This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
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Here are the solutions to your questions: QUESTION 9 9.1 Explain, in words, the meaning of an emf of 12 V. An electromotive force (emf) of 12 V means that the battery supplies 12 Joules of electrical energy to every 1 Coulomb of charge that passes through it. This energy is converted from chemical energy within the battery. 9.2 Calculate the current that passes through the electrical device. Step 1: Use the power formula for the electrical device. The power dissipated by the electrical device is given as P_device = 5 W, and its resistance is R_device = 5 . The formula for power is P = I^2 R. P_device = I_device^2 R_device 5 W = I_device^2 (5 ) I_device^2 = 5 W5 I_device^2 = 1 A^2 I_device = sqrt(1 A)^2 I_device = 1 A 9.3 Calculate the resistance of resistor R_x. The total current flowing from the battery is I_total = I_device = 1 A. The battery has an emf of 12 V and an internal resistance r = 1 . Step 1: Calculate the total resistance of the circuit. The total resistance R_total is given by Ohm's law for the entire circuit: emf = I_total R_total. R_total = emfI_total R_total = 12 V1 A R_total = 12 Step 2: Calculate the total external resistance R_ext. The total resistance is the sum of the external resistance and the internal resistance: R_total = R_ext + r. R_ext = R_total - r R_ext = 12 - 1 R_ext = 11 Step 3: Calculate the equivalent resistance of the parallel combination, R_parallel. The external circuit consists of the electrical device (R_device = 5 ) in series with a parallel combination of resistors. R_ext = R_device + R_parallel 11 = 5 + R_parallel R_parallel = 11 - 5 R_parallel = 6 Step 4: Use the parallel resistance formula to find R_x. The parallel combination consists of two branches: Branch 1: R_1 = 4 + R_x (since switch S is closed). Branch 2: $R_2 = 3 ✂️ _That answer was long and got cut off. Reply continue and I'll finish it._