Answer: The mass of magnesium chloride is 257.1 grams.
Step-by-step explanation:
To calculate the mass of magnesium chloride for given number of moles, we use the equation:

We are given:
Moles of magnesium chloride = 2.70 moles
Molar mass of magnesium chloride = 95.21 g/mol
Putting values in above equation, we get:

Hence, the mass of magnesium chloride is 257.1 grams.