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An alloy of magnesium and aluminium is used for car wheels and laptop casings. (i) Suggest why adding aluminium produces a material that is harder and less malleable than magnesium alone. (ii) Suggest why a magnesium alloy is a good choice for the casing of a…
Sodium reacts vigorously with water. (i) Write an equation, with state symbols, for the reaction of sodium with water. (ii) Describe one observation from the reaction in (i). (iii) Sketch, on the axes below, an energy profile for this reaction. Label the…
Which statement about the visible line emission spectrum of atomic hydrogen is correct? A. The lines are equally spaced because the energy levels are equally spaced B. The lines get closer together towards longer wavelength because the energy levels converge…
Complete the table for Trial 1 and so determine its Ka value. Use section 1 of the data booklet.
Ka was also calculated for Trials 2 and 3, and the experimental error was found for each, as shown in the table. Determine the experimental error for Trial 1, using a literature value of Ka = 1.35 × 10−5 for propanoic acid. If…
Comment on how the uncertainty of the pH probe affects the accuracy of the Ka values obtained.
Silver has two stable and abundant isotopes. Its relative atomic mass is 107.87. (i) Determine the percent abundance of each isotope, showing your working. (ii) State the number of protons, neutrons and electrons in .
(i) Outline why the strength of the metallic bond increases from potassium, K, to calcium, Ca. (ii) Write an equation for the reaction of potassium, K, with water, including state symbols. (iii) Outline why the electronegativity of chlorine is greater than…
Steel is an alloy of iron with a small percentage of carbon. (i) Outline one reason why steel is harder than pure iron. (ii) State one property of iron, other than hardness, that can be modified by forming an alloy.
Iron and nickel can be used to design a voltaic cell. Fe(s) + Ni2+(aq) → Fe2+(aq) + Ni(s) (i) Annotate the diagram with the appropriate electrodes, electrolyte solutions and the direction of electron flow. (ii) The redox reactions in some voltaic…