Molarity is defined as the number of moles of solute in 1 L of solution
molarity of stock solution to be prepared - 100 x 10⁻³ mol/L
volume of stock solution to be prepared - 1.2 mL
Therefore number of moles in 1.2 mL - 100 x 10⁻³ mol/L x 1.2 x 10⁻³ L
number of moles of drug - 1.2 x 10⁻⁴ mol
mass of drug required - 1.2 x 10⁻⁴ mol x 181.6 g/mol = 21. 8 mg
21.8 g of drug is required to make the stock solution
Answer:
1.09 M
Explanation:
Let's define the equation that will be used to calculate the final concentration of the resultant calcium nitrate solution. In order to calculate it, we need to find the total number of moles of calcium nitrate and divide by the total volume of the resultant solution:

This equation firstly helps us find the number of moles of calcium nitrate. Multiplying molarity by volume will yield the moles. Adding the moles from the first component to the second component will provide us with the total number of moles of calcium nitrate:

Now, the total volume of this solution can be found by adding the volume values of each component:

Finally, dividing the moles found by the total volume will yield the final molarity:

Use a sieve to separate the water from the iron fillings and sand.
Use a magnet to separate the iron from the sand.