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Nare Arakelian Dis 3E
Posts: 58
Joined: Thu Jul 11, 2019 12:16 am


Postby Nare Arakelian Dis 3E » Mon Oct 07, 2019 9:21 pm

To prepare a fertilizer solution, a florist dilutes 1.0 L of
0.20 m NH4NO3(aq) by adding 3.0 L of water. The florist then adds
100. mL of the diluted solution to each plant. How many moles of
nitrogen atoms will each plant receive? Solve this exercise without
using a calculator.

I used M1V1=M2V2 to find the concentration of NH4NO3 (0.05 M), but I am struggling with finding the moles of nitrogen atoms. I know the volume is 0.100 L, but I am not sure what concentration to use. Can someone explain?

Harry Zhang 1B
Posts: 101
Joined: Sat Sep 14, 2019 12:16 am

Re: G13

Postby Harry Zhang 1B » Mon Oct 07, 2019 9:30 pm

One thing to keep in mind is that the moles of solute never change. So to find out how many moles of solute are in the solution, we multiply 0.2 M by 1.0, which indicates that there are 0.2 moles of ammonium nitrate molecules. In this case, you final volume would be 1 L + 3 L, Which equals to 4 L. Divide 0.2 moles by 4 L= 0.05 M. Up to this point, your calculation is correct and you were wondering what concentration to use. In this case, we will use 0.05 M since it's the diluted concentration(adding water to a solution makes it diluted). Finally, we multiply 0.05 mole/L by 0.1 L and you will have your moles of nitrogen atoms, which is 0.005 moles.

Ali Polansky 1A
Posts: 15
Joined: Fri Aug 09, 2019 12:15 am
Been upvoted: 1 time

Re: G13

Postby Ali Polansky 1A » Mon Oct 07, 2019 10:55 pm

0.005 moles is the number of moles each plant receives of NH4NO3. To find moles of N atoms each plant will receive you take 0.005 moles and multiply by the molar ratio (2 moles of N atoms: 1 mole of NH4NO3) so each plant receives 1 x 10^-2 moles of nitrogen atoms.

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