1)Ethanol is made by the fermentation of sugar.

(a)Suggest a temperature for carrying out the fermentation and explain your answer. -40°C(ish), ??to do with enzymes; they can't or don't work as well in other temps./controls the speed of fermentation
(b)Why is it important that air does not enter the flask? -

2)Methanol burns in oxygen to make carbon dioxide and water. The equation is exothermic, with 1452kJ/mol. of energy being released.
(a)Write a balanced equation for the combustion of methanol.
-methanol+oxygen=carbon dioxide+water
-CH3OH+O2=CO2+H2O
?(b)State how much energy (in kJ) us released when 1 mole of methanol is burned.
?(c)Calculate the amount of heat energy released on burning 4 moles of methanol.
(d)What is the molar mass of methanol?(=32) Use the value to calculate the energy release when 4g of methanol is burned. (use n=m/Mr ?)
(e)Calculate the mass of carbon dioxide produced when 16g of methanol is used. (use n=m/Mr ?)

Fermentation is usually carried out at around 70 degrees F. The lower the temperature, the slower the process. Fermentation is an anaerobic process. If air/oxygen enters the flask then bacteria may grow and spoil the fermentation process.

1a) The suggested temperature for carrying out the fermentation of sugar to produce ethanol is around 30-35°C. This temperature range is optimal for the activity of the enzymes responsible for fermentation. Enzymes are biological catalysts that speed up chemical reactions. They are highly sensitive to temperature and have an optimal temperature at which they work most efficiently.

At lower temperatures, such as -40°C, the enzymes become less active and their catalytic ability decreases. The reaction rate of fermentation slows down significantly, leading to a slower conversion of sugar to ethanol. Conversely, at higher temperatures, the enzymes can become denatured, losing their structure and function, and thus becoming ineffective in catalyzing the fermentation process.

1b) It is important that air does not enter the flask during fermentation because the presence of oxygen can inhibit the fermentation process. When oxygen is present, it can act as an alternative electron acceptor for the yeast cells, diverting them from producing ethanol. This phenomenon is known as aerobic respiration, where sugar is converted into carbon dioxide and water instead of ethanol. To ensure the desired ethanol production, the flask must be sealed to prevent the entry of air and the promotion of aerobic respiration. This allows the yeast to carry out anaerobic fermentation, converting sugar into ethanol and carbon dioxide.

2a) The balanced equation for the combustion of methanol is:

CH3OH + O2 -> CO2 + H2O

2b) To determine the amount of energy released when 1 mole of methanol is burned, we reference the given energy value of 1452 kJ/mol. This means that for every mole of methanol combusted, 1452 kJ of energy is released.

2c) To calculate the amount of heat energy released from burning 4 moles of methanol, we can multiply the given energy value by the number of moles:

4 moles x 1452 kJ/mol = 5808 kJ

Therefore, 5808 kJ of heat energy would be released when 4 moles of methanol are burned.

2d) The molar mass of methanol is stated as 32 g/mol. Using this value, we can calculate the energy release when 4 grams of methanol is burned. To do this, we need to know the number of moles of methanol in 4 grams.

Using the formula n = m / Mr, where n represents moles, m represents mass, and Mr represents molar mass:

n = 4g / 32 g/mol = 0.125 moles

Now, we can calculate the energy release for 0.125 moles of methanol:

0.125 moles x 1452 kJ/mol = 181.5 kJ

Thus, 181.5 kJ of heat energy would be released when 4 grams of methanol are burned.

2e) To calculate the mass of carbon dioxide produced when 16 grams of methanol is burned, we first need to determine the number of moles of methanol in 16 grams.

Using the same formula as before:

n = 16g / 32 g/mol = 0.5 moles

Since the chemical equation tells us that 1 mole of methanol produces 1 mole of carbon dioxide, we can directly relate the moles of methanol to the moles of carbon dioxide.

Therefore, the mass of carbon dioxide produced would be:

0.5 moles x 44 g/mol = 22 grams