<span>7.75% nitrogen in the sample.
The balanced reaction of HCl and NH3 is
HCl + NH3 = NH4Cl
Which means that 1 mole of HCl will neutralize 1 mole of HN3.
Since we used 83.0 ml of 0.150 m HCl, that means that we used
0.083 l * 0.150 mol/l = 0.01245 mol
So we had 0.01245 mol of NH3 which means that we had 0.01245 mol of N
Looking up the atomic weight of nitrogen, we get 14.0067. So
0.01245 * 14.0067 = 0.174383415 g
We now know that the sample had 0.17438 g of nitrogen. Divide by the original mass of the sample, getting
0.17438 / 2.25 = 0.077502222 = 7.7502222%
Rounding the result to 3 significant figures, gives us a mass percentage of 7.75% nitrogen in the original sample.</span>
Answer:
0.5×10² pm
Explanation:
Given data:
Frequency of x-ray = 6×10¹⁸ Hz
Wavelength of x-ray = ?
Solution:
Wavelength is designated as "λ" and it is the measured in meter. It is the distance between the two crust of two trough.
Formula:
speed of wave = wavelength × frequency
speed = 3×10⁸ m/s
now we will put the values in formula.
3×10⁸ m/s = λ × 6×10¹⁸ Hz
Hz = s⁻¹
λ = 3×10⁸ m/s / 6×10¹⁸ s⁻¹
λ = 0.5×10⁻¹⁰ m
m to pm
0.5×10⁻¹⁰ m × 10¹² pm/1m
0.5×10² pm
Finding percent composition is fairly easy. You only need to divide the mass of an element by the total mass of the compound. We can do this one element at a time.
First, let's find the total mass by using the masses of the elements given on the periodic table.
7 x 12.011 (mass of Carbon) = 84.077
5 x 1.008 (mass of Hydrogen) = 5.04
3 x 14.007 (mass of Nitrogen) = 42.021
6 x 15.999 (mass of Oxygen) = 95.994
Add all of those pieces together.
84.077 + 5.04 + 42.021 + 95.994 = 227.132 g/mol is your total. Since we also just found the mass of each individual element, the next step will be very easy.
Carbon: 84.077 / 227.132 = 0.37016 ≈ 37.01 %
Hydrogen: 5.04 / 227.132 = 0.022189 ≈ 2.22 %
Nitrogen: 42.021 / 227.132 = 0.185 ≈ 18.5 %
Oxygen: 95.994 / 227.132 = 0.42263 ≈ 42.26 %
You can check your work by making sure they add up to 100%. The ones I just found add up to 99.99, which is close enough. A small difference (no more than 0.03 in my experience) is just a matter of where you rounded your numbers.
Answer:
PLEASE MARK AS BRAINLIEST!!
Explanation:
Apply rubbing alcohol, hairspray, or hand sanitizer to dilute the stain, making it easier to remove during the wash. These solvents help tackle most types of ink stains, but remember to test the stained garment for colorfastness first, as they can also attack fabric dyes and cause further damage.