stiometry help please

Question

In the body, ethanol, , reacts according to the following equation: C2H6O(aq)+3O2(g)ethanol→2CO2(g)+3H2O(l) ethanol

part a: how many grams of O2 are needed to react with 7.45g of ethanol

part b: how many grams of H2O are produced from 7.45 g of ethanol

part c: how many grams of CO2 are produced from 7.45 g of ethanol

Answer 1

In this type of problem, you must first convert the mass from grams to moles. To do this, we need to know the molar mass of each molecule in this reaction. You can determine each of these, but I'll skip that part and list them here (rounded):

Ethanol (C₂H₆O): 46.0 g/mol

O₂: 16.0 g/mol

CO₂: 44.0 g/mol

H₂O: 18 g/mol

The other important information are the coefficients for each reactant and product, which is given in the balanced equation:

(1) C₂H₆O

(3) O₂

(2) CO₂

(3) H₂O

Since each question starts with 7.45 g of ethanol, we can convert that to moles, and use that number of moles for each question. We must divide by the molar mass.

(7.45 g [eth]) / (44.0 g/mol) = 0.162 mol [ethanol]

Now we can set up a proportion for each part. We need the ratio for the two molecules in each question.

Part A:

1 [C₂H₆O] : 3 [O₂]

1 = 3

0.162 mol X mol O₂

Cross multiply to solve for moles of oxygen, and you get:

X = 0.486 mol O₂

To convert this to grams, we must multiply by the molar mass of oxygen:

0.486 mol x 16.0 g/mol = 7.77 g O₂

Therefore, to answer Part A, 7.77 grams of O₂ are needed to needed to react with 7.45g of ethanol.

Try to solve Part B and C on your own, but if you need help with that, please let me know!