Question

What is the molarity of a solution composed of 4.73 g of potassium iodide (KI) dissolved in enough water to make 0.169 L of solution? Answer in units of M.

Answer 1

[KI] = 0.17 M

Step-by-step explanation:

We determine the moles of solute:

Mass / Molar mass → 4.73 g / 166 g/mol = 0.0285 moles

Molarity (mol/L) is defined as moles of solute in 1L of solution

It is a sort of concentration

M = 0.0285 mol / 0.169L = 0.17 M

Instead of making the division (mol/L), we can also try this rule of three:

In 0.169 L we have 0.0285 moles of solute

in 1 L we must have ___ (1 . 0.0285) / 0.169 = 0.17 mol/L