A student was given an image of a graph showing the volume of gas produced over time for a chemical reaction. They were asked to: a) determine when the reaction ended and the volume of gas produced af

The graph flattens at approximately 8 minutes.
The reaction came to an end at 8 minutes.

a) (ii)

At 3 minutes, the volume of gas produced is approximately 48 cm³.

b) (i) To prepare and collect a dry sample of ammonia gas, the reagents used are:

• Ammonium chloride
• Calcium hydroxide

b) (ii) The reaction condition for preparing ammonia gas is:

• Heating

b) (iii) Ammonia is collected by downward displacement of air because:

• Ammonia gas is less dense than air.

c) This question describes a titration experiment to determine the concentration of dilute sulphuric acid using a standard solution of sodium carbonate.
The requirements listed are:

• Beaker
• Pipette
• 250 cm³ volumetric flask
• Burette
• Conical flask
• Anhydrous sodium carbonate
• Wash bottle
• Dilute sulphuric acid
• Distilled water
• Phenolphthalein indicator

The task is to prepare 250 cm³ of 0.1 M $\text{Na}_2\text{CO}_3(\text{aq})$ and use this standard solution to determine the concentration of dilute sulphuric acid. This is a description of a practical procedure rather than a question requiring a numerical answer or explanation.