To find the number of moles in a sample, you can use the formula: Number of moles = (Number of particles)/(Avogadro's number) Avogadro's number is approximately 6.022 x 10^23 particles per mole. In this case, the number of particles is 2.6 x 10^24. So, the number of moles can be calculated as follows: Number of moles = (2.6 x 10^24)/(6.022 x 10^23) Number of moles ≈ 4.32 moles Therefore, there are approximately 4.32 moles in the sample of Cl2.