Choosing the Best Fertilizer: Ammonium Nitrate vs. Liquid Ammonia

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Discussion Overview

The discussion revolves around comparing liquid ammonia and ammonium nitrate as fertilizers, specifically focusing on their nitrogen content by mass. Participants explore the calculations and reasoning behind determining which fertilizer is superior based on nitrogen percentage.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant expresses confusion about calculating the nitrogen content in ammonium nitrate and liquid ammonia, providing initial percentages for ammonium nitrate.
  • Another participant suggests using molar masses to calculate the nitrogen percentages and emphasizes the importance of showing work for clarity.
  • A third participant mentions that calculations may not be necessary if the relative masses of hydrogen and nitrogen are known.
  • One participant proposes calculating the percentage of nitrogen based on a mole basis for both compounds.
  • A later reply confirms the calculations for the molar masses of both compounds and concludes that liquid ammonia has a higher percentage of nitrogen, suggesting it is the better fertilizer.
  • Another participant agrees with the conclusion but notes that one could have estimated the answer by observing the formulas without detailed calculations.

Areas of Agreement / Disagreement

There is some agreement that liquid ammonia has a higher percentage of nitrogen, but the discussion includes differing opinions on the necessity and method of calculations. Some participants emphasize the importance of showing work, while others suggest estimation could suffice.

Contextual Notes

Participants have not fully resolved the best approach for determining fertilizer effectiveness, as there are varying opinions on calculation methods and the importance of detailed work versus estimation.

Lindy12
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I'm having trouble with a question and I'm almost too embarassed to ask! I;ve spent the last couple hours trying to figure it out though and am getting nowhere fast.

Liquid ammonia and ammonium nitrate, based on percentage of nitrogen by mass, which of these 2 would be the better fertilizer.

Ammonium Nitrate - NH4No3
Liquid Ammonia - NH3 ??

Where do I start? I did something and got ammonium nitrate as having 35% N, 5% H and 60% O.
 
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Lindy12 said:
I'm having trouble with a question and I'm almost too embarassed to ask! I;ve spent the last couple hours trying to figure it out though and am getting nowhere fast.

Liquid ammonia and ammonium nitrate, based on percentage of nitrogen by mass, which of these 2 would be the better fertilizer.

Ammonium Nitrate - NH4No3
Liquid Ammonia - NH3 ??

Where do I start? I did something and got ammonium nitrate as having 35% N, 5% H and 60% O.
This one is now going to use percentage masses (as you know) which is what I think would have been better in the other question you did. So now you are going to learn it.

You have the molecular formulae and you can, therefore, work out the molar masses of each. You then need to write out each of the elements in the compound separately and find there relative atomic mass (which you must know to have found the molar mass). Simple apply the way you work out a percentage to each of the elements and you can find which will have the most.

This may have been what you did but you have not put any workings down so I have assumed you almost guessed the answers. A word of caution: make sure you write what you have done, no matter how silly, so we can see where you are going right/wrong and can help you to proceed.

The Bob (2004 ©)

P.S.
Lindy12 said:
Ammonium Nitrate - NH4No3
I know you may say this is really small but it is important.

You either have to change the N in No3 to a M (for molybdenum) or you need to make the o in No3 a large, capital O so it represents oxygen i.e. NH4NO3.
 
Last edited:
If you're going by mass, you shouldn't have to do any calculations (Assuming you know what the mass of hydrogen relative to nitrogen is)
 
Well start by observing that

total~mass~of~nitrogen~in~the~molecule/total~mass~of~molecule is the percentage, you can multiply by 100, but it isn't necessary.

Start by calculating everything in terms of a mole basis...say you have one mole of each compound and go from there. Show us what you can do.
 
The Bob said:
I know you may say this is really small but it is important.

You either have to change the N in No3 to a M (for molybdenum) or you need to make the o in No3 a large, capital O so it represents oxygen i.e. NH4NO3.
Not small at all! Thank you for pointing that out :)
 
So...(is this correct?)

Molar Mass of Ammonia (liquid): NH3 – 14.0 + (1.0*3) = 17 Amount of Nitrate: 14/17 (82%)
Molar Mass of Ammonium Nitrate: NH4NO3 14.0+(1.0*4)+14.0+(16.0*3): =80 Amount of Nitrate: 28/80 (35%)

Liquid Ammonia has a higher percentage of nitrate and so would be the better fertilizer.
 
Your answer seems to be correct however, you could have easily deduced the answer simply by observing the formula, and making a educated estimation.
 
Lindy12 said:
Liquid Ammonia has a higher percentage of nitrate and so would be the better fertilizer.

...higher percentage of nitrogen...

Chemical calculators at
 

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