Answer:
8239.2g
Explanation:
Given parameters:
Number of atoms in Br = 6.2 x 10²⁵atoms
Unknown:
Mass of Br = ?
Solution:
From mole concepts, we know that:
1 mole of a substance contains 6.02 x 10²³ atoms/mol
Molar mass of Br = 80g/mol
6.2 x 10²⁵atoms x
x 80 x
= 8239.2g
A. all magnets have two poles
# moles = mass (g) / Mr (relative atomic mass)
# moles = 458 / ((23*2)+32+(16*4)
# moles= 458 / 142 = 3.2253521126760...
= 3.23 moles
Answer:
6.32 moles of Fe
Explanation:
The given chemical equation is presented as follows;
2Fe + 3Cl₂ → 2FeCl₃
The mass of Cl₂ in the reaction = 336 grams
The molar mass of chlorine gas Cl₂ = 35.435 g/mol
The number of moles, n = Mass/(Molar mass)
The number of moles of Cl₂ in the reaction, n = 336 g/(35.435 g/mol) ≈ 9.842 moles
From the given reaction, 3 moles of Cl₂ react with 2 moles of Fe to produce 2 moles of FeCl₃
By the law of definite proportions, we have that 9.482 moles of Cl₂ will react with approximately 9.482 × 2/3 = 6.32 moles of Fe to produce approximately 6.32 moles of FeCl₃
Therefore, approximately 6.32 moles of Fe will be required to react with 336 grams of Cl₂.
Answer:
2.32 m
Explanation:
So, according to definition of mole fraction:
![Mole\ fraction\ of\ benzene=\frac {n_{benzene}}{n_{benzene}+n_{toluene}}](https://tex.z-dn.net/?f=Mole%5C%20fraction%5C%20of%5C%20benzene%3D%5Cfrac%20%7Bn_%7Bbenzene%7D%7D%7Bn_%7Bbenzene%7D%2Bn_%7Btoluene%7D%7D)
Mole fraction = 0.176
Applying values as:
![0.176=\frac {n_{benzene}}{n_{benzene}+n_{toluene}}](https://tex.z-dn.net/?f=0.176%3D%5Cfrac%20%7Bn_%7Bbenzene%7D%7D%7Bn_%7Bbenzene%7D%2Bn_%7Btoluene%7D%7D)
![0.176\times ({n_{benzene}+n_{toluene}})={n_{benzene}}](https://tex.z-dn.net/?f=0.176%5Ctimes%20%28%7Bn_%7Bbenzene%7D%2Bn_%7Btoluene%7D%7D%29%3D%7Bn_%7Bbenzene%7D%7D)
So,
![0.176\times n_{toluene}}=0.824\times {n_{benzene}}](https://tex.z-dn.net/?f=0.176%5Ctimes%20n_%7Btoluene%7D%7D%3D0.824%5Ctimes%20%7Bn_%7Bbenzene%7D%7D)
![{n_{benzene}}=\frac {0.176}{0.824}\times n_{toluene}}](https://tex.z-dn.net/?f=%7Bn_%7Bbenzene%7D%7D%3D%5Cfrac%20%7B0.176%7D%7B0.824%7D%5Ctimes%20n_%7Btoluene%7D%7D)
![{n_{benzene}}=0.2136\times n_{toluene}}](https://tex.z-dn.net/?f=%7Bn_%7Bbenzene%7D%7D%3D0.2136%5Ctimes%20n_%7Btoluene%7D%7D)
Also, Molar mass of toluene = 92.14 g/mol
Thus,
The formula for the calculation of moles is shown below:
![moles = \frac{Mass\ taken}{Molar\ mass}](https://tex.z-dn.net/?f=moles%20%3D%20%5Cfrac%7BMass%5C%20taken%7D%7BMolar%5C%20mass%7D)
![Mass=92.14\times n_{toluene}}\ g](https://tex.z-dn.net/?f=Mass%3D92.14%5Ctimes%20n_%7Btoluene%7D%7D%5C%20g)
Also, 1 g = 0.001 kg
So,
![Mass\ of\ toluene=0.09214\times n_{toluene}}\ kg](https://tex.z-dn.net/?f=Mass%5C%20of%5C%20toluene%3D0.09214%5Ctimes%20n_%7Btoluene%7D%7D%5C%20kg)
Molality is defined as the moles of the solute present in 1 kg of the solvent.
It is represented by 'm'.
Thus,
![Molality\ (m)=\frac {0.2136\times n_{toluene}}{0.09214\times n_{toluene}}](https://tex.z-dn.net/?f=Molality%5C%20%28m%29%3D%5Cfrac%20%7B0.2136%5Ctimes%20n_%7Btoluene%7D%7D%7B0.09214%5Ctimes%20n_%7Btoluene%7D%7D)
<u>Molality of benzene = 2.32 m</u>