Question

Anyone who can see the idea in this question:
Concentrated ammonia water solution containing 25% NH3 and has a density of 0.91 g / ml. How much 2.0 M ammonia solution can be prepared from 50 ml of concentrated?
Question for me is... I'm I going to do the calculations for NH3 or ammonia water (NH4OH) with equation C = p/M [C=concentration, p=density, M=molar mass]

Answer 1

Convert 2.0M to percent volume/volume

then when you have it converted

just use

(%conc wanted in final solution/%conc wanted in stock solution)50mL
= mL of stock solution needed

Answer 2

You know you are making a 2.0M solution so just convert that by using the 50mL to find the moles than use molecular mass to find the grams.

Lets just assume it is Percent Mass volume actually

then use the formula

\[Percent_{m/v} = (\frac{Grams OfNH_3}{Volume of Solution})100\]

Answer 3

In this case ignore percent volume/volume it is actually 25% mass/volume

I'm pretty sure in this problem density is pretty useless there might be another way of solving this but this seems like the most obvious.