The rate of a certain chemical reaction is directly proportional to the square of the concentration of chemical A present and inversely proportional to the concentration of chemical B present. If the concentration of chemical B is increased by 100 percent, which of the following is closest to the percent change in the concentration of chemical A required to keep the reaction rate unchanged?
A. 100% decrease
B. 50% decrease
C. 40% decrease
D. 40% increase
E. 50% increase
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Rate of a certain chemical reaction, R, is directly proportional A²/Bdreamv wrote:The rate of a certain chemical reaction is directly proportional to the square of the concentration of chemical A present and inversely proportional to the concentration of chemical B present. If the concentration of chemical B is increased by 100 percent, which of the following is closest to the percent change in the concentration of chemical A required to keep the reaction rate unchanged?
A. 100% decrease
B. 50% decrease
C. 40% decrease
D. 40% increase
E. 50% increase
When the concentration of chemical B is increased by 100 percent, then concentration of chemical A also increases by, say, a%.
Then, R = A²/B = (aA)²/2B
A²/B = a²A²/2B
1 = a²/2
a² = 2
a = 1.4, which means there is [spoiler]40% increase[/spoiler] in the concentration of chemical A.
The correct answer is D.
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