posted by Chuck .
using kinetics explain:
a.the increasing of concentration of reactants increases the rate of reaction.
b.the addition of a catalyst increases the rate at which a reaction will take place.
c.and increase in temperature increases reaction rate.
d.a catalyst grounded into powder is more effective than the solid block.
These are thought questions. Let's hear your thoughts and we can offer suggestions.
c. the increase in temperature, increases the speed and energy of the collisions, causing the reaction to occur faster.
a. by increasing the concentration, there are more particles, which means they will collide more frequently causing a faster reaction.
Your answers to a and c look good.
b. The addition of a catalyst increases the rate of reaction because it offers the reaction an alternative path from reactants to products. Many reactions are slow because they have a high "activation energy"; that is, a high hump which the molecules must get over before the reaction will occur. The reaction is slow because most of the molecules don't have that energy to "get over the hump" so it proceeds slower. The catalyst lowers the activation energy (by providing the alternative path) and more molecules have that lower energy requirement. You can take this and redo it in your own words; this is too long an answer but it provides you with the information to distill it to one or two sentences.
d. A catalyst in poweder form gives MUCH more surface area than in solid block form. Catalyzed reactions often occur on the surface of the catalyst (that's where the alternative pathway comes into the picture) so more surface means more molecules can engage each other.