Commercial concentrated aqueous ammonia is 28% NH3
by mass and h...

Question

Commercial concentrated aqueous ammonia is 28% NH3 
by mass and has a density of 0.90 g>mL. What is the molarity of this solution?

Accepted Answer

Hey everyone, we're told at 25 degrees Celsius a 32% by mass. Hydrochloric solution has a density of 1.161 g per mil. Leader Expresses concentration in molar itty first we need to recognize that 32% mass of hydrochloric solution essentially means that we have 32.0 g of hydrochloric acid In 100 g of solution. Since we have a total of 100%. So that means we have 100 g of our solution. Now to calculate our polarity, we need to calculate our moles of hydrochloric acid and our volume. So starting off with our moles of hydrochloric acid, we're going to take 32.0 g of hydrochloric acid And using dimensional analysis And our molar mass of hydrochloric acid, we know that we have 36.458g of hydrochloric acid, Her one mole of hydrochloric acid. So when we calculate this up, We end up with a value of 0. mol of hydrochloric acid. So now let's go ahead and calculate the volume of our solution. Starting off with 100 g of solution, We're going to use dimensional analysis again and we're going to take the density which is 1.161 g of solution per one millimeter. But since polarity is calculated in leaders, we have to convert our milliliters into leaders. So we have 10 to the third milliliters or one leader. So when we calculate this out, we end up with a volume of 0.0861 leaders. Now we can go ahead and calculate our polarity Again. Our polarity is going to be our moles of solute, which is 0.8777 mol of hydrochloric acid, divided by our leaders of solution, which is 0.0861 leaders. So when we calculate this out, we end up with a polarity of 10.2 molar, which is going to be our final answer. Now. I hope that made sense and let us know if you have any questions.

Watch next