Question

There is about 1.0 g of calcium as Ca2+ in 1.0 L of milk. What is the molarity of Ca2+ in milk?

Answer 1

The molarity of Ca²⁺ in milk is calculated by dividing the mass of calcium in the milk, 1.0 g, by the molar mass of calcium, then dividing that result by the volume of milk in liters. The molarity of Ca²⁺ in milk is 0.02494 M.

Step-by-step explanation:

To determine the molarity of Ca²⁺ in milk, we use the following data: there is about 1.0 g of calcium in 1.0 L of milk. The molar mass of calcium is approximately 40.08 g/mol. Therefore, we can calculate the number of moles of Ca²⁺ in 1.0 L of milk and hence the molarity, which is moles of solute per liter of solution.

Number of moles = mass (g) / molar mass (g/mol)
Number of moles = 1.0 g / 40.08 g/mol = 0.02494 moles

The molarity (M) is then given by:
Molarity = moles of solute/liters of solution
Molarity = 0.02494 moles / 1.0 L
Molarity = 0.02494 M

Therefore, the molarity of Ca²⁺ in milk is 0.02494 M.

Answer 2

Step-by-step explanation:

It is known that molarity is the number of moles present in a liter of solution.

Molarity =
`\frac{\text{no. of moles}}{volume}`

Also, number of moles equal mass divided by molar mass. And, molar mass of calcium is 40.07 g/mol.

No. of moles =
`\frac{mass}{\text{molar mass}}`

=
`(1.0 g)/(40.07 g/mol)`

= 0.025 mol

Therefore, calculate the molarity as follows.

Molarity =
`\frac{\text{no. of moles}}{volume}`

=
`(0.025 mol)/(1.0 L)`

= 0.025 M

Thus, we can conclude that molarity of
`Ca^(2+)` in milk is 0.025 M.