Chemistry Please help thank you so much!?

2020-07-05 8:44 am
Consider the following reaction: 2 Mg+CO2<-->2 MgO+C . A laboratory technician wants to increase the amount of MgO produced. Which of the following is the best way to accomplish this?

Add a catalyst.


Increase the amount of carbon.


Decrease the amount of Mg.

Decrease the amount of carbon.

回答 (2)

2020-07-05 11:16 am
The answer: None of the four options

Explanation:
The first option is false. Adding a catalyst can only increase the rates of forward and backward reactions but does not affect the position of equilibrium.

Consider the equation of the reaction:
2 Mg(s) + CO₂(g) ⇌ 2 MgO(s) + C(s)
This is a heterogeneous equilibrium. The increase of decrease the amount of any solid component (Mg, MgO or C) does not affect the position of equilibrium. Hence, the second, third and fourth options are false.
2020-07-05 9:36 am
via Le Chatelier's principle.. if you add stress to a system, it will react to remove the stress
example.. A + B <---> C + Dif you
.. add A or B, the reaction will shift RIGHT to consume the extra A or B
.. add C or D, the reaction will shift LEFT to consume the extra C or D
.. remove A or B, the reaction will shift LEFT to produce more A or B
.. remove C or D, the reaction will shift RIGHT to produce more C or D

********
think of it as a balance.. like this

let's say we have this reaction
... 1A <---> 2 B

and let's initially, we have 100 A and 100 B present in a 1:1 ratio

if we add 15 more B our ratio is not at equilibrium anymore (1:1 for this case).  It's 115/100  so the reaction shifts left to consume some of the extra B to make the ratio 1:1 again. 

in tabular form.. 

if we add 15 B
.. .. .. .. .. .. ... A.. .. .. . . .B.. .. .  .A:B ratio
.. initially.. ... 100.. . .. .100. . .. 1:1
.. .we add.. .. .... .. .. . .+15.. .. .115:100 ≠ 1:1
.. rxn shift..  ...+5.. ... .. -10.. .. . .. .. .. .. .. . . .the rxn shifts LEFT to consume 10 B
.. . final.. ... ..105.. .. . ..105.. . .1:1

if we remove 15 B
.. .. .. .. .. .. ... A.. .. .. . . .B.. .. . .A:B ratio
.. initially.. ... 100.. . .. .100. . .. 1:1
.. .we add.. .. .... .. .. . .-15.. .. .115:100 ≠ 1:1
.. rxn shift.. ...-5.. ... .. +10.. .. . .. .. .. .. .. . . .the rxn shifts Right to produce more B
.. . final.. ... .. 95.. .. . .. 95.. . .1:1


 


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