Question

(1) (16 pts) Sugars can be digested aerobically (with oxygen) or anaerobically (e.g., by yeast). During aerobic digestion, sugars react with oxygen to form carbon dioxide and water. During anaerobic digestion, sugars can be decomposed by enzymes to create carbon dioxide and alcohols.

(a) (6 pts) Write the balanced chemical equation for aerobic digestion of glucose. C6H12O6(s). Identify the oxidizing and reducing agents in this reaction.

(b) (2 pts) Evaluate the number of moles of electrons transferred for the aerobic reaction in (a) for one mole of glucose at 25 degrees Celsius.

(c) (6 pts) Write the balanced chemical equation for anaerobic digestion of glucose. Assume that ethanol, C2H5OH(l), is the only alcohol product for anaerobic digestion. Identify the oxidizing and reducing agents in this reaction.

(d) (2 pts) Evaluate the number of moles of electrons transferred for the anaerobic reaction in (c) for one mole of glucose at 25 degrees Celsius.

Answer 1

Solution :-

(1) Sugars can be digested aerobically (with oxygen) or anaerobically (e.g., by yeast). During aerobic digestion, sugars react with oxygen to form carbon dioxide and water. During anaerobic digestion, sugars can be decomposed by enzymes to create carbon dioxide and alcohols.

(a) (6 pts) Write the balanced chemical equation for aerobic digestion of glucose. C6H12O6(s). Identify the oxidizing and reducing agents in this reaction.

Balanced reaction equation for the aerobic digestion is as follows

C6H12O6(s) + 6O2(g) ---- >6CO2(g) + 6H2O(l)

Oxidizing agent is = O2

Reducing agent is = C6H12O6

(b) (2 pts) Evaluate the number of moles of electrons transferred for the aerobic reaction in (a) for one mole of glucose at 25 degrees Celsius.

In the aerobic digestion reaction oxidation state of the carbon changed from 0 to +4

There are total 6 carbon atoms involved in the reaction therefore the number of electros transferred are (6*4) = 24 electrons per mole of glucose

(c) (6 pts) Write the balanced chemical equation for anaerobic digestion of glucose. Assume that ethanol, C2H5OH(l), is the only alcohol product for anaerobic digestion. Identify the oxidizing and reducing agents in this reaction.

Balanced reaction equation is as follows

C6H121O6(s) + yeast   ----- >2C2H5OH(l) + 2CO2(g)

Oxidizing agent = C6H12O6

Reducing agent = C6H12O6

(d) (2 pts) Evaluate the number of moles of electrons transferred for the anaerobic reaction in (c) for one mole of glucose at 25 degrees Celsius.

The number of electrons transferred in the process are calculated as follows

2 carbon atoms increased in oxidation state from 0 to +4

Therefore total number of electrons transferred are (4*2)= 8 electrons per mole of glucose