Question

You need to make 300 ml of a 1M stock of lactose, how many grams of lactose do you need?

Answer 1

To make 300 ml of a 1M lactose solution, you need to dissolve 102.69 grams of lactose into the solution, based on lactose’s molar mass of 342.3 g/mol.

Step-by-step explanation:

To make a 300 ml of a 1M solution of lactose, you first need to know the molar mass of lactose, which is approximately 342.3 g/mol. Using the formula:

mass (g) = molarity (M) × volume (L) × molar mass (g/mol)

You would calculate the mass of lactose required as follows:

mass = 1 M × 0.300 L × 342.3 g/mol

mass = 102.69 g of lactose

Therefore, you will need 102.69 grams of lactose to make a 300 ml of a 1M lactose solution. Remember to ensure all measurements are accurate and the lactose is fully dissolved in the solvent to create the stock solution.