Acids, Bases and Salts

Question 1

Explain the pH scale and how groups are identified

Answer 1

0= most acidic
6= least acidic
7= neutral (water)
8= least alkaline
14= most alkaline

Question 2

Explain concentration

Answer 2

A measure of the number of solute particles in a solution
High number of solute particles= concentrated
Low number of solute particles= dilute

Question 3

Acid+ metal—>

Answer 3

salt + hydrogen

Question 4

Acid+ base—>

Answer 4

salt + water

Question 5

Acid+ alkali—>

Answer 5

salt + water

Question 6

Acid+ metal carbonate

Answer 6

salt + water + carbon dioxide

Question 7

What is the name and ion for Nitric acid (HNO3)

Answer 7

Nitrates

ion= NO3-

Question 8

What is the name and ion for Sulfuric acid (H2SO4)

Answer 8

Sulfates

ion= SO42-

Question 9

What is the name and ion for Hydrochloric acid (HCl)

Answer 9

Chlorides

ion= Cl-

Question 10

What is the process of preparing salts from a metal or insoluble base/carbonate?

Answer 10

Evaporation

Question 11

What is the process of preparing salts from an alkali or soluble carbonate?

Answer 11

Titration

Question 12

What are the 3 stages of evaporation?

Answer 12

1. Excess metal/base/carbonate is added to the acid to make sure it has all reacted. Heating and stirring helps the process, and when the fizzing stops, you know the acid has all been reacted.
2. The mixture is filtered, so the excess solid remains in the filter paper. The salt solution passes through into the evaporating basin.
3. The salt crystals are collected from the solution by evaporation.

Question 13

What are the 8 stages to titration?

Answer 13

1. Use the pipette and pipette filler to add 25 cm3 of alkali to a clean conical flask.
2. Add a few drops of indicator and put the conical flask on a white tile.
3. Fill the burette with acid and note the starting volume.
4. Slowly add the acid from the burette to the alkali in the conical flask, swirling to mix.
5. Stop adding the acid when the end-point is reached (the appropriate colour change in the indicator happens).
6. Note the final volume reading.
7. Repeat steps one to five using the same volume of acid from the burette without using an indicator.
8. The resulting solution can then be evaporated to obtain pure crystals of the salt.

Question 14

How do you collect large crystals from evaporation?

Answer 14

Evaporate slowly near a window or radiator

Question 15

how do you collect small crystals from evaporation?

Answer 15

Use a Bunsen burner to evaporate 2/3 before allowing to crystalize naturally

Question 16

What is the equation for concentration (mol/dm3)

Answer 16

Concentration(mol/dm3)= amount in mol / volume in dm3

Question 17

How do you convert a volume into dm3 from cm3?

Answer 17

Divide by 1,000

Question 18

How do you get moles from grams?

Answer 18

Moles= mass (g) / formula mass