What is the molar concentration of ammonia in a 35% w/w solution for which rho_"solution"=0.88*g*mL^-1?

1 Answer
Jul 2, 2017

We can address the number of ammonia molecules in conc. ammonia.........

Explanation:

Concentrated ammonia is an aqueous solution of ammonia in water. Pure ammonia is a room temperature gas.

At room temperature, the density of a saturated solution in water is rho=0.88*g*mL^-1, and has a concentration of 35%w/w...

And we can thus work out its concentration in mol*L^-1....

((0.88*g*mL^-1xx35%)/(17.03*g*mol^-1))/(1xx10^-3*L*mL^-1)=18.1*mol*L^-1

And thus in 10*L conc. ammoniacal solution, there are 180.1*mol ammonia, i.e. ....

180.1*molxx6.022xx10^23*"ammonia molecules"*mol^-1=

"A lot of ammonia molecules."

Of course in this solution there are still a lot more water molecules, each of which contributes one oxygen atom, and 2 hydrogen atoms.