# 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 $\rho = 0.88 \cdot g \cdot m {L}^{-} 1$, and has a concentration of 35%w/w...

And we can thus work out its concentration in $m o l \cdot {L}^{-} 1$....

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

And thus in $10 \cdot L$ conc. ammoniacal solution, there are $180.1 \cdot m o l$ ammonia, i.e. ....

$180.1 \cdot m o l \times 6.022 \times {10}^{23} \cdot \text{ammonia molecules} \cdot m o {l}^{-} 1 =$

$\text{A lot of ammonia molecules.}$

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