Answers section
Questions 6.3.1(b)
- State the function of concentrated sulphuric acid in this set-up. Name an alternative substance for concentrated sulphuric acid.
- Write equation for the reaction between hydrochloric acid and calcium carbonate.
- Name the method of delivery shown in the diagram.
- Explain why this method of delivery is suitable for collecting carbon (IV) oxide.
- What is the effect of the gas on wet blue litmus paper? What does this show?
- What is the effect of inverting the gas jar over the flame of a burning candle?
- Normally carbon (IV) oxide does not support burning. But ignited magnesium continues to burn in carbon (IV) oxide with a very hot flame. Suggest a reason for this. What are the other observations? Identify the other products observed.
Answers to Questions 6.3.1(b)
- To dry the gas, carbon (IV) oxide. Anhydrous calcium chloride is an alternative for concentrated sulphuric acid.
- CaCO3(s) + 2HCl(aq) ⟶ CaCl2(aq) + H2O(l) + CO2(g)
- Downward delivery (or upward displacement of air).
- Carbon (IV) oxide is denser than air.
- Wet blue litmus turns red or pink. It shows that carbon (IV) oxide is acidic.
- The flame goes off (It is extinguished).
- The hot flame breaks (decomposes) carbon (IV) oxide into the elements carbon and oxygen. Other observations are white powder and black specks. Identities of the other products are: white powder is magnesium oxide; black specks are carbon