Help? (Chemistry)

Question

Wine goes bad soon after opening because the ethanol (CH3CH2OH) in it reacts with oxygen gas (O2) from the air to form water (H2O) and acetic acid (CH3COOH),the main ingredient of vinegar.What mass of ethanol is consumed by the reaction of 1.42 g of oxygen gas?

Round your answer to 3 significant digits.

Answer 1

Hi, Malik,

To begin with, it's VERY important to rewrite the chemistry reaction, and make sure that it is balanced (i.e., the same number of each element on both sides of the reaction arrow). Here's the chemistry reaction itself:

C₂H₆O (ethanol) + O₂ (oxygen gas) -> C₂H₄O₂ (acetic acid) + H₂O (water)

If you count up the C's, H's, and O's, you'll see that this IS a balanced equation where one molecule of ethanol will react with one molecule of oxygen gas to give one molecule of acetic acid plus one molecule of water. Nice!

Next, we have to determine how many moles 1.42 grams of oxygen is as this will be the same number of moles which would be consumed in this reaction. To do this, we use the following equation:

Moles (O₂) = mass O₂/molecular mass of O₂

X = 1.42 grams/32.0 grams/mole

X = 0.0444 moles of O₂

Therefore, 0.0444 moles of ethanol will be consumed by the above reaction. Finally, we need to convert this mole value into its corresponding mass as follows:

Mass (ethanol) = moles (ethanol) X molecular weight (ethanol)

Y = 0.0444 moles (ethanol) X [(2 X 12.0) + (6 X 1.01) + (1 X 16.0)] grams/mole (ethanol)

Y = 0.0444 moles X 46.1 grams/mole

Y = 2.05 grams ethanol (C₂H₆O)

Rounding to three significant figures, 2.05 grams of ethanol would be consumed in this reaction.

'Hope that helps, Malik,

Chris