipette filler and pipette to transfer 25cm^3 of the solution with unknown concentration into a conical flask
3. Add two or three drops of indicator
4. Record the initial burette reading
5. Titrage the contents of the conical flask by adding the solution to it from the burette until the indicator undergoes a permanent colour change
6. Record the final burette reading and calculate the titre volume
7. Repeat until at least two concordant results are obtained

Question 17

What is a concordant result?

Answer 17

Within 0.1cm^3 of eachother

Question 18

What is the best way to reduce uncertainties?

Answer 18

Increase the titre volume needed for the reaction by increasing the volume and concentration of the substance in the conical flask or by decreasing the concentration of the substance in the burette