A diatomic compound consists of one atom A and one atom B. (a) Calculate the molecular mass of this compound if 1.50575 x 1022 molecules have a mass of 0.7005 g. (b) If atom B is oxygen, what element could atom A be?

(a) To calculate the molecular mass of the compound, we first need to find out how many moles are in 0.7005 g of the compound. We know that one mole of any substance contains Avogadro's number of molecules, which is approximately 6.022 x 10^23 molecules.

Step 1: Calculate the number of moles in 0.7005 g of the compound. Number of moles = Number of molecules / Avogadro's number Number of moles = 1.50575 x 10^22 molecules / 6.022 x 10^23 molecules/mole Number of moles = 0.025 moles

Step 2: Calculate the molecular mass of the compound. Molecular mass = Mass of the compound / Number of moles Molecular mass = 0.7005 g / 0.025 moles Molecular mass = 28.02 g/mole

(b) If atom B is oxygen, the atomic mass of oxygen is approximately 16 g/mole. To find out what element atom A could be, we subtract the atomic mass of oxygen from the molecular mass of the compound.

Atomic mass of A = Molecular mass - Atomic mass of B Atomic mass of A = 28.02 g/mole - 16 g/mole Atomic mass of A = 12.02 g/mole

The atomic mass of 12.02 g/mole is close to the atomic mass of carbon, which is approximately 12.01 g/mole. Therefore, atom A could be carbon.