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 R present. If the concentration of chemical R 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?
Choose the most appropriate option.
A) 100% decrease  B) 50% decrease  C) 40% decrease  D) 40% increase  E) 50% increase
Let A and R be the concentratrations of the individual chemicals.   Rate of chemical reaction = A^2/R   Since new R is increased by 100%   Rate = A^2/(2R)   For the rate to be constant, new value of A should be square root(2)   So new value of A = 1.414A   That means A is increased by 41.4%   Nearest solution is 40% increase
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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 R present. If the concentration of chemical R 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?