calculating energy (1 Viewer)

[AnAn]

1) Given that the production of one mole of ammonia releases 46KJ of energy, determine the maximum amount of energy that could be released when 2.5 moles of nitrogen gas and 6 moles of hydrogen gas are hearted together.
* anyone can teach me how to do this Q? what should i do first?

2)explain why a company would be concerned by either low reacton rates of low product yields

 

[TheKing]

uh simple moles..... prelim stuff
N2 + 3H2 -> 2NH3
that means that for every 2moles of ammonia you need 1 mole of nitrogen gas and 3moles of hydrogen gas.
seeing as theres only 6moles of hydrogen heated. you end up with 4 moles of ammonia.
and so energy released is 46kJ x 4
i think i' right...

 

[TheKing]

low production yeilds refer to % of NH3
and
low reaction rates refer to the speed at which ammonia is produced.

so basically we're looking at like cost and time... theres more but its all in your textbook or class notes...
read through it first

 

[TheKing]

so i'm guessing i'm correct? can someone please confirm it so that i that i'm a little more confident...

 

[AnAn]

you r right....you r "TheKing"

 

[xiao1985]

uhm, hard to say... because the reaction is in equilibrium and when heated the equilibrium constant decreases due to le chatielier principle... so hard to say how many heat is produced...

 

[mr EaZy]

Is equilibrium constant changed by temperature only?
I heard it remains constant when pressure, and moles of substances are added?

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I agree with King . Forget the equilibrium stuff...,, what is limiting reagent by the way??

 

[snoopwogg]

Mr EaZy.. What school do you go to? Would your name be attia by any chance??

 

[TheKing]

alright....
yes the equilibrium K remains constant until temp. changes

i think that it would be safe to presume that we do not have to consider the ammonia changing back into n2 and h2

 

[Xayma]

Originally posted by mr EaZy
I agree with King . Forget the equilibrium stuff...,, what is limiting reagent by the way??

The limiting reagent is the one that controls how much of the reaction can take place (ie it is the one that runs out first)

 

[xiao1985]

ok, maximum heat liberated...... so presumably, we do assume the reaction go to completion...

 

[TheKing]

u just make things too complicated....
i mean his asking about mole ratios stuff
don't think he need to be confused with equilibriums and crap

 

[xiao1985]

i agree that in this question the question, which refer to the maximum amount of energy that could be released from the given reactants, you can assume the reaction go to completion... another hint to look for is that they didn't give the sufficient information if equilibrium is taken into consideration...

whereas, if sufficient data is given, then equilibrium needs to be considered when calculating the amount of energy that is released...