Question

How many moles of MgCl2 where needed to make a 650.0 mL solution a concentration of 0.962 M?

Answer 1

Answer:

0.625 moles MgCl₂

Explanation:

Since you were given a molarity value and volume, you should use the molarity equation to find moles. The equation looks like this:

Molarity (M) = moles / volume (L)

To find moles, you need to (1) convert mL to L (by dividing by 1,000) and then (2) plug the numbers into the formula and simplify to find moles. The final answer should have 3 sig figs as the lowest amount of sig figs in a given value is 3.

Step 1:

650.0 mL / 1,000 = 0.6500 L

Step 2:

Molarity = moles / volume

0.962 M = moles / 0.6500 L

(0.962 M) x (0.6500 L) = moles

0.625 = moles