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Chromium(III) oxide, Cr2O3, is a hard ceramic used as an abrasive and as a wear-resistant coating. Outline the bonding in chromium(III) oxide and its electrical conductivity in the solid state. Use sections 9 and 17 of the data booklet.
A conductivity probe is used to follow the concentration of sodium chloride in dilute aqueous solutions. A solution of concentration 0.015 mol dm−3 gives a conductivity of 1.8 mS cm−1. On the axes, draw a graph of conductivity…
(i) Bronze, an alloy of copper and tin, is used for ship propellers and bearings. Explain, by referring to its structure, why bronze is less malleable than pure copper. (ii) In a separate process, zinc is removed from a copper-zinc alloy by reaction with…
A steel cylinder of volume 5.0 dm3 holds 2.0 g of helium at 27 °C. Ar(He) = 4.0; R = 8.31 J K−1 mol−1; PV = nRT Which expression gives the pressure of the helium, in Pa? A.…
In a titration, 25.00 cm3 of a 0.120 mol dm−3 solution of a weak monoprotic organic acid, HA, was neutralized by adding sodium hydroxide solution, NaOH(aq), from a burette. The pH curve obtained is shown. Determine the concentration,…
Outline how 0.100 mol dm−3 solutions of ethanoic acid and nitric acid could be told apart.
A sample of element X consists of two isotopes. Their mass numbers and relative abundances are given in the table. What is the relative atomic mass of X? A. 69.0 B. 69.8 C. 70.0 D. 70.2
A simplified overall process produces the ester C5H10O2 as the desired product: 2 C3H5ClO + 2 C2H6O + Ca(OH)2 → 2 C5H10O2 + CaCl2 + 2 H2O The molar masses of C3H5ClO, C2H6O, Ca(OH)2 and C5H10O2 are respectively 92.52,…
Which statement correctly compares infrared and ultraviolet radiation? A. Infrared radiation has a longer wavelength and a lower photon energy than ultraviolet radiation. B. Infrared radiation has a longer wavelength and a higher frequency than ultraviolet…
Beeswax contains esters that form when long-chain carboxylic acids react with long-chain alcohols. State the name of this type of reaction.