How many molecules are contained in 2.8 grams of carbon monoxide (CO)?

$6.02\cdot10^{22}$

Explanation

6.02 • 10²² molecules

From the periodic table we learn that carbon monoxide has a molecular mass of 28, or 12 + 16.  Thus we have 0.1 mole of the compound, 0.1 times Avogadro's number yields the answer.)