Exemplar Problems

Problem 15 : The molar mass of sulfur hexafluoride (SF₆) can be calculated by summing the molar masses of its constituent atoms:

• Sulfur (S): 32.07 g/mol
• Fluorine (F): 18.99 g/mol (approximate, as fluorine has multiple isotopes) So, the molar mass of SF₆ is (32.07 + 6 \times 18.99 = 32.07 + 113.94 = 146.01 , \text{g/mol}).

Solution :

To calculate the molar mass of sulfur hexafluoride (SF₆), you can sum the molar masses of its constituent atoms, as you correctly stated. Here’s the step-by-step solution:

Step 1: Determine the molar masses of each atom in SF₆:

• Sulfur (S): 32.07 g/mol
• Fluorine (F): 18.99 g/mol (approximate, as fluorine has multiple isotopes)

Step 2: Calculate the total molar mass of SF₆ by multiplying the molar mass of fluorine by the number of fluorine atoms in SF₆ (which is 6) and then adding the molar mass of sulfur:

Molar mass of SF₆ = Molar mass of S + (6 × Molar mass of F) Molar mass of SF₆ = 32.07 g/mol + (6 × 18.99 g/mol)

Step 3: Perform the calculations:

Molar mass of SF₆ = 32.07 g/mol + (6 × 18.99 g/mol) Molar mass of SF₆ = 32.07 g/mol + 113.94 g/mol

Step 4: Add the molar masses together:

Molar mass of SF₆ = 32.07 g/mol + 113.94 g/mol Molar mass of SF₆ = 146.01 g/mol

So, the molar mass of sulfur hexafluoride (SF₆) is approximately 146.01 grams per mole (g/mol).