Question

In the laboratory you are asked to make a 0.694 m copper(II) iodide solution using 455 grams of water. How many grams of copper(II) iodide should you add

Answer 1

100.2g of CuI₂ you must add

Step-by-step explanation:

Molality, m, is defined as the ratio between moles of solute and kg of solvent.

In the problem, you have a 0.694m of copper (II) iodide -CuI₂, molar mass: ‎317.35 g/mol-. That means there are 0.694 moles of CuI₂ per kg of water.

As you have 455g = 0.455kg of water -solvent-, moles of CuI₂ are:

0.455kg ₓ (0.694 moles CuI₂ / kg) = 0.316 moles of CuI₂

Using molar mass, grams of CuI₂ in the solution are:

0.316moles CuI₂ ₓ (317.35g / mol) =

100.2g of CuI₂ you must add