The simplified diagram below represents an electrochemical cell used for the electrolysis of a concentrated sodium chloride solution, NaCℓ(aq). X and Y are carbon electrodes. 9.1 Define the term electrolysis. (2) 9.2 Chlorine gas, Cℓ2(g), is released at electrode X. Write down the:9.2.1 Letter (X or Y) of the electrode where oxidation takes place (1) … Read more
9.1 The simplified sketch of an electric motor is shown below. 9.1.1 Write down the energy conversion that takes place in this motor. (1) 9.1.2 Is the motor above an AC motor or a DC motor? (1) 9.1.3 What is the function of the commutator in this motor? (1) 9.2 A resistor Y is rated … Read more
The diagram below shows a simplified electrolytic cell used to electroplate a ring. 9.1 Define the term electrolyte. (2) 9.2 Is the pure chromium metal the ANODE or the CATHODE of the cell? Give a reason for the answer. (2) 9.3 Write down the half-reaction that takes place at the ring. (2) 9.4 Calculate the … Read more
The diagram below is a simplified representation of an AC generator. The coil isrotated in a clockwise direction in the magnetic field. 9.1 Write down the name of component X. (1) 9.2 Write down the function of component Y. (1) 9.3 Use the relevant principle to explain why an emf is induced in the coil … Read more
In the electrochemical cell below, carbon electrodes are used during the electrolysis of a concentrated sodium chloride solution. The balanced equation for the net (overall) cell reaction is: 2H2O(ℓ) + 2Cℓ ─(aq) → Cℓ2(g) + H2(g) + 2OH─(aq) 9.1 Is the reaction EXOTHERMIC or ENDOTHERMIC? (1) 9.2 Is electrode P the ANODE or the CATHODE? … 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
9.1 Learners investigated the relationship between potential difference (V) and current (I) for the combination of two resistors, R1 and R2. In one experiment, resistors R1 and R2 were connected in parallel. In a second experiment, resistors R1 and R2 were connected in series. The learners then plotted graph X, the results of one of … Read more
(Start on a new page.) 9.1 A generator is shown below. Assume that the coil is in a vertical position. 9.1.1 Is the generator above AC or DC? Give a reason for the answer. (2) 9.1.2 Sketch an induced emf versus time graph for ONE complete rotation of the coil. (The coil starts turning from … Read more
The simplified diagram below represents an electrochemical cell used in the refining of copper. One of the electrodes consists of impure copper. 9.1 What type of power source, AC or DC, is used to drive the reaction in this cell? (1) 9.2 When an electric current passes through the CuCl2(aq), the mass of electrode P … Read more
A battery with an internal resistance of 1 Ω and an unknown emf (ε) is connected in a circuit, as shown below. A high-resistance voltmeter (V) is connected across the battery. A1 and A2 represent ammeters of negligible resistance. With switch S closed, the current passing through the 8 Ω resistor is 0,5 A. 9.1 … Read more