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A block of zinc attached to a steel structure acts as a sacrificial anode. (i) Calculate the standard cell potential, in V, of a cell made from zinc and steel half-cells. Use section 19 of the data booklet and take the standard electrode potential of steel to…
The graph shows the volume of hydrogen produced when a small piece of zinc reacts with a large excess of 2.0 mol dm−3 hydrochloric acid. (i) Deduce from the graph how the rate of reaction depends on the amount of zinc present. (ii) The rate is…
A compound contains only carbon, hydrogen and oxygen. Complete combustion of 4.60 g of the compound produces 8.80 g of carbon dioxide and 5.40 g of water as the only products. Which is the empirical formula of the compound?…
Explain why the first ionization energy of magnesium is greater than that of sodium.
The diagram represents the electron energy levels in a hydrogen atom. (i) Suggest two features of the behaviour of electrons in atoms that this energy level model cannot explain or represent. (ii) Draw an arrow, labelled X, on the diagram to represent the…
A 7.60 g sample of an oxide of nitrogen contains 4.80 g of oxygen. What is the empirical formula of the oxide? A. N2O B. NO2 C. N2O3 D. N2O5
(i) Deduce the expression for the equilibrium constant, Kc, for this equation. (ii) State how the use of a catalyst affects the value of Kc. (iii) Using the reaction quotient, Q, explain why raising the pressure at constant temperature increases the…
The enthalpy change of the reaction is one factor that influences the position of equilibrium. (i) Determine the enthalpy change, ΔH, for the production of methanol, in kJ, using bond enthalpies. Use section 12 of the data booklet. (ii) Outline why a…
The standard free energy change, ΔG⊖, for the production of methanol is −44.0 kJ at 298 K and the standard enthalpy change, ΔH⊖, is −114 kJ. (i) State, with a reason, whether the production of methanol is spontaneous at 298 K.…
Which graph represents the relationship between the pressure, P, and the volume, V, of a fixed amount of an ideal gas at constant temperature, according to PV = nRT? A. Graph A B. Graph B C. Graph C D. Graph D