In this experiment it takes in this experiment it takes about 10 microliters of solution to produce a spot 1 cm in diameter. if the co (no3) 2 solution contains about 6 g co^2 + per liter, how many micrograms of co^2 + ion are there in one spot

We use the dimensional analysis approach. This is done by manipulating the units such that the same units are found in the numerator and denominator side so that you can cancel them. In the end, the final answer should have the unit of what was asked for. Note that 1 microliter is 10⁻⁶ L and 1 microgram is 10⁻⁶ g.

(6 g Co²⁺/L) (10⁻⁶ L/1 microliter) (10 microliters) (1 microgram/10⁻⁶ g) = 0.6 micrograms