FINISHED_Final_Notebook_Jones
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B. decreasing the concentration of C 6<br />
H6<br />
C. increasing the concentration of HBr<br />
D. decreasing the temperature<br />
Explanation: ‘A’ would be the answer because the greater the concentration of one of the reactants,<br />
the higher the possibility of collision. The other answers are wrong either because they have the<br />
opposite effect, or deal with the product, not the reactants. Decreasing the concentration of C 6<br />
H6<br />
would simply decrease the reaction rate because there is less availability of reactants to make<br />
products. Increasing the concentration of HBr would have absolutely no effect on the reaction rate of<br />
C6H6<br />
+ Br2 because it is a product, not a reactant. Lastly, decreasing the temperature would have the<br />
opposite of the desired effect, because the lower the kinetic energy of the reactants, the slower they<br />
move, thus the less the reactants ability to collide and make product.<br />
2CO + O2<br />
→ 2CO2<br />
6. If the above reaction takes place inside a sealed reaction chamber, then which of these procedures<br />
will cause a decrease in the rate of reaction?<br />
A. raising the temperature of the reaction chamber<br />
B. increasing the volume inside the reaction chamber<br />
C. removing the CO2 as it is formed<br />
D. adding more CO to the reaction chamber<br />
Explanation: Increasing the volume would decrease the rate of reaction because the greater the<br />
space available for particles to occupy, the less the concentration, and thus there is a less likely<br />
chance of collision, which subsequently results in a decrease in the rate of reaction. That is why ‘B’ is<br />
the answer. Raising the temperature of the reaction chamber would increase the rate of reaction<br />
because if the temperature of the reactants is increased, that means there is a greater kinetic energy,<br />
which means greater chance for collision, which means a higher reaction rate (which is the opposite<br />
of the desired effect). Removing the CO 2<br />
as it was formed would just leave more room for the product<br />
of the reactants, and although it means the reactants can continue to make product, it does not mean<br />
the reaction rate will increase.<br />
7. A catalyst can speed up the rate of a given chemical reaction by<br />
A. increasing the equilibrium constant in favor of products.<br />
B. lowering the activation energy required for the reaction to occur.<br />
C. raising the temperature at which the reaction occurs.<br />
D. increasing the pressure of reactants, thus favoring products.<br />
Explanation: Catalysts are substances that decrease the activation energy of a reaction, and as a<br />
result increase reaction rate. This clearly demonstrates why ‘B’ is the answer. “Increasing the<br />
equilibrium constant in favor in of products” is not the answer because an equilibrium constant is a<br />
quotient, or ratio, of the reaction when it hits equilibrium. It is really a measurement of the ratio of<br />
elements involved in equilibrium, rather than anything that actually affects it. “Raising the temperature<br />
at which the reaction occurs” implies raising the activation energy, which has the exact opposite effect<br />
of a catalyst, and accomplishes the complete opposite task. “Increasing the pressure of reactants,<br />
thus favoring products” is not what a catalyst does, simple as that. Catalysts merely lower the<br />
activation energy of a reaction, they do not affect, whatsoever, the conditions under which the<br />
reaction is subjected to.<br />
8. Which reaction diagram shows the effect of using the appropriate catalyst in a chemical reaction?<br />
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