When orange iodine is exposed to starch it turns blue-black. In an experiment, you placed a cornstarch solution in a small plastic bag. Next, you placed the the bag in a beaker of water containing 10 drops of iodine. If the solution in the plastic bag turned blue-black (Check all that apply)

a. the plastic bag was permeable to cornstarch.
b. the plastic bag was permeable to iodine.
c. the iodine moved into the plastic bag.
d. the cornstarch moved into the beaker.
e. the plastic bag was selectively perme

b brown mice / white sand dunes

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.