the process of respiration, glucose is oxidized completely. In fermentation, O2 is absent, and glucose is broken down into Co2 and H2o.
Calculate delta g for respiration of 1.00 g of glucose
Calculate delta g for fermentation of 1.00 g of glucose.
My answers:
-16.0 kJ and -1.26 kJ
what I need help with is:
Calculate delta g for oxidation of the ethanol from part C.
answer in kJ/g..............thanks!
To calculate the delta G for the oxidation of ethanol from fermentation, we need to determine the chemical reaction involved. In fermentation, glucose is broken down into ethanol (C2H5OH) and carbon dioxide (CO2).
The oxidation of ethanol can be represented by the following reaction:
C2H5OH + 3O2 -> 2CO2 + 3H2O
To calculate delta G for this reaction, we need to know the standard Gibbs free energy change (delta G^o) for the reaction. Once we have the value for delta G^o, we can use it to determine the delta G for the oxidation of ethanol using the equation:
delta G = delta G^o + RTln(Q)
where:
- delta G is the Gibbs free energy change of the reaction under the specific conditions
- delta G^o is the standard Gibbs free energy change
- R is the gas constant (8.314 J/(mol·K))
- T is the temperature in Kelvin
- Q is the reaction quotient
Since you want the answer in kJ/g, we can divide the values by the molar mass of ethanol (46.07 g/mol) to get the delta G per gram of ethanol.
Now, let's calculate the delta G for the oxidation of ethanol (C2H5OH):
1. Calculate the delta G^o for the reaction using standard Gibbs free energy of formation values:
- Delta G^o for C2H5OH = -277.69 kJ/mol
- Delta G^o for CO2 = -394.36 kJ/mol
- Delta G^o for H2O = -285.83 kJ/mol
Delta G^o = (2 * Delta G^o for CO2) + (3 * Delta G^o for H2O) - (Delta G^o for C2H5OH)
= (2 * -394.36 kJ/mol) + (3 * -285.83 kJ/mol) - (-277.69 kJ/mol)
= -788.72 kJ/mol + -857.49 kJ/mol + 277.69 kJ/mol
= -1368.52 kJ/mol
2. Calculate the value of Q, the reaction quotient. Since we are dealing with the oxidation of ethanol, the concentration or pressure terms will not be required as ethanol and its products are in different phases (solid and gas).
Q = 1, as there is only one mole of ethanol present.
3. Convert the temperature to Kelvin. Let's assume the temperature is 298 K.
4. Now, we can substitute the values into the formula:
delta G = delta G^o + RTln(Q)
delta G = -1368.52 kJ/mol + (8.314 J/(mol·K) * 298 K * ln(1))
delta G = -1368.52 kJ/mol + (8.314 J/(mol·K) * 298 K * 0)
delta G = -1368.52 kJ/mol + 0 kJ/mol
delta G = -1368.52 kJ/mol
5. Finally, divide the delta G value by the molar mass of ethanol (46.07 g/mol) to get the delta G per gram of ethanol:
delta G per gram of ethanol = -1368.52 kJ/mol / 46.07 g/mol
delta G per gram of ethanol ≈ -29.74 kJ/g
Therefore, the delta G for the oxidation of ethanol from fermentation is approximately -29.74 kJ/g.