What is the molar mass of chlorine gas? 35.5 g/mol 6.02 x 10^23 g/mol 70.9 g/mol 1.20 x 10^23 g/mol
The Correct Answer and Explanation is:
Correct Answer: 70.9 g/mol
Explanation:
Chlorine is a chemical element with the symbol Cl and an atomic mass of approximately 35.5 grams per mole. In nature, chlorine does not exist as a single atom but rather as a diatomic molecule, Cl₂, which means each molecule of chlorine gas contains two chlorine atoms.
To find the molar mass of chlorine gas, you must account for both atoms in the diatomic molecule. Therefore:
Molar mass of Cl₂ = 2 × 35.5 g/mol = 70.9 g/mol
This value means that one mole of chlorine gas, which contains 6.022 × 10²³ molecules of Cl₂ (Avogadro’s number), has a mass of 70.9 grams.
Let’s examine the other choices and why they are incorrect:
- 35.5 g/mol is the atomic mass of a single chlorine atom, not the Cl₂ molecule.
- 6.02 x 10²³ g/mol represents the number of particles (atoms or molecules) in one mole, not a mass.
- 1.20 x 10²³ g/ is not a valid unit and has no relation to molar mass.
The molar mass is a critical concept in chemistry because it allows chemists to convert between mass and number of moles when working with chemical reactions. Since chlorine gas is commonly used in industry and labs, knowing its molar mass is essential when measuring out quantities for reactions or studying gas behavior using the ideal gas law.
In summary, chlorine gas is diatomic and its correct molar mass is 70.9 grams per mole, which is used in stoichiometric calculations and chemical analyses involving this element.
