10 minutes maximum! (can you do it in 5?) Grab a calculator and Periodic Table - time for some maths!
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1. The equation to calculate percentage yield is ….
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2. Tungsten metal was produced by reducing tungsten fluoride with hydrogen. A student calculated that a mass of 52.0g of tungsten should be formed. He actually obtained 43.2g of tungsten.
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Q3+4: A student synthesized 12.3g of aspirin from 13.8g of salicylic acid. He calculated that the maximum possible mass of aspirin which he could obtain was 18.0g. |
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3. a possible reason for the student obtaining less aspirin than expected is …
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4. The percentage yield of aspirin in this experiment was ……..
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Q5+6. 21.7g of mercury(II)oxide was decomposed by heating and 9.0g of mercury was collected. The equation for the reaction is: 2HgO (s) → 2Hg (l) + O2 (g) |
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5. The mass of 1 mole of mercury(II)oxide and the number of moles in 21.7g is ….
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6. The maximum mass of mercury which could be obtained in this experiment and the % yield are ….
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Q7+8. 50g of calcium carbonate was strongly heated resulting in thermal decomposition. CaCO3 (s) → CaO (s) + CO2 (g)
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7. What is the molar mass of calcium carbonate and how many moles of CaCO3 are in 50 g?
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8. What mass of calcium oxide is obtained from the thermal decomposition of 50 g of calcium carbonate if the reaction has a 40% yield?
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Q9+10. N2 + 3H2 ⇌ 2NH3 |
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9. The maximum possible yield of ammonia, if the reaction went to completion, is …….
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10. The percentage yield of ammonia in this reaction is …..
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