1. Use Q=mcΔT and c=4.18J/°C/g. 25cm³ of sulfuric acid is put into a boiling tube. The starting temperature is 21°C. A spatula of iron filings is added. After a while the temperature reaches 33°C. What is the total heat energy change?

Question 1 of 16

2. 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?

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3. What does the symbol ΔH mean

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4. In a chemical reaction, 250 kJ/mol is taken to break all the bonds and 280 kJ/mol is released when new bonds are formed. What is the overall molar enthalpy of the reaction?

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5. Assuming bond energies in kJ/mol: H-C 412, C-C 348, O-H 463, C-O 360, C=C 612. Calculate the molar enthalpy change for the reaction: ethanol → ethene + water

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6. Is breaking bonds exothermic or endothermic?

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7. In a calorimetry experiment to investigate the heat energy released by the combustion of ethanol, why should the water in the calorimeter be stirred?

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8. 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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9. What is meant by the term exothermic?

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10. What is meant by the term endothermic?

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11. What does this diagram represent?

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12. Are neutralisation reactions exothermic or endothermic?

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13. When a solid dissolves, is this process exothermic or endothermic?

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14. Explain, in terms of making and breaking bonds, why a reaction could be exothermic

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15. Explain why experimental values of enthalpy change differ from theoretical values

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16. State the units of molar enthalpy change.

Question 16 of 16