Neco 2022 Chemistry Question 8

The laboratory set‑up shown in the diagram is used to determine the solubility of calcium hydroxide, Ca(OH)₂, at 25 °C. The apparatus consists of a 250 mL beaker containing 200 mL of distilled water, a thermometer, a magnetic stirrer, a filter funnel fitted with filter paper, and a graduated cylinder. In the experiment, excess solid Ca(OH)₂ is added to the water and the mixture is stirred until no more solid dissolves (saturation). The suspension is filtered, and the filtrate is collected in the graduated cylinder. The following data are recorded: - Initial mass of Ca(OH)₂ added: 1.00 g - Mass of undissolved Ca(OH)₂ after filtration: 0.65 g - Volume of filtrate collected: 180 mL - Temperature of the solution: 25 °C Answer the questions below.