O levels Chemistry CAQ

Note: In Pure Chemistry, most questions are based on table and diagram analysis, whereas the following are concept-based questions. Chapter 1 Experimental Chemistry Q: Name the method to collect ammonia gas [1]- Upwards delivery method Q: Name the method to collect Chlorine gas [1]- Downward delivery method Q: Name the method to collect hydrogen gas [1]- Water displacement method Q: Suggest a method to separate iron filings from sand [1]- Magnetic attraction Q: Suggest how pure copper(II) sulfate crystals can be obtained from its solution [3]- Gently heat the solution until the solution becomes saturated . Cool the solution and Copper(ii) sulfate crystals will form . Filter the saturated solution , and copper(ii) sulfate crystals are obtained as residue . Wash the copper(ii) sulfate crystals with little distilled water and dry it on sheets of filter paper . Q: How to separate oil from water . [1]-

Using a separating funnel. Since water is denser , it will be on the bottom , while oil is at the top . Q: How to identify colourless substances in a chromatography test . [1]- Use Ultraviolet light and locating agents Q: suggest the purpose of boiling chips in fractional distillation. [1] - To ensure smooth and even heating Q: Describe how the chromatography of a pure substance will look like . [1] One dot on the chromatogram . Chapter 2 Kinetic particle theory Q: Describe the movement and arrangement of a solid . [3]- Particles of a solid are arranged in a very closely packed and orderly manner. Particles can only vibrate about their fixed positions . Q: Describe the movement and arrangement of a liquid. [3]- Particles of a liquid are arranged in a closely packed and disorderly manner . Particles can slide past each other . Q: Describe the movement and arrangement of a gas. [3]- Particles of a gas are far apart and disorderly . Particles of gas move around freely and randomly in all directions .

Q: Describe the change in movement and arrangement when a substance changes from solid to liquid state. [4]- As temperature increases , particles gain more kinetic energy and vibrate faster about their fixed positions , eventually , the particles with increased kinetic energy overcome the strong forces of attraction and change to liquid state . Movement of particles change from vibrating about their fixed position to being able to slide past each other . Arrangement of particles also