Answer:
5.0 carat x (0.200g / 1 carat) x (1 cm³ / 3.51g) = 0.28 cm³... with 2 sig figs..
Explanation:
USE DIMENSIONAL ANALYSIS. That is the point of this problem. That is why Dr. Zumdahl wrote this problem and put it in his textbook (chpt 1 Problem #57 if you're using the 7th edition, chpt1 problem #63 if you're using his 8th edition).