Starting with 100 grams of uranium-238, after one half life has gone by, how many grams of uranium-238 will remain?
a._12.5 grams
b._25 grams
c._50 grams
d._100 grams

How does a catalyst increase the speed of a reaction? a. the catalyst eliminates the activated complex stage, allowing products to form immediately. b. the catalyst lowers the energy level of the reactants, making it easier for them to react. c. the catalyst makes it easier for the activated complex to form, lowering the activation energy. d. the catalyst raises the energy level of the products, making the reaction finish sooner. reset next