Question

Two chemicals A and B are combined to form a chemical C. The rate, or velocity, of the reaction is proportional to the product of the instantaneous amounts of A and B not converted to chemical C. Initially, there are 40 grams of A and 50 grams of B, and for each gram of B, 2 grams of A is used. It is observed that 15 grams of C is formed in 10 minutes. How much is formed in 20 minutes? (Round your answer to one decimal place.)

Answer 1

Answer:

The correct answer is 23,4375 grams of C.

Explanation:

First, we will identify the limiting reagent, which is the one consumed first. Since each gram of B consumes two grams of A, the product to be consumed first is A.

We calculate the amount of A and B that is consumed in the first 10 minutes is 5 grams of B and 10 grams of A.

Now we calculate the constant that relates the speed of reaction to the amount of reagent in each component.

20 grams of B and 40 grams of A will react completely given the limiting reagent A. We calculate the constant that relates the reaction speed (grams of product/time) with the instantaneous amounts of unconverted A and B. We calculate the constant that relates the reaction speed (grams of product/time) with the instantaneous amounts of unconverted A and B. We calculate the constant that relates the reaction speed (grams of product/time) with the instantaneous amounts of unconverted A and B.

So:

15g/10min = k*(20g*40g)

k=1.5 g/min / 800 g^2

k=1,875 *10^-3 g^3 /min

Now, we calculate the amount of reagent that forms when 20 minutes pass:

x / 10 min = 1,875 *10^-3 g^3/min * (15g * 30g)

x= 8,4375 grams

So we can say that after 20 minutes, 23.4375 grams of C will form.

Have a nice day!