Download Tutorial 92C - Ethanol

 Year 12 Chemistry Tutorial 9.2.C – Ethanol Module 9.2 – Production of Materials Topic 9.2.C – Ethanol Name 1.
Date Write equations for the following reactions, naming the products. (a) the dehydration of 2-­‐butanol …………………………………………………………………………………………………………………………………………………………………………………… (b) the hydration of 1-­‐pentene …………………………………………………………………………………………………………………………………………………………………………………… (c) the dehydration of 3-­‐hexanol …………………………………………………………………………………………………………………………………………………………………………………… (d) the hydration of 2-­‐propene …………………………………………………………………………………………………………………………………………………………………………………… (e) the fermentation of glucose …………………………………………………………………………………………………………………………………………………………………………………… (f) the combustion of ethanol …………………………………………………………………………………………………………………………………………………………………………………… 2.
The table below shows the solubility of some alcohols in water. Name Formula Solubility (g/100g water) Methanol CH3OH Miscible in all proportions Ethanol CH3CH2OH Miscible in all proportions 1-­‐propanol CH3CH2CH2OH Miscible in all proportions 1-­‐butanol CH3CH2CH2CH2OH 8.0 1-­‐pentanol CH3CH2CH2CH2CH2OH 2.7 1-­‐hexanol CH3CH2CH2CH2CH2CH2OH 0.6 (a) Write a generalised statement relating to the solubility in water to the size of the molecule. …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… (b) What type of bonding is used to explain the solubility of the smaller alcohols? …………………………………………………………………………………………………………………………………………………………………………………… (c) Explain why the alcohols with the longer carbon chain are less soluble in water. …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… 3.
Ethanol and water readily dissolve in each other (miscible), as do ethanol and hexane; however, water and hexane do not dissolve in each other (immiscible). (a) Explain why ethanol is miscible in both water and hexane, but water and hexane do not mix. …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… (b) Considering your answer to (a), suggest why ethanol is a solvent widely used in industry. …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… 4.
Ethanol has been promoted as an alternative fuel to petrol because it is a renewable resource. (a) Explain why ethanol is a renewable resource yet petrol is a non-­‐renewable resource. …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… Page 2 (b) List two advantages and two disadvantages of using ethanol as a fuel. …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… 5.
Fermentation provides a small proportion of industrial alcohol and all of the beverage alcohol. (a) List the starting ingredients for fermentation to occur. …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… (b) What conditions are necessary for successful fermentation? …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… (c) What additional problems exist if ethanol is to be produced from the cellulosic component of the waste left over from sugar refining? …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… 6.
Define the molar heat of combustion of a compound. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. Page 3 7.
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The molar heat of combustion of ethanol is 1360 kJ mol . What will be the final temperature if 250 g of water at 20°C is heated by the combustion of 2.0 g of ethanol if there is a 30% heat loss to the surroundings? The specific heat of water is -­‐1 -­‐1
4.12 J K g . …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. A group of students were conducting a calorimetric experiment to determine the molar heat of combustion of ethanol. They used 200 g of water in a can and heated it using a spirit burner. The mass of the spirit burner and ethanol at the beginning of the experiment was 82.5 g and at the end the mass was 81.2 g. The water temperature increased by 26°C. (a) Calculate the student's experimental value for the molar heat of combustion of ethanol. …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… (b) When the student consulted the textbook they found the accepted value for the heat of combustion of ethanol to -­‐1
be 1360 kJ mol . Suggest reasons for the difference between their value and the accepted value. …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… (c) Suggest two changes that could be made to the experiment to improve the accuracy of the results. …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………………………………… Page 4 9.
Compare the use of ethanol to petrol as a car fuel. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. 10. Evaluate the use of ethanol as an additive to petrol for use in car engines. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. Page 5 11. Outline the major steps involved in producing ethanol from the waste products of sugar refining. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………………………………………………………………………………… Page 6