Required practicals 🥼🧪

Question 1

What is a [short and basic] method to produce, pure dry crystals?

Hint: dilute solution, filtered off, saturated solution heated and warm place.

Answer 1

1) excess [magnesium carbonate) added to dilute solution, until no more dissolves. (Shows no more is reacting).

2) excess magnesium carbonate is flitered off.

3) saturated solution heated for a few minutes (to evaporate some of the water).

4) leave in a warm place until dry crystals are formed, or until the crystals can be dried on fliter paper.

Question 2

What’s a key feature about a salt ?

Answer 2

• a salt, always contains a positive ion.
• For example in copper sulphate, the positive ion is the metal ion: Cu2+
• ; salts also contain a negative ion. For example, in copper sulphate: SO4^2-

Question 3

What is a full method to produce, pure dry crystals?

Hint: dilute solution, filtered off, saturated solution heated and warm place.

Answer 3

1) start with a fixed volume of dilute sulcuric acid-[this is our limiting reactant]

2) then gently heat the acid, until almost boiling.

3) using a spatula, add small amounts of copper oxide to the acid and stir the solution sith a glass rod. [solution should turn blue and copper oxide should seem to dissapear]

4) if the solution contuines to be clear blue, contuine adding copper oxide and stop adding copper oxide, if some powder remains after stirring.

5) unreacted copper oxide is flitered off, using a filter funnel and filter paper

6) place the solution in an evaporating basin and heat gently over a beaker of boiling water- heat until half of the solution remains

7) then leave the solution for 24 hours, in a cool palace for copper sulphate crystals to form.

8) finally, scrape the crystals on get paper towel and gently pat them dry.