IGCSE Chemistry Experimental techniques topical questions

A student investigates a reaction that produces a gas and heats up over time.

1. (a)Name the apparatus used to measure exactly 25.0 cm³ of solution.[1]
2. (b)Name the apparatus used to follow the temperature change.[1]
3. (c)Name the apparatus used to collect and measure the volume of gas produced.[1]

A mixture of sand and salty water is filtered.

1. (a)Name the solid collected on the filter paper.[1]
2. (b)Name the liquid that passes through the filter paper.[1]

A student carries out four measurements during an experiment.

1. (a)Name the apparatus used to add acid drop by drop while recording the volume.[1]
2. (b)Name the apparatus used to measure roughly 150 cm³ of water.[1]
3. (c)Name the apparatus used to time how long a reaction takes.[1]
4. (d)Name the apparatus used to find the mass of a beaker.[1]

Pure water is needed from an aqueous solution of copper(II) sulfate.

1. (a)Name the separation technique used.[1]
2. (b)Describe how the technique separates the water from the dissolved salt.[2]
3. (c)Name what remains in the flask at the end.[1]

Chromatography is carried out on four samples of ink, A, B, C and D, on the same sheet of paper. The solvent front moves 8.0 cm. Sample A has a spot 6.0 cm above the baseline.

1. (a)Calculate the Rf value of the spot in sample A.[1]
2. (b)Sample B shows two separate spots. State what this shows about B.[1]
3. (c)A known dye X gives a spot at exactly the same height as one spot of B. State what this suggests.[1]
4. (d)Explain why the starting line is drawn in pencil, not ink.[1]

Two gas jars are collected in the laboratory, one of oxygen and one of chlorine.

1. (a)Describe the test for oxygen, including the positive result.[2]
2. (b)Describe the test for chlorine, including the positive result.[2]

A mixture contains salty water with grains of sand suspended in it.

1. (a)Which laboratory technique separates an insoluble solid from a liquid?[1]
2. (b)Give the name given to the solid trapped by the filter paper and to the liquid that drips through it.[2]
3. (c)Describe how dry salt crystals are obtained from the liquid.[1]

A solution is known to contain one cation and one anion. The tests below are carried out.

1. (a)Identify the cation and explain how the tests show this.[2]
2. (b)Identify the anion.[1]
3. (c)Write the ionic equation for the white precipitate in the third test.[2]

A white powder, W, is analysed. A flame test on W gives a red flame. When dilute hydrochloric acid is added to W, the mixture fizzes and a gas is released that turns limewater milky.

1. (a)Identify the cation in W and state which test confirms it.[2]
2. (b)Identify the anion in W and give the reason from the observations.[2]
3. (c)Name the compound W could be.[1]

A solution is known to contain just one of the cations Li⁺, K⁺, Ca²⁺ or Ba²⁺. A flame test on the solution gives an orange-red flame.

1. (a)Identify the cation, giving your reason.[2]
2. (b)Describe how the flame test should be carried out.[2]
3. (c)Explain why the wire is first cleaned with concentrated hydrochloric acid and heated until no colour shows.[1]