No, one mole of chlorine gas does not have a mass of 35.45 grams. Here's why:

* Chlorine gas exists as a diatomic molecule (Cl₂). This means each molecule of chlorine gas contains two chlorine atoms.

* The atomic mass of chlorine is 35.45 g/mol.

* Therefore, the molar mass of chlorine gas (Cl₂) is 2 * 35.45 g/mol = 70.90 g/mol.

So, one mole of chlorine gas (Cl₂) has a mass of 70.90 grams.