Question

A nitric solution containing 308g of HNO3 per liter of solution has a density of of 1.35g/cm3.
1. Calculate the mass percent of HNO3 in this solution.
2. Calculate the molality of HNO3 in this solution.

I already know that the mass%=mass solute/mass solution.

I'm confused how to i set up the density part? Please explain step by step. I have to study this for an upcoming test.

I will reward you with a trophy.

Answer 1

Look, I'm pretty crappy with chemistry but I'm trying to learn it, I did a ton of these questions yesterday.

1.I'm pretty sure what this means is that 308g is your solute, but your solution will be determined from the density.

d=m/v
v=1000g(1 liter)
d=1.35g/cm

mass=d x v

mass=1350 grams or 1.35 liters

your formula of mass%=308/1350 x 100

I got 22.8%. I'm pretty sure this is right

Answer 2

As for the 2nd one, molarity is
#of moles/liters

that means you need to first calculate the amount of moles, which is
given weight/formula weight

HNO3

given weight=308gram

h=1
n=14
o3=48
formula weight=63

308/63=roughly 4.8 moles

4.8/solution

solution is 1 liter

since i'm pretty sure the molarity formula HAS to be in liters

4.8 moles, 1 liter

4.8/1=4.8 molarity

Answer 3

i hope i'm right lol..

Answer 4

@JFraser
can you check this for me?

Answer 5

Yes you're correct! Thank you!!

Answer 6

LOL I am??? This might be the first chemistry question I did correctly in 6 months, that's cool..

Answer 7

If you have anymore of these, I'll gladly look at them as I need the practice too..

Answer 8

Lol yeah chem can be crazy hard. The exam is this Friday too, I'm glad you showed the steps because I wasn't sure if I was solving it right. Thanks for clearing up my confusion. Lol

Answer 9

Yeah, gas laws are especially a pain to remember. (charles,boyles etc) It may take a lot of practice, also requires critical reading skills...