Help with Chem problem please/!?

Question

Charcoal reacts with oxygen according to the equation C(s) +O2 (g0. Which change would cause the greatest increase in the rate of reaction?

1) using charcoal in lump form

2)decrease pressre in O2

3)Decreaing in concentration 02

4)using charcaol in powdered form

Explain!

Thanks

Answer 1

Only 4) would cause an increase, since the greater surface area would allow more contact between molecules thereby increasing reaction rate.

All the others would actually de-crease reaction rate (#1 opposite of answer, and #2 and #3 because of Le Chatlier's Principle)