OCR A Jan 2013 Paper 1 Q1

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Answer all the questions. Tungsten metal is used in the manufacture of some types of steel. Tungsten has an atomic number of 74. (a) Tungsten has many isotopes. (i) Explain what is meant by isotopes.[1] (ii) The mass number of one isotope of tungsten is 184. Complete the table below to show the atomic structure of this tungsten isotope. Protons Neutrons Electrons [1] (iii) What is used as the standard measurement of relative isotopic mass?[1] (b) In the manufacture of tungsten metal, an oxide of tungsten, WO3, is reacted with hydrogen gas. WO3(s) + 3H2(g) W(s) + 3H2O(g) (i) Using oxidation numbers, show what has been oxidised and what has been reduced in this reaction. oxidisedreduced[2]OCR 2013<br />
 (ii) A chemist reacts 11.59 g of WO3 with hydrogen gas. Calculate the volume of hydrogen gas, in dm3, required to completely react with this mass of WO3 at room temperature and pressure. volume of hydrogen gas =dm3 [3] [Total: 8]OCR 2013 Turn over<br />

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