- #1
Lithium Hydroxide 0.602mole Calculation
- Thread starter chawki
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Discussion Overview
The discussion revolves around the calculation of moles in a chemical reaction involving lithium nitride and water, specifically focusing on the formation of lithium hydroxide and ammonia. Participants explore stoichiometry, limiting reagents, and the implications of reactant quantities in the context of a homework problem.
Discussion Character
- Homework-related
- Mathematical reasoning
- Debate/contested
Main Points Raised
- One participant calculates the number of moles of lithium hydroxide produced from lithium nitride and water, arriving at 0.602 moles.
- Another participant challenges the relevance of the 0.602 mole figure, suggesting that 14.4g is a more appropriate answer.
- There is confusion regarding the parts of the homework question, with one participant mistakenly interpreting the question due to its presentation as an image.
- Participants discuss how to approach the calculation of ammonia produced from given moles of lithium nitride and water, with references to limiting reagents.
- Several participants attempt to clarify the concept of limiting reagents and how to determine which reactant limits the product formation.
- One participant expresses uncertainty about the calculations and understanding of limiting reagents, leading to further questions and examples being provided.
- There is a discussion about the stoichiometric relationships in the reaction, with participants calculating potential yields based on different reactant amounts.
- One participant asserts that water is the limiting reagent, while another questions the reasoning behind this conclusion, leading to further clarification attempts.
Areas of Agreement / Disagreement
Participants do not reach a consensus on the calculations or the interpretation of limiting reagents. Multiple competing views and uncertainties remain throughout the discussion.
Contextual Notes
Some participants express confusion about the stoichiometric calculations and the concept of limiting reagents, indicating a need for clearer understanding of the underlying principles. There are unresolved mathematical steps and assumptions regarding the quantities of reactants involved.
- #2
Borek
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0.602 mole is not an answer to any of the questions asked. 14.4g is much better.
- #3
chawki
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But in part a, they asked to find number of moles.
- #4
Borek
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Sorry, my mistake, somehow I read they just asked about mass in the first part of the question, and moles in the second. That's partially because you entered question as an image - I had to switch between the answer and the question, it doesn't help.
- #5
chawki
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Ok, I'm sorry too for putting the question on image.
If the number of moles in part a is correct, please give me a hint how should approach part b, where they ask how many moles of ammonia can be formed if 2.5moles of lithium nitride is mixed with 4.5moles of water
- #6
Borek
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- #7
chawki
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n= (18.01*7)/(54+34.83)
n=1.419 mole.
- #8
Borek
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No. Forget about masses, calculate just number of moles.
- #9
chawki
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n=7/4 mole ?
- #10
Borek
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Where did you got 7 and 4 from?
Take a look at the reaction equation.
http://www.chembuddy.com/?left=balancing-stoichiometry&right=stoichiometric-calculations
How many moles of LiOH can be produced from 1 mole of lithium nitride? From 2.5 mole of nitride?
How many moles of LiOH can be produced from 1 mole of water? From 4.5 mole of water?
- #11
chawki
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How many moles of LiOH can be produced from 1 mole of lithium nitride? From 2.5 mole of nitride?
How many moles of LiOH can be produced from 1 mole of water? From 4.5 mole of water?[/QUOTE]
From 2.5mole of lithium nitride, we have 2.5*3mole of LiOH
From 4.5mole of water , we have 4.5 mole of LiOH
- #12
Borek
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chawki said:
So, which one is a limiting reagent and what is the final answer?
- #13
chawki
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I really have no clue...
- #14
Borek
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Have you read limiting reagent page that I linked to several posts earlier?
- #15
chawki
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yes but i didn't understand it...sorry
- #16
Borek
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H2 + Cl2 -> 2HCl
You mix 1 mole of hydrogen and 1000000 moles of chlorine - how many moles of HCl would you get?
You mix 1 mole of hydrogen and 1000000 moles of chlorine - how many moles of HCl would you get?
- #17
chawki
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Borek said:
Please tell me
- #18
Borek
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Take a look at the reaction equation and stoichiometric coefficients.
How many moles of HCl can be produced from 1 mole of hydrogen? How many moles of Cl2 are needed for that? Do we have that much chlorine?
How many moles of HCl can be produced from 1000000 moles of chlorine? How many moles of H2 are needed for that? Do we have that much hydrogen?
How many moles of HCl can be produced from 1 mole of hydrogen? How many moles of Cl2 are needed for that? Do we have that much chlorine?
How many moles of HCl can be produced from 1000000 moles of chlorine? How many moles of H2 are needed for that? Do we have that much hydrogen?
- #19
chawki
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Borek said:
we can get 2 moles of HCl from 1 mole of hydrogen and 1 mole of Cl2
i used to have a method like '' x-number of moles'' but i forgot it :(
- #20
chawki
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so how many moles of HCl we get for mixing 1 mole of hydrogen and 1000000 moles of chlorine 
- #21
Borek
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No, you will not get the answer, you have to work it out. Try to answer all questions I have asked, it should become obvious what the final answer is. Answering 1 question out of 4 and hoping for a miracle won't get you far.
- #22
symbolipoint
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The amount of product HCl will depend on the limiting reagent.
- #23
chawki
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wanna give me an example ?
- #24
QuarkCharmer
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[PLAIN]http://www.chem.tamu.edu/class/majors/tutorialnotefiles/cars.gif
In this example, you only need 32 tires to put those 8 car bodies to good use. Since there is excess tires after the reaction (cars getting the tires installed), the bodies are what limit the reaction.Sometimes it is hard to tell which of the reactants will limit the product. If that is the case, you need to use one given reactant and express it in terms of moles of the other reactant. If that is greater than the second given reactant, then you "need" more of that second reactant, and so that is the limited reactant.The ratio of H to Cl in your balanced equation is 1/1...
http://www.khanacademy.org/video/stoichiometry--limiting-reagent?playlist=Chemistry
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- #25
chawki
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Borek said:
limiting reagent is H2O because the ratio Li3N/H2O = 1/3 =2.5/(3*2.5) = 2.5/7.5
we have too much H2O than we need
- #26
chawki
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the equation will be:
Li3N + 3 H2O ----> 3 LiOH + NH3
we multiply by 1.5 in order to get 4.5 moles of the limiting reagent.
1.5 Li3N + 4.5 H2O ----> 4.5 LiOH + 1.5 NH3
so we will get 1.5 mol of NH3
i hope I'm right
Li3N + 3 H2O ----> 3 LiOH + NH3
we multiply by 1.5 in order to get 4.5 moles of the limiting reagent.
1.5 Li3N + 4.5 H2O ----> 4.5 LiOH + 1.5 NH3
so we will get 1.5 mol of NH3
i hope I'm right
- #27
Borek
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chawki said:
If water is a limiting reagent, we can't have too much of it.
chawki said:
Surprisingly, this is a correct answer. As I am not able to follow your line of thinking I am not convinced it is not accidental.
- #28
chawki
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Borek said:
ok well, isn't water the limiting reagent ?
I just watched that video and learned from it.
- #29
Borek
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Water IS a limiting reagent, but it means there is not TOO MUCH of water, but NOT ENOUGH.
- #30
chawki
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ahhh ok, i will try to understand that, and thank you again :)
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