ChEmIsTrY!!!!!! A Few Things I Don't Get?

Question

1. Plantinum is added to a mixture of sulfur and oxygen speeding the production of sulfur trioxide.

a. temperature c. surface area of reactants
b. concentration d. presence of a catalyst
of reactants

2. A chemist speeds up a reaction by stirring a solid in a liquid with
which it reacts.

a. temperature c. surface area of reactants
b. concentration d. presence of a catalyst
of reactants

3. Under some conditions an instant photograph develops faster when placed in a pocket close to the photographers body.

a. temperature c. surface area of reactants
b. concentration d. presence of a catalyst
of reactants

4. Some people are unable to digest milk products effectively because they lack a certain enzyme.

a. temperature c. surface area of reactants
b. concentration d. presence of a catalyst
of reactants

Answer 1

d - platinum is speeding up the reaction (catalyst)
c - the liquid comes into contact with the solid more
a - the temperature from the body helps develop the photo
d - without the enzyme, the reaction doesn't happen as readily

Answer 2

I agree with the other posters on questions 1, 3, and 4.

Question 2 is a concentration issue. As the solid reacts with the liquid, a localize concentration gradient exists. By stirring, this gradient is eliminated and the reaction is sped up by moving the products away from the reagents, and by moving fresh reagents together.

Answer 3

1) d) presence of catalyst (Pt)
2) a) surface area (stirring)
3) a) temperature (persons body)
4) d) presence of catalyst (cetain people do not have the enzyme needed to break down milk products).

Answer 4

d, c, a, d