Random stuff

Question 1

What is an isotope

Answer 1

Isotopes are atoms of the same element that have the same number of protons but a diff number of neutrons

Question 2

What is relative atomic mass

Answer 2

Average mass of a particular element compared to 1/12 of a carbon-12 atom

Question 3

What is relative molecular mass

Answer 3

Average mass of one molecule compared to 1/12 of a carbon-12 atom

Question 4

Solubility table: Nitrates

Answer 4

All nitrates are soluble

Question 5

Solubility table: Halides

Answer 5

All halides are soluble except Lead (II) and Silver

Question 6

Solubility table: Sulfates

Answer 6

All sulfates are soluble except Barium, Lead (II) and Calcium

Question 7

Solubility table: Carbonates

Answer 7

All carbonates are insoluble except grp 1 metals and ammonium

Question 8

Solubility table: Oxides and hydroxides

Answer 8

All oxides and hydroxides are insoluble except grp 1 metals and ammonium

Barium and Calcium are sparingly soluble

Question 9

Preparation of salts: Precipitation

(Both reactants must be aqueous)

If one is solid, another reaction has to be carried out to change that into aqueous

Answer 9

1. Mix the two solutions in a beaker. Stir with a glass rod to ensure a complete reaction.
2. Filter out the precipitate using a filter funnel and filter paper
3. Wash the residue by running distilled water through it
4. Allow the salt to dry between sheets of filter paper

Question 10

Preparation of salts: Reaction of acid with excess insoluble reactant

(Dilute acid + Insoluble base, carbonate or metal (EXCESS))

Answer 10

1. Warm a sample of the acid in a beaker. Add an EXCESS of insoluble reactant to beaker containing acid
2. Stir with a glass rod to ensure complete reaction
3. Filter the mixture and collect the filtrate
4. Heat filtrate in evaporating dish till saturation is reached
5. Allow solution to cool so that crystals can form
6. Allow the salt to dry between sheets of filter paper

Question 11

Preparation of salts: Titration

Answer 11

1. Using a pipette, measure out a fixed volume of acid. Transfer the solution to a conical flask
2. Add a few drops of indicator e.g. Methyl Orange
3. Using a burette, add the alkali drop by drop until indicator changes colour permanently
4. Note down the volume of alkali required for complete neutralisation
5. Repeat the titration, this time without an indicator. Stop burette when the reading reaches the same level as earlier noted

Question 12

Acid + Metal ->

Answer 12

Salt + Hydrogen

Question 13

Acid + Carbonate ->

Answer 13

Salt + Water + Carbon dioxide

Question 14

Acid + Base ->

Answer 14

Salt + Water

Question 15

Acid + Ammonium salt ->

Answer 15

Salt + ammonia + water