Question

3. The alcohol in "gasohol" burns according to the following equation. C2H6O + 3 O2 --------> 2 CO2 + 3 H2O (a) If 25 moles of ethyl alcohol burns this way, how many moles of oxygen are needed? (b) If 30 moles of oxygen is consumed by this reaction, how many moles of alcohol are used up? How many moles of carbon dioxide are formed? (c) In one test, 23 moles of carbon dioxide was produced by this reaction. How many moles of oxygen were consumed? (d) In another test, 41 moles of water is collected from this reaction. How many moles of alcohol had been consumed?

Answer 1

For all question, all you need to use is the mole-mole ratio. 

a) 25 moles C2H6O (3 moles O2/ 1 mol C2H6O)= 75 moles O2 

b) 30 moles O2 (1 moles C2H6O/ 3 moles O2)= 10 moles C2H6O

c) 23 moles CO2 (3 moles O2/ 2 moles CO2) = 34.5 moles O2

d)  41 moles H2O ( 1 moles C2H6O/ 3 moles H2O= 13.7 moles C2H6O