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Dodaj cały arkusz do zestawuAn unknown organic compound, X, contains only carbon, hydrogen and oxygen. Elemental analysis shows that it contains 54.5 % carbon and 36.3 % oxygen by mass. (i) Determine the empirical formula of X. The mass spectrum of X is shown. (ii) Identify the species…
A sample of 0.296 g of a volatile organic liquid, Y, was vaporized completely at 87.0 °C and 100.0 kPa. The volume of the vapour was 123 cm3. Determine the molar mass of Y.
In air, sulfur dioxide can be oxidized to sulfur trioxide. The reaction is reversible, and at high temperature it reaches equilibrium in a closed container. 2 SO2(g) + O2(g) ⇌ 2 SO3(g) (i) At 600 °C the equilibrium constant, K, for this reaction is…
Ozone, O3, is formed in photochemical smog from oxygen molecules and oxygen atoms. Deduce the Lewis structure of ozone.
The two O-O bonds in ozone have the same length, 1.28 × 10−10 m. For comparison, an O-O single bond is 1.48 × 10−10 m long and an O=O double bond is 1.21 × 10−10 m long. (i) Suggest what the bond…
Acid deposition forms when oxides of sulfur dissolve in water in the atmosphere. Write an equation for sulfur(VI) oxide reacting with water to produce an acid.
A dilute aqueous solution of potassium iodide, KI(aq), is electrolysed using inert graphite electrodes, as shown in the diagram. (i) State the direction in which the electrons move in the external circuit, and the direction in which the positive ions and the…
The concentration of dissolved oxygen in a sample of pond water was determined by the Winkler method. The reactions that take place are:…
Tellurium has atomic number 52. Using the position of tellurium in the periodic table, deduce two features of its electron configuration.
Outline why copper is malleable.
A 15.40 g block of pure copper is heated from 20.0 °C to 45.0 °C. Calculate the heat energy absorbed, in J. The specific heat capacity of copper is 0.385 J g−1 K−1.
Neon has three naturally occurring isotopes, , and . (i) Identify the technique used to determine the relative abundances of the isotopes of neon. A sample of neon contains 90.2 % of , 0.3 % of…
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.
Suggest how the rate of this reaction could be determined experimentally.
Explain how a catalyst such as manganese(IV) oxide increases the rate of this reaction.
Propanoic acid reacts with methanol to produce an ester. (i) Draw the full structural formula of the organic product. (ii) Predict the number of signals, and their splitting patterns, in the 1H NMR spectrum of this ester. (iii) The chemical shifts in…
(i) Write the equation for the complete combustion of propan-1-ol, CH3CH2CH2OH. (ii) Determine the enthalpy change, in kJ mol−1, for the combustion of gaseous propan-1-ol to give gaseous carbon dioxide and gaseous water, using bond…
Identify the type of reaction.
Two products are possible in this reaction. (i) Explain the mechanism for the formation of the major product, using curly arrows to show the movement of electron pairs. (ii) Explain why the mechanism results in one product being formed in greater quantity than…
Draw the structure of a section of the polymer formed from three pent-1-ene monomers.
Deduce the hybridization of carbon atoms 1 and 2 in pent-1-ene.
Describe, in terms of the orbitals involved, the bonding between carbon atoms 1 and 2 in pent-1-ene.
One of the two products of the reaction of pent-1-ene with HCl can exist as stereoisomers. Draw the three-dimensional structures of the two stereoisomers, using wedge-dash notation, and show clearly the relationship between them.
Explain why the lattice enthalpy of potassium bromide, KBr, is lower than that of sodium bromide, NaBr.
Nickel forms the chloride NiCl2. (i) State the full electron configuration of the nickel(II) ion, Ni2+. (ii) In aqueous solution nickel(II) ions exist as [Ni(H2O)6]2+, which is green. Describe the interaction between the nickel ion and a…
The initial rate of the iodination of propanone in aqueous acid was measured at constant temperature. CH3COCH3(aq) + I2(aq) → CH3COCH2I(aq) + HI(aq) Four experiments were carried out and the results are given in the table. Deduce the overall rate…
The rate of a different reaction at 45 °C is four times its rate at 25 °C. Calculate the activation energy, in kJ mol−1, for this reaction, using sections 1 and 2 of the data booklet.