To find the molarity of Ca²⁺ ions in milk, we begin by calculating the number of moles of calcium present in 10 grams. The molar mass of calcium (Ca) is approximately 40.08 g/mol.
Next, we use the formula for calculating moles:
Number of Moles = Mass (g) / Molar Mass (g/mol)
Substituting in our values:
Number of Moles = 10 g / 40.08 g/mol ≈ 0.249 moles
Now that we have the number of moles, we can calculate the molarity (M), which is defined as moles of solute per liter of solution:
Molarity (M) = Moles of Solute / Volume of Solution (L)
For our case:
Molarity = 0.249 moles / 1 L = 0.249 M
Therefore, the molarity of Ca²⁺ in milk is approximately 0.249 M. This means that in one liter of milk, there are about 0.249 moles of calcium ions dissolved.