1)(a) A suitable temperature for carrying out the fermentation would be around 30°C to 37°C. This temperature range provides optimum conditions for the enzymes involved in the fermentation process. Most enzymes have a specific range of temperatures where they work most efficiently, and this range is typically close to the temperature of the organism's natural environment. If the temperature is too low or too high, the enzyme's activity can decrease or be denatured.
(b) It is important that air does not enter the flask because oxygen can interfere with the fermentation process. In the presence of oxygen, yeast can participate in aerobic respiration, which produces less ethanol than the desired fermentation process. Additionally, any exposure to oxygen can result in contamination by unwanted microorganisms or unwanted reactions occurring, producing undesirable byproducts.
2)(a) Balanced equation for the combustion of methanol:
CH3OH + 1.5 O2 → CO2 + 2 H2O
(b) The amount of energy released when 1 mole of methanol is burned is 1452 kJ.
(c) To calculate the heat energy released from burning 4 moles of methanol:
1452 kJ/mol × 4 mol = 5808 kJ
(d) The molar mass of methanol is 32 g/mol. To calculate the energy release when 4 g of methanol is burned, use n = m / Mr:
n = 4 g / 32 g/mol = 0.125 mol
Energy released: 0.125 mol × 1452 kJ/mol = 181.5 kJ
(e) To calculate the mass of carbon dioxide produced when 16g of methanol is used, first determine the moles of methanol:
n = 16 g / 32 g/mol = 0.5 mol
Since in the balanced equation, there is a 1:1 ratio between methanol and carbon dioxide, this means 0.5 moles of CO2 are produced.
The molar mass of carbon dioxide (CO2) is 44 g/mol, thus:
mass of CO2 = 0.5 mol × 44 g/mol = 22 g
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 ?)
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