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
An experiment is set up to determine the relationship between the DEGREE OF DIFFRACTION and WAVELENGTH of light. Blue light is passed through a single slit and the pattern formed is observed. The experiment is now repeated with green light and then with red light. The distance between the light source and the slit remains … Read more
7.1.1 Write down the equation of asymptote of g. (1) 7.1.2 Write down the range of g. (1) 7.1.3 Determine the coordinates of the x and y-intercepts of g. (3) 7.1.4 Hence, write down the values of x for which g(x) < 0. (1) 7.2 Draw a neat sketch of the graph of h(x) = … Read more
7.1 Sulphuric acid is a strong acid present in acid rain. It ionises in two steps as follows: 7.1.1 Define an acid in terms of the Lowry-Brønsted theory. (2) 7.1.2 Write down the FORMULA of the conjugate base of H3O+(aq). (1) 7.1.3 Write down the FORMULA of the substance that acts as an ampholyte in … Read more
Three small identical metal spheres, P, S and T, on insulated stands, are initiallyneutral. They are then charged to carry charges of -15 x 10-9 C, Q and +2 x 10-9 Crespectively, as shown below. The charged spheres are brought together so that all three spheres touch each otherat the same time, and are then … Read more
QUESTION 7 (Start on a new page.) A hydrogen bromide solution, HBr(aq), reacts with water according to the followingbalanced chemical equation: The Ka value of HBr(aq) at 25 °C is 1 x 109. 7.1 Is hydrogen bromide a STRONG ACID or a WEAK ACID? Give a reason for the answer. (2) 7.2 Write down the … Read more
7.1 A small sphere, Y, carrying an unknown charge, is suspended at the end of a light in extensible string which is attached to a fixed point. Another sphere, X, carrying a charge of +6 x10-6 C, on an insulated stand is brought close to sphere Y. Sphere Y experiences an electrostatic force and comes … Read more