Respuesta :
In winemaking, the sugars in grapes undergo fermentation by yeast to yield CH₃CH₂OH and CO₂. During cellular respiration (combustion), sugar and ethanol yield water vapor and CO₂.
a) ΔH rxn (fermentation) = -2816 kJ/mol
ΔH rxn (respiration) = -1409,2kJ/mol
b) CH₃CH₂OH(l) + 3O₂(g) → 2CO₂(g) + 3H₂O(l)
a) The fermentation of sugar is given as follows:
C₆H₁₂O₆ (s) + 6O₂ (g) → 6O₂ (g) + 6H₂O (l)
ΔHrxn = ΔHformation (products) - ΔHformation (reactants
[tex]=(6 mol* - 393.5 kJ/mol) + (6mol* -285.8kJ/mol)- (1mol *-1260kJ/mol+6mol*0 )[/tex]
= -2816 kJ/mol
a) The heat of combustion of ethanol is given as follows:
C₂H₅OH (l) + 3O₂ (g) → 3H₂O(g) + 2CO₂(g)
Let's assume that 1 mole of ethanol is burnt. The heat of reaction, ΔHrxn is given by:
ΔHrxn = ΔHformation (products) - ΔHformation (reactants)
[tex]= (2mol*-393kJ/mol)+ (3mol*-285.8kJ/mol)- [(1mol * -235kJ/mol)+(3mol* 0,0000kJ)][/tex]
[tex]= -1644-(-235.2)\\= -1409.2kJ/mol[/tex]
The exothermic reaction of combustion is indicated by the negative sign.
b)The combustion reaction for ethanol:
C₂H₅OH (l) + 3O₂ (g) → 3H₂O(g) + 2CO₂(g)
It is evident that the combustion of sugar produces more heat than burning ethanol.
To know more about combustion reaction refer to: https://brainly.com/question/12172040
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The complete question is:
Be sure to answer all parts. In winemaking, the sugars in grapes undergo fermentation by yeast to yield CH3CH2OH (ethanol) and CO2. During cellular respiration, sugar and ethanol are "burned" to water vapor and CO2. (a) Using C6H12O6 for sugar, calculate ΔH o rxn of fermentation and of respiration (combustion). Fermentation = kJ Respiration = kJ (b) Write a combustion reaction for ethanol. Include the physical states of each reactant and product.
