Intro To Chemistry

Question

1. You have 3 moles of C₂H₆O.
2. How many moles of carbon are in 3 mol of C₂H₆O?  moles
3. How many moles of hydrogen are in 3 mol of C₂H₆O?  moles
4. How many moles of oxygen are in 3 mol of C₂H₆O?  moles

Answer 1

Question:  You have 3 moles of C₂H₆O.

1. How many moles of carbon are in 3 mol of C₂H₆O?  
2. How many moles of hydrogen are in 3 mol of C₂H₆O?  
3. How many moles of oxygen are in 3 mol of C₂H₆O?  

You must use the mole to mole ratio to solve this problem. In 1 mole of C₂H₆O there are 2 moles C, 6 moles H and 1 mol O.

First question: multiply 3 moles by the mole ratio (2 mol C for every 1 mol C₂H₆O

3 mol C₂H₆O * (2 mol C/1 mol C₂H₆O) = 6 mol C

Follow the same steps for the others. Make sure to cancel out the moles of C₂H₆O by putting it on the bottom of your conversion factor

Answer 2

This is pretty easy. 

All you have to do is multiply the number of moles of the compound by the subscripts of each element in the compound. In this case, there are 3 x 2 = 6 moles of carbon. You should be able to figure out the rest.