Qrtr 4 final

each. With this in tow, a reactant takes less time to build up enough energy to convert. It comes to
the same end as if it was just the reactant without the catalysts, since catalysts don’t react with the
substances. It just happens faster.
8 Which reaction diagram shows the effect of using the appropriate catalyst in a chemical reaction?
A
C
B
D
Similar to question 1 , Catalysts allow a reaction to proceed along a lower energy path. The
graph is actually fairly similar to that of question 1 so i’ll explain it the same way. Before the catalyst,
the reaction proceeds like normal with a normal activation energy. However, with the catalyst, the
activation energy is brought way down. That’s why you can see in the graph where “After Catalyst” is
pointing, the point of reaction is at a lower energy than the original reaction.
9 H​ 2​
O​ 2,​
hydrogen peroxide, naturally breaks down into H​ 2​
O and O​ 2​
over time. MnO​ 2​
, manganese
dioxide, can be used to lower the energy of activation needed for this reaction to take place and, thus,
increase the rate of reaction. What type of substance is MnO​ 2​
?
A a catalyst
B an enhancer
C an inhibitor
D a reactant
MnO2 would be a catalyst because it facilitates the rate of reaction in this situation. It lowers
the activation rate for the reaction and so it would make the whole process faster. When MnO2 acts
as a catalyst and lowers the activation energy, it quickens the rate of reaction rate because the
reactants no longer have to reach the same high (higher) level of energy that they used to. Once
MnO2 lowers the activation energy, the reactants need less time to build up the energy to form the
reaction and in the end, it takes less time.
10 When a reaction is at equilibrium and more reactant is added, which of the following changes is
the immediate result?
A The reverse reaction rate remains the same.
B The forward reaction rate increases​.
C The reverse reaction rate decreases.
D The forward reaction rate remains the same.
The forward reaction rate of the reaction would increase when more reactant is added. This is
because equilibrium is the state where the same amount of reactant is being converted as there is
product being decomposed. The rate of the reactant reacting slows down over time because less
reactant is available to react (that was difficult to word). If you added more reactant to the system, the
forward reaction rate (ie the original reaction) would increase because more “”stuff”” is available to
react. If it runs out, it will slow down, but adding reactant moves the reaction along.