Physical Science

The balanced equation for the reaction of carbon with steam is as follows: C(s) + H2O(g) → CO(g) + H2(g) The graph below, NOT drawn to scale, represents the change in potential energy ofthe substances during the reaction. 7.1 Define the term heat of reaction. (2) 7.2 Is the reaction ENDOTHERMIC or EXOTHERMIC? Give a … Read more

6.1 Potassium permanganate, KMnO4, burns with a bright flame when a few drops of glycerine are added to it. The incomplete equation for the reaction is: 6.1.1 Define the term molar mass. (2) 6.1.2 The composition of glycerine is as follows: 39,13% carbon; 8,7% hydrogen; 52,17% oxygen Determine the EMPIRICAL formula of glycerine. Show ALL … Read more

An unknown mass of gas is sealed in container M. The temperature is increased andthe pressure inside the container is measured.The experiment is now repeated using the same mass of the same gas in a differentcontainer, N.The results obtained are represented in the sketch graph below. 5.1 Determine the value of X as shown on … Read more

The melting points and boiling points of four substances (A, B, C and D) are shown inthe table below. 3.1 Define the term melting point. (2) 3.2 Explain the difference in melting points of HF and HCℓ by referring to theTYPE of intermolecular forces. (4) 3.3 Which ONE of the substances (A, B, C or … Read more

2.1 Ammonia NH3(g) and hypochlorous acid HOCℓ(ℓ) are both examples ofcovalent compounds. 2.1.1 Define the term bonding pair. (2) 2.1.2 Draw Lewis structures for the following molecules: (a) NH3 (2)(b) HOCℓ (2) 2.1.3 Write down the: (a) Number of bonding pairs in NH3 (1)(b) Number of lone pairs on the oxygen atom in HOCℓ (1)(c) … Read more

Various options are provided as possible answers to the following questions. Choose   the answer and write only the letter (A–D) next to the question numbers (1.1 to 1.10) in the ANSWER BOOK, e.g. 1.11 E. Each question has only ONE correct answer. 1.1 The number of valence electrons in a silicon atom is … A … Read more

Three resistors, of resistances 3 Ω, 4 Ω and 6 Ω, and a bulb are connected in a circuit,   as shown below. Initially all the switches, S1, S2 and S3, are open. The internal resistance of the battery and the resistance of the connecting wires may be ignored. 10.1 State Ohm’s law in words. (2) … Read more

A coil with 200 windings and a surface area of 2,8 × 10-3 m is rotated at constant speed   in a constant magnetic field of 2,5 T. An emf of 3,5 V is induced in the coil. 9.1 Consider the following statement: The magnitude of the induced emf across  the ends of a conductor is … Read more