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

Answer:

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.