GCHEM question ADA #63

[whale86]

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I've seen this question on several practice exams so if anyone can help explain how to solve such problems, it would be great 🙂

The equation for the Harber process for production of ammonia is N2 + 3H2 --> 2NH3. What is the maximum number of NH3 which can be produced on reaction of a mixture containing 5 moles of N2 and 6 moles of H2?

1- 9
2- 10
3- 6
4- 2
5- 4


Thanks! 🙂

 

[CANgnome]

well, assuming haber is irreversible, which it is not,

you need 3 moles of H2 per mole of N2, so H2 is limiting. you have 6 moles of H2, so x2, maximum is 4 moles of NH3

5-4??

 

[herkulease]

this is a simple limiting reagent question.

you need 3 moles of H2 to make 2 moles of NH3.

You only have 6 moles of H2 and more than enough(excess) moles of N2. So the maximum moles of NH3 you can make is 4.

 

[whale86]

got it! thanks!