2015

Ammonia is an important fertiliser. Large amounts are prepared from hydrogen and nitrogen in industry. 10.1 For the industrial preparation of ammonia, write down: 10.1.1 The name of the process used (1) 10.1.2 A balanced equation for the reaction that occurs (3) 10.1.3 The source of nitrogen (1) 10.2 The yield of ammonia changes with … Read more

The simplified diagram below represents an electrochemical cell used for the purification of copper. 9.1 Define the term electrolysis. (2) 9.2 Give a reason why a direct-current (DC) source is used in this experiment. (1) 9.3 Write down the half-reaction which takes place at electrode A. (2) 9.4 Due to small amounts of zinc impurities … Read more

Learners are given the following two unknown half-cells: Half-cell 1: Q2+ (aq) | Q(s) Half-cell 2: Pt | R2(g) | R–(aq) During an investigation to identify the two half-cells, the learners connect each half-cell alternately to a Cd2+(aq) | Cd(s) half-cell under standard conditions. For each combination of two half-cells, they write down the net … Read more

7.1 Ammonium chloride crystals, NH4Cl(s), dissolve in water to form ammonium and chloride ions. The ammonium ions react with water according to the balanced equation below: 7.1.1 Write down the name of the process described by the underlined sentence. (1) 7.1.2 Is ammonium chloride ACIDIC or BASIC in aqueous solution? Give a reason for the … Read more

An unknown gas, X2(g), is sealed in a container and allowed to form X3(g) at 300 °C. The reaction reaches equilibrium according to the following balanced equation: 3X2(g) ⇌ 2X3(g) 6.1 How will the rate of formation of X3(g) compare to the rate of formation of X2(g) at equilibrium? Write down only HIGHER THAN, LOWER … Read more

Dilute acids, indicated in the table below, react with EXCESS zinc in each of the three experiments to produce hydrogen gas. The zinc is completely covered with the acid in each experiment. The volume of hydrogen gas produced is measured in each experiment. 5.1 Name TWO essential apparatuses needed to determine the rate of hydrogen … Read more

Four compounds of comparable molecular mass are used to investigate the effect of functional groups on vapour pressure. The results obtained are shown in the table below. 4.1 Define the term functional group of an organic compound. (2) 4.2 Which ONE of the compounds (A, B, C or D) in the table has the: 4.2.1 … Read more

3.1 The flow diagram below shows two organic reactions. The letter P represents an organic compound. Use the information in the flow diagram to answer the questions that follow. Write down the: 3.1.1 Type of reaction of which Reaction 1 is an example (1) 3.1.2 STRUCTURAL FORMULA of the functional group of ethyl propanoate (1) … Read more