Answer:
4.55 * 10^23 molecules
Explanation:
This is a conversion problem. We know that one mole has 6.022 *10^23 particles or molecules so we can use this as a conversion factor.
0.755 mol ( 6.022*10^23 molecules/ 1 mol)
=4.55*10^23 molecules
The question is incomplete,the complete question :
Calculate the molality of a 10.0% (by mass) aqueous solution of hydrochloric acid:
a) 0.274 m
b) 2.74 m
c) 3.05 m
d) 4.33 m
e) the density of the solution is needed to solve the problem
Answer:
The molality of a 10.0% (by mass) aqueous solution of hydrochloric acid is 3.05 mol/kg.
Explanation:
10.0% (by mass) aqueous solution of hydrochloric acid.
10 grams of HCl is present in 100 g of solution.
Mass of HCl = 10 g
Mass of solution = 100 g
Mass of solution = Mass of solute + Mass of water
Mass of water = 100 g - 10 g = 90 g
Moles of HCl = 
Mass of water in kilograms = 0.090 kg
Molality = 
The molality of a 10.0% (by mass) aqueous solution of hydrochloric acid is 3.05 mol/kg.
Answer:
Honestly, I'm not even sure what the incorrect student was trying to do. The correct answer is:
( ) = the number of elements
(1)N2 and (3)H2
I think the student added the N2 and H2 to "balance" the chemical equation when instead they should have tried the balance the equation by making sure the atoms on the reactant side are equal to the atoms on the product side. You do this by multiplying the atoms on the reactant side until they equal the product side (not by adding them, as the student did).
We have that the Concentration of solution B is 2.5 times more than solution A's concentration.
<h3>UV(Ultra violent) rays</h3>
Question Parameters:
Upon UV-analysis, Solution B gave an absorbance of 1.0
Solution A gave an absorbance of 0. 4
Generally the equation for the Absorbance is mathematically given as
A = e*c*L
Therefore
For A solution
![0.4 = e*[cA]*L](https://tex.z-dn.net/?f=0.4%20%3D%20e%2A%5BcA%5D%2AL)
For B solution
![1.0 = e*[cB]*L](https://tex.z-dn.net/?f=1.0%20%3D%20e%2A%5BcB%5D%2AL)
Hence
![\frac{0.4}{ 1} = \frac{[cA]}{ cB}](https://tex.z-dn.net/?f=%5Cfrac%7B0.4%7D%7B%201%7D%20%3D%20%5Cfrac%7B%5BcA%5D%7D%7B%20cB%7D)
[cB] = 2.5 [cA]
Therefore
Concentration of solution B is 2.5 times more than solution A's concentration.
For more information on Wave visit
brainly.com/question/3004869