1. To determine the formula of a metal oxide by combustion, magnesium is heated in a crucible. Why is a lid used?

Question 1 of 17

2. A sample of carbon contained 98.90% carbon-12 and 1.10% carbon-13. Calculate the relative atomic mass of carbon

Question 2 of 17

3. Complete the following expression: amount (in moles) =

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4. What mass of carbon dioxide is produced when 24g of carbon undergoes completely combustion?

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5. Calculate the relative formula mass(Mr) of zinc phosphide (Zn₃P₂)

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6. A graph shows the solubility of sodium chloride in water at 50°C is 34g/100g. At that temperature, what mass of sodium chloride will dissolve in 200g water?

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7. In a chemical reaction, the overall molar enthalpy is -87 kJ/mol. Is this reaction exothermic or endothermic?

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8. In the thermal decomposition of calcium carbonate, we might expect 50g of calcium carbonate to produce 28g of calcium oxide. If instead only 24g of calcium oxide is produced, what is the percentage yield?

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9. What are the units for amount in Chemistry?

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10. In a combustion calorimetry experiment, 0.78g of ethanol (C₂H₅OH) produced 12,540 J of heat energy. Calculate the molar enthalpy change.

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11. What is the empirical formula of a compound in which 0.48 g of carbon combines with 0.08 g of hydrogen and 0.64 g of oxygen?

Question 11 of 17

12. Use Q=mcΔT and c=4.18J/°C/g. A spatula of sodium fluoride is put into a boiling tube with 25cm³ of water. The temperature drops from 22.0°C to 18.6°C. What is the total heat energy change?

Question 12 of 17

13. An oxide of nitrogen contains 26% nitrogen and 74% oxygen and has a relative molecular mass of 108. Find the empirical and molecular formulae for the oxide.

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14. What volume does 0.5 moles of ethene gas occupy (at rtp)

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15. What is meant by the term empirical formula?

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16. Name this piece of lab equipment

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17. 0.5 dm³ of copper sulfate solution has a concentration of 0.1 mol/dm³. What amount of copper sulfate does it contain?

Question 17 of 17