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 25 grams of c is formed in 6 minutes. how much (in grams) is formed in 12 minutes? (round your answer to one decimal place.) grams what is the limiting amount (in grams) of c after a long time? grams how much (in grams) of chemicals a and b remains after a long time? a grams b grams