Question

A chemist prepares a solution of aluminum chloride (AlCl3) by measuring out 11 gr of aluminum chloride (AlCl3) into a 50 ml volumetric flask and filling the flask to the mark with water. Calculate the concentration in mol/L of the chemist's aluminum chloride solution. Be sure your answer has the correct number of significant digits.

Answer 1

Answer:

1.6 M

Explanation:

To answer this question first we calculate the molar mass of AlCl₃, using the atomic weights of Al and Cl:

• AlCl₃ ⇒ 27 g/mol + (35.45 g/mol)*3 = 133.35 g/mol

Now with the molar mass, and the mass weighed, we can calculate mol AlCl₃:

• 11 g AlCl₃ ÷ 133.35 g/mol = 0.082 mol AlCl₃

Finally we calculate concentration in mol/L, keeping in mind that 50mL = 0.05 L:

• 0.082 mol AlCl₃ / 0.05 L = 1.6 M