Textbook Fundamentals G #13

[Eileen Quach Dis 2A]

Could someone explain how to solve #13 for Fundamentals G of the textbook? Thanks!

[Mary Gallo 1G]

To solve this problem you are going to use formula: M1V1=M2V2.
Your M1 is 0.20M and your V1 is 1.0L (as given in problem).
Since 3.0L of water is added, your V2 will be 4.0L (1.0L+3.0L).
Now you can solve for the final molarity value.

To convert the molarity into moles you use the formula: M=mol/L
This can be rearranged as: mol=M*L

Then plug in the final molarity value you found to start and multiply by 0.1L (given as 100mL in the problem but we want to be in units of liters)

This will give you the moles of NH4NO3 and you can use mole to mole ratios to find the moles of just nitrogen:
moles of NH4NO3 x (2 mol N)/(1 mol NH4NO3) = moles of nitrogen

The mole to mole ratio is 2:1 because there are 2 moles of nitrogen in NH4NO3

Please let me know if I can clarify anything, hope this helps!