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decrease the pressure. On the other hand, the rest of the equations would end up having an equal<br />
number of molecules on each side, causing there to be no shift whether pressure is increased or<br />
decreased.<br />
Question 12 Explanation:<br />
Looking at the equation 4HCl(g) + O2(g) ⇄ 2H2O(l) + 2Cl2(g) + 113 kJ, increasing the systems<br />
pressure will direct it to shift to the right. If the table to the right is considered, it states that an<br />
increase of pressure in a system will shift towards fewer molecules of gas. This is based off Le<br />
Chatelier’s principle, which is used to predict the effect of a change in conditions on a chemical<br />
equilibrium. Therefore, Le Chatelier’s principle demonstrates that considering that equation,<br />
increasing the system’s pressure will cause it to shift to the right of the container it is being held in.<br />
Question 13 Explanation:<br />
The answer is C because The chemical reaction NO2(g) + CO(g) ⇄ NO(g) + CO2(g) is<br />
conducted in a closed flask. To shift this reaction to the left of the flask, the amount of NO<br />
concentration should be increased. Le Chatelier’s principle can be used to predict the effect of a<br />
change in conditions on a chemical equilibrium. A more detailed part of his principle is that increasing<br />
the concentration of a substance will move it away from the substance, and a decrease in<br />
concentration will move it towards the substance. Therefore, to move the concentration away from<br />
where it is and to the left of the flask, then the concentration should be increased for it to do so.<br />
Question 14 Explanation:<br />
The answer is A because, Considering the equation NH4Cl(s) +<br />
heat ⇄ NH3(g) + HCl(g), a decrease in total pressure will allow the<br />
substance to be moved to the right and form more products. Le<br />
Chatelier’s principle can be used to predict the effect of a change in<br />
conditions on a chemical equilibrium. According to this principle,<br />
decreasing the amount of pressure in a system will allow the<br />
substance to move towards more molecules and produce more<br />
products. Thus, decreasing the total pressure will allow the substance<br />
of the equation to be moved to the right and form more products,<br />
according to Le Chatelier’s principle.<br />
Question 15 Explanation: The answer is D because in a sealed<br />
bottle that is half full of water, equilibrium will be attained when<br />
water molecules evaporate and condense at equal rates.<br />
According to the textbook, equilibrium is a state in which<br />
opposing forces or influences are balanced. Thus, if a sealed<br />
bottle is half full of water, to balance out the evaporation of water,<br />
water also has to condense. This has to happen at an equal rate<br />
in order for its equilibrium to remain. If one was to happen at a<br />
different rate compared to the other, then it would be unbalanced<br />
and there would be no equilibrium within the system. Therefore,<br />
water molecules in the system must evaporate and condense at<br />
equal rates in order for there to be balance.<br />
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