Question

you have a 0.5 m mgso4 stock solution available. calculate the volume of the stock solution needed to make 2.0 l of 0.20 m mgso4.

Explanation:

Step1: Use the dilution formula

The dilution formula is \(C_1V_1 = C_2V_2\), where \(C_1\) is the initial concentration, \(V_1\) is the initial volume (stock solution volume we need to find), \(C_2\) is the final concentration, and \(V_2\) is the final volume.
Given \(C_1=0.5\space M\), \(C_2 = 0.20\space M\), \(V_2=2.0\space L\).
We need to solve for \(V_1\). Rearranging the formula gives \(V_1=\frac{C_2V_2}{C_1}\).

Step2: Substitute the values into the formula

Substitute the values: \(V_1=\frac{0.20\space M\times2.0\space L}{0.5\space M}\).
First, calculate the numerator: \(0.20\times2.0 = 0.40\).
Then divide by \(0.5\): \(V_1=\frac{0.40}{0.5}=0.8\space L\).

Answer:

\(0.8\space L\) (Option 3)