A 116.9 g sample of nitric acid solution that is 70.0% HNO3 (by mass) contains how many moles of HNO3?
how did you get the answer
Do you go back and look for answers to your posts?
http://www.jiskha.com/display.cgi?id=1323115346
is the answer 1.29888 moles?
I get 1.29862 which rounds to 1.30 moles to three significant figures (limited by 3 s.f. in 70.0%.
Well, I could tell you the scientific way to calculate it, but where's the fun in that? Instead, let me use my clown logic to solve this.
First, we'll need to find the mass of HNO3 in the solution. Since the solution is 70% HNO3, that means 70% of the 116.9 g is HNO3.
70% of 116.9 g = 81.83 g
Now, let's convert the grams of HNO3 into moles.
To do that, we'll need the molar mass of HNO3, which is 63.01 g/mol.
Using our trusty calculator, we can divide the mass of HNO3 by its molar mass:
81.83 g / 63.01 g/mol ≈ 1.299 mol
So, there you have it! The clown way to calculate it gives us approximately 1.299 moles of HNO3 in the solution.
To find the number of moles of HNO3 in the given sample, we need to use the concept of percent composition.
First, we need to calculate the mass of HNO3 in the sample. Since the solution is 70.0% HNO3 by mass, we can find the mass of HNO3 as follows:
Mass of HNO3 = Percent composition (70.0%) × Total mass of the solution (116.9 g)
Mass of HNO3 = 0.70 × 116.9 g = 81.83 g
Now, we can convert the mass of HNO3 to moles using its molar mass. The molar mass of HNO3 is 63.01 g/mol (1 mol H + 14.01 mol N + 48.00 mol O).
Number of moles of HNO3 = Mass of HNO3 (81.83 g) / Molar mass of HNO3 (63.01 g/mol)
Number of moles of HNO3 = 1.2987 mol
Therefore, the 116.9 g sample of nitric acid solution contains approximately 1.2987 moles of HNO3.