Question

Calculate the molarity of 22.3 g of MgS in 787 mL of solution.

Answer 1

Given mass of MgS = 22.3 g

Molar mass of MgS = 56.38 g/mol

# of moles of MgS in 22.3 g = Given mass of MgS / Molar mass of MgS

# of moles of MgS = 22.3 g / 56.38 g.mol^-1.

# of moles of MgS = 0.396 moles.

Now molarity is formulated as,

Molarity = # of moles / Volume in L

For MgS, # of moles = 0.396 moles, Volume = 787 mL = 0.787 L

Then,

Molarity of MgS = 0.396 / 0.787 = 0.5032 M

Molarity of MgS is 0.5032 M.

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