Solve this conversion problem: 2.50ug = ________ pg.?

Remember in metric each progressive new prefix usually represents a factor of one thousand, so moving the decimal three spaces, in this case micrograms is actually two levels above picograms (nanograms is between them) a microgram is 10^-6 and pico is 10^-12, so to convert to picograms you need to multiply by one million, so 2,500,000 pg is the correct answer.