What's the mass of 7.61 x 10^24 molecules of Magnesium sulfate heptahydrate?
1400 g
1900 g
2500 g
31009

Mass = 3100 g

Explanation:

Given data:

Mass of MgSO₄.7H₂O = ?

Number of molecules = 7.61×10²⁴ molecules

Solution:

First of all we will calculate the number of moles of MgSO₄.7H₂O by using Avogadro number.

1 mole contain 6.022×10²³ molecules

7.61×10²⁴ molecules × 1 mol  / 6.022×10²³ molecules

1.26×10¹ mol

12.6 moles

Mass of MgSO₄.7H₂O:

Mass = number of moles × molar mass

Molar mass of MgSO₄.7H₂O = 246 g/mol

Mass = 12.6 mol × 246 g/mol

Mass = 3100 g

the answer is 303.15 or 303