5. The number of moles of molecules in a 12.0-gram sample of Cl2 is A) 12.0 moles
B) 12.0 x 35.5 moles
C) 12.0/71.0 mole
D) 12.0/35.5 mole

Considering the definition of molar mass, the number of moles of molecules in a 12 grams sample of Cl₂ is = 0.169 moles.

Molar mass is the mass of one mole of a substance, which can be an element or a compound.

In other words, molar mass is the amount of mass that a substance contains in one mole.

Therefore, knowing the molar mass, the number of moles in a container can be calculated using the expression:

In this case, you have 12 grams sample of Cl₂, whose molar mass is 71 .

So, the number of moles can be calculated as:

Solving:

number of moles= 0.169 moles

Finally, the number of moles of molecules in a 12 grams sample of Cl₂ is = 0.169 moles.

Learn more about molar mass and number of moles:

mole

Explanation:

Given parameters:

Mass  = 12g

Molecule  = Cl₂

Unknown:

Number of moles of molecules  = ?

Solution:

To solve this problem, we use the expression below:

   Number of moles  =  

 molar mass of  Cl₂  = 2 (35.5)  = 71g/mol

 Number of moles  = mole

the answer is barium and copper bromide