Find the mass in grams of 2.65 x 10^24 molecules of cl2

Moles of Cl2 = 2.65 x 10^24 / 6.02 x 10^23 = 4.4 moles.

Mass of Cl2 in grams = molar mass of Cl2 x moles of Cl2
                                     = 70.906 x 4.4
                                     = 311.98 grams.

Hope this helps!

Adozen is 12, and your needing to calculate the weight of one medium egg, so i would do 21/12=1.75 per egg, and check your answer by doing 1.75 * 12= 21 : ) : ): ): ): ) i hoped i