The reaction between dichromate ions (Cr2O7-2) and iron(II) ions (Fe2+) in an acidic medium is given below. 9.1 Determine the oxidation number of CHROMIUM in Cr2O7-2(aq).(2) 9.2 Define reduction in terms of electron transfer.(2) 9.3 Write down the FORMULA of the substance that undergoes oxidation. Explainthe answer in terms of oxidation numbers.(2) 9.4 Write down … Read more
9.1 Oxidation numbers make it easier to determine whether an element or a substance is oxidised or reduced during a chemical reaction. 9.1.1 Define the term oxidation with reference to oxidation numbers. (2) 9.1.3 Calculate the oxidation number of oxygen in H2O2. (1) 9.2 Consider the UNBALANCED equation below: Fe2+(aq) + Cℓ2(g) → Fe3+(aq) + … Read more
9.1 A survey was done among 80 learners on their favourite sport The results are shown below : 52 learners like rugby (R) 42 learners like volleyball(V) 5 learners like chess (C) 14 learners like rugby and volleyball but not chess 12 learners like rugby and chess but not volleyball 15 learners like volleyball and … Read more
An induction coil of area 48,6 cm2 and 200 windings is rotated clockwise in a constant magnetic field of magnitude 2,4 T. Refer to the diagram below. The graph below shows how the induced emf varies with the inverse of time. 9.1 State Faraday’s law in words. (2) 9.2 Use the information in the graph … Read more
The sketch below shows the graph of the function f(𝑥) = a𝑥2 + b𝑥 +c. The straight line with equation 3y = 𝑥 – 5 intersects f at B. The points A(-2;0) and B are the 𝑥-intercepts of f . Point D(-1;3)is a point on f . 9.1 Determine the coordinates of B.(2) 9.2 Determine … Read more
9.1 In the diagram O is the centre of the circle and ABC are points on the circle. Use the diagram in your SPECIAL ANSWER BOOK to prove that:AÔB = 2AĈB. (6) 9.2 In the figure below, DĈO = 25° and O is the centre of the circle. A, B, E C and D are … Read more
In the diagram ∆LNR is drawn with points L and R on the circumference of a circle. NR cuts the circle at M. K is a point on LR with KN the bisector of LN̂R. KN cuts the chord LM at O. LK = LO. LÔK = 65° and KN̂M = 25°. 9.1 Prove that … Read more
A packet of sweets contains 3 pink, 2 green and 5 blue sweets. Two sweets are removed in succession from the packet without replacing them. 9.1 Draw a tree diagram to determine all possible outcomes. (6) 9.2 Determine the probability that: (Round of your answer to three decimal places) 9.2.1 Both sweets are blue (2) … Read more
Study the water cycle below and answer the questions that follow. 9.1 The water cycle consists of many processes.Identify the following processes: 9.1.1 A (1) 9.1.2 B (1) 9.1.3 E (1) 9.2 Is energy ABSORBED or RELEASED during condensation? Give a reason forthe answer. (2) 9.3 Give ONE reason why water vapour is referred to … Read more