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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…
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…
How many ions are present in 142 g of Na2SO4? M(Na2SO4) = 142 g mol−1 A. 1 B. 3 C. 6.02 × 1023 D. 1.81 × 1024
Calculate the pH of a 0.125 mol dm−3 solution of sodium hydroxide.
A sample of the sodium hydroxide solution is gradually added to 25.0 cm3 of an aqueous solution of an unknown organic acid, producing the following pH curve. Calculate the concentration of the unknown organic acid.
Which main energy level can hold a maximum of 50 electrons? A. n = 5 B. n = 4 C. n = 6 D. n = 25