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 ?)

what is h20

1) Ethanol is made by the fermentation of sugar.

(a) Suggest a temperature for carrying out the fermentation and explain your answer.

The temperature for carrying out fermentation to produce ethanol is typically around 30-35°C. This temperature range is optimal because it allows for the efficient activity of the enzymes responsible for the fermentation process. Enzymes are biological catalysts that help speed up chemical reactions. They have specific temperature ranges in which they are most active. In the case of fermentation, the enzymes responsible for converting sugar into ethanol work best within the mentioned temperature range. Higher temperatures can denature the enzymes, preventing them from functioning properly. Conversely, lower temperatures can slow down the reaction and decrease the fermentation rate. Therefore, maintaining a temperature around 30-35°C promotes optimal enzyme activity and enhances the efficiency of the fermentation process.

(b) Why is it important that air does not enter the flask?

It is important to prevent air from entering the flask during fermentation for a couple of reasons. Firstly, air contains oxygen, which can hinder the fermentation process. The presence of oxygen can promote the growth of aerobic microorganisms, such as bacteria and yeast, that consume ethanol instead of producing it. This can lead to decreased ethanol yield and contamination of the final product.

Secondly, air typically contains various other microorganisms, including molds and bacteria, that can spoil the fermentation process and compromise the quality of the ethanol produced. These unwanted microorganisms can introduce off-flavors, odors, or even toxins into the fermentation system.

Therefore, by maintaining a controlled environment within the flask, free from air and its associated microorganisms, one can ensure a successful and uncontaminated fermentation process, leading to the production of high-quality ethanol. To achieve this, an airlock or an airtight seal can be used to allow the release of carbon dioxide produced during fermentation while preventing air from entering the flask.

2) Methanol burns in oxygen to make carbon dioxide and water. The equation is exothermic, with 1452 kJ/mol of energy being released.
(a) Write a balanced equation for the combustion of methanol.

The balanced equation for the combustion of methanol is:
2CH3OH + 3O2 → 2CO2 + 4H2O

(b) State how much energy (in kJ) is released when 1 mole of methanol is burned.

The equation states that 1452 kJ of energy is released when 1 mole of methanol is burned.

(c) Calculate the amount of heat energy released on burning 4 moles of methanol.

To calculate the amount of heat energy released on burning 4 moles of methanol, we can use the stoichiometry of the balanced equation. According to the equation, 2 moles of methanol produce 1452 kJ of energy. Therefore, for 4 moles of methanol, we can calculate:

Energy released = (1452 kJ * 4 moles) / 2 moles
Energy released = 2904 kJ

So, on burning 4 moles of methanol, 2904 kJ of heat energy is released.

(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)

The molar mass of methanol (CH3OH) is 32 g/mol.

To calculate the energy release when 4g of methanol is burned, we need to determine the number of moles of methanol in 4g:

n = m / Mr
n = 4g / 32 g/mol
n = 0.125 mol

Now we can use this value to calculate the energy release:

Energy released = 1452 kJ/mol * 0.125 mol
Energy released = 181.5 kJ

So, when 4g of methanol is burned, approximately 181.5 kJ of heat energy is released.

(e) Calculate the mass of carbon dioxide produced when 16g of methanol is used. (use n = m/Mr)

Using the balanced equation, we can see that 2 moles of methanol produce 2 moles of carbon dioxide. Therefore, the ratio of methanol to carbon dioxide is 1:1.

To calculate the mass of carbon dioxide produced when 16g of methanol is used, we need to determine the number of moles of methanol:

n = m / Mr
n = 16g / 32 g/mol
n = 0.5 mol

Since the ratio of methanol to carbon dioxide is 1:1, the mass of carbon dioxide produced is also 16g.

Therefore, when 16g of methanol is used, 16g of carbon dioxide is produced.