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Which statement best explains why the first ionization energy of aluminium is lower than that of magnesium? A. Aluminium has more protons than magnesium B. Aluminium has a smaller atomic radius than magnesium C. The outer electron of aluminium is in a 3p…
(i) Draw one Lewis (electron dot) structure of the sulfate ion. (ii) Calculate the percentage of oxygen present in the double salt. (iii) Determine the empirical formula of the double salt. Use section 7 of the data booklet. (iv) The molar mass of the…
A 1.50 g sample of the double salt was dissolved in distilled water. Aqueous barium chloride was then added in excess, so that all the sulfate ions were precipitated as barium sulfate. (i) Formulate an ionic equation, including state symbols, for…
The graph shows the successive ionization energies of an element in period 3. Which element is it? A. Si B. P C. S D. Cl
The concentration of an ethanoic acid solution was found by titration with a 0.150 mol dm−3 standard solution of potassium hydroxide, KOH(aq), using an indicator to detect the end point. (i) Calculate the pH of the potassium hydroxide solution.…
Write an ionic equation that explains why an aqueous solution of potassium ethanoate is not neutral.
Copper(II) ions can be removed from waste water by chelation. A possible ligand is the nitrilotriacetate anion, shown. Identify the atoms in the ligand that form coordination bonds with a copper(II) ion when it forms a complex ion.
Which of the following statements can be deduced from the period in which an element is placed? I. The number of occupied main energy levels II. The number of protons in the nucleus III. The number of electrons in the outer energy level A. I only B. I and II…
Hydrogen sulfide, H2S, is removed from natural gas by burning it in air to form sulfur dioxide. (i) Determine the standard enthalpy change of reaction, ΔH⊖, in kJ mol−1, for 2 H2S(g) + 3 O2(g) → 2 SO2(g) + 2 H2O(l),…
The enthalpy change of combustion of ethanol was investigated in a school laboratory. A spirit burner containing ethanol was used to heat water in a metal can. A total of 0.0250 mol of ethanol was burned. The following data were recorded. (i) Calculate the…