Method Temperature / °C Catalyst fermentation 30 none (yeast used) steam and ethene 300 phosphoric acid The table compares the conditions used in two method...
Question 1 Report
| Method | Temperature / °C | Catalyst |
|---|---|---|
| fermentation | 30 | none (yeast used) |
| steam and ethene | 300 | phosphoric acid |
The table compares the conditions used in two methods of making ethanol. Which method needs a high temperature together with a catalyst?
Answer Details
Compare both columns for each row. Fermentation is run at only 30 degrees Celsius, and its catalyst column shows none, because the enzymes come from yeast rather than from a chemical catalyst. Adding steam to ethene is run at 300 degrees Celsius, ten times hotter, and uses phosphoric acid, so that is the method needing both a high temperature and a catalyst. Choosing both methods ignores that 30 degrees Celsius is barely above room temperature and that no chemical catalyst is listed against fermentation. The high temperature is needed because adding water across the double bond of ethene in the gas phase is otherwise slow, and the acid catalyst speeds it further without being used up.
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