In winemaking, the sugars in grapes undergo fermentationby yeast to yield CH3CH2OH and CO2. During cellularrespiration, sugar and enthanol are "burned" to water vapor andCO2.
A) Using C6H12O6 for sugar, calculate ÄH of fermentation and of respiration(combustion).
B) Write a combustion reaction for ethanol. Which has ahigher ÄH for combustion per mole of C, sugaror ethanol?
am I right?
-69
-2538.7
ethanol
I need help with B)balancing the equation. Thanks.
Answer this Question•Chemistry - Mark, Saturday, October 24, 2015 at 10:11am
i think it's
C2H6OH(l) + 3O2(g) ---> 2CO2(g) + 3H2O(g)
To calculate ΔH of fermentation and respiration, we need to determine the heat released or absorbed during the reactions. The ΔH represents the change in enthalpy.
A) Fermentation:
The balanced equation for fermentation is:
C6H12O6(aq) → 2CH3CH2OH(aq) + 2CO2(g)
To calculate ΔH of fermentation, we need to use the standard enthalpies of formation (ΔHf) of reactants and products.
The ΔH of fermentation can be calculated using this equation:
ΔH = [2ΔHf(CH3CH2OH) + 2ΔHf(CO2)] - ΔHf(C6H12O6)
B) Combustion of Ethanol:
The balanced equation for combustion of ethanol is:
C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(g)
To balance this equation, start by counting the number of atoms for each element on both sides. It should be balanced in terms of the number of carbon, hydrogen, and oxygen atoms.
C: 2 on the left, 2(1) + 2(2) = 6 on the right
H: 6 on the left, 6 on the right
O: 1 on the left, 2(2) + 3(1) = 8 on the right
The balanced equation is:
C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(g)
Regarding the ΔH of combustion, you are correct. The ΔH of combustion for ethanol is -2538.7 kJ/mol.
Comparing the ΔH of combustion per mole of carbon, sugar (C6H12O6) has more carbon atoms in its formula than ethanol (C2H5OH). Therefore, sugar would have a higher ΔH for combustion per mole of carbon than ethanol.
I hope this helps! Let me know if you have any further questions.