Question

Blood serum is typically about 0.0044 M in K+ (aq). Calculate the mass of the potassium ions in 4,785. mL of blood serum. The molar mass of potassium is 39.10 g/mol

Answer 1

0.823 g.

Step-by-step explanation:

• Molarity (M) is defined as the no. of moles of solute dissolved in a 1.0 L of the solution.

M = (no. of moles of K⁺)/(Volume of the solution (L).

∵ no. of moles of K⁺ = (mass/molar mass) of K⁺.

∴ M = (mass/molar mass) of K⁺/(Volume of the solution (L).

M = 0.0044 M.

Volume of the solution = 4785.0 mL = 4.785 L.

mass of K⁺ = ??? g.

molar mass of K⁺ = 39.01 g/mol.

∴ mass of K⁺ = (M)((molar mass of K⁺)(volume of the solution (L)) = (0.0044 M)(39.10 g/mol)(4.785 L) = 0.823 g.