Constant Ratio

[Stockmoose16]

This problem has been dealt with a few times on this board, but I'm confused with the formula that people come up with...

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 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

From the information in the problem I get:

R= 1/B

or

R = A^2

which means: A^2= 1/B

Everyone who's answered the question says the ratio should be:

R= A^2/B

Where is the formula coming from? The question clearly says that R is equal to the inverse of B, and it's also equal to A^2. So how do we come up with A^2/B.

OA is D

[sudhir3127]

This problem has been dealt with a few times on this board, but I'm confused with the formula that people come up with...

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 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

From the information in the problem I get:

R= 1/B

or

R = A^2

which means: A^2= 1/B

Everyone who's answered the question says the ratio should be:

R= A^2/B

Where is the formula coming from? The question clearly says that R is equal to the inverse of B, and it's also equal to A^2. So how do we come up with A^2/B.

OA is D

we need to understand that , the main chemical ( R ) is a combination of ratios of A and B ...

[logitech]

This problem has been dealt with a few times on this board, but I'm confused with the formula that people come up with...

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 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

From the information in the problem I get:

R= 1/B

or

R = A^2

which means: A^2= 1/B

Everyone who's answered the question says the ratio should be:

R= A^2/B

Where is the formula coming from? The question clearly says that R is equal to the inverse of B, and it's also equal to A^2. So how do we come up with A^2/B.

OA is D

Well R here is a function and its value changes with different A and B.

R(A,B) = Rate

In math you can express this as:

R = k (constant ) A^2/B

If you look at the equation, if everything remains constant and if you double the B, R will be R/2

and in a same way, if every thing else remains constant and you double the A, R will be 4R

In math you can define this :

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 B present

you can actually add new rules like R is also inversely proportional to the square of the concentration of C present!

So your R would be like A^2/(B C^2)