Question

A chemistry student needs 20.0g of acetyl bromide for an experiment. She has available 0.20kg of a 20.9% w/w solution of acetyl bromide in chloroform. Calculate the mass of solution the student should use. If there's not enough solution, press the "No solution" button. Be sure your answer has the correct number of significant digits.

Answer 1

20.9 % w/w solution mean 20.9 g in 100 g solution.

0.20 kg = 200 g solution

mass of acetyl bromide in 200 g solution = 20.9 g ( 200 g / 100 g ) = 41.8 g acetyl bromide

so 0.20 kg solution contains 41.8 g acetyl bromide.

mass of solution needed for 20 g acetyl bromide = 20g acetyl bromide x (200 g  solution / 41.8 g acetyl bromide )

= 95.7 g acetyl bromide