What volume of concentrated ammonia would you dilute to 1.50 L to obtain a solution of 0.178 M. The concentrated ammonia solution has a specific gravity of 0.90 and is 27% (w/w).

Question

Give your answer in mL to one decimal place.

Answer 1

1.50 L x 0.178 mol/L = 0.267 moles NH₃ required

How many mls of the concentrated NH₃ do we need to obtain the required 0.267 moles NH₃?

0.267 moles NH₃ x 17 g NH₃/mol = 4.539 g NH₃ is what is needed

The concentrated solution is 27 g NH₃ / 100 g solution

27 g NH₃ / 100 g soln = 4.539 g NH₃ / x g soln and x = 16.8 g soln needed

16.8 g soln x 1 ml/0.9 g = 18.7 mls of concentrated NH₃ solution

So, you would need 18.7 mls of the concentrated solution diluted to a final volume of 1.5 L