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Homework 7A.1

Posted: Mon Mar 09, 2020 11:05 pm
by Brandi 2C
Hii I was wondering if I could get some help with parts (b) and (c) for this homework question?
Complete the following statements relating to the production of ammonia by the Haber process, for which the overall reaction is N2(g) + 3 H2(g) --> 2 NH3(g). (a) The rate of consumption of N2 is ______________ times the rate of consumption of H2. (b) The rate of formation of NH3 is ________________ times the rate of consumption of H2. (c) The rate of formation of NH3 is ________________ times the rate of consumption of N2.

For (b) I thought that it would be 3/2 since theres 3 H2 and 2 NH3 but according to a past thread (from 2018) it is actually 2/3. And for (c) I thought it would be 1/2 since only 1 N2 is needed to make 2 NH3 but it is actually just 2. Can someone please explain to me why/how I mixed up the relationships' numerators/denominators? Thank you!

Re: Homework 7A.1

Posted: Mon Mar 09, 2020 11:29 pm
by 805312064
for b, since only 2 moles of nh3 are formed for every 3 moles of h2, nh3 is formed 2/3 times as fast as h2 is used. the same is true for n2 and nh3.

Re: Homework 7A.1

Posted: Tue Mar 10, 2020 10:29 pm
by Charlene Datu 2E
Your answer is dependent on the molecule being altered in order to reach the rate of the second molecule. For example in b, the NH3 is being altered in order to derive the rate of H2. In that case, there are 2NH3 formed for every 3H2 consumed. Therefore the rate of NH3 formation is 2/3 the rate of H2 consumption.

Re: Homework 7A.1

Posted: Tue Mar 10, 2020 10:34 pm
by Luyan Zhang - 2D
You should rearrange the equation so that rate of NH3 formed is in term of rate of consumption of H2.

Re: Homework 7A.1

Posted: Wed Mar 11, 2020 10:40 pm
by Morgan Carrington 2H
It looks like you had the right, but just had the answers flipped around. For part b, it is comparing the rate of NH3 to H2. So when doing this, you would have the balanced number of mols of H2 as the denominator and the number of mols of NH3 on the top. Same idea goes for part C, but now you are looking at the concentration of NH3 relative to N2 so you would have to make sure to put N2 as the denominator.