Answer:
Abundance of isotope 79Br=51% and abundance of 81Br=49%
Step-by-step explanation:
We are given that
Mass of 79Br=78.9183 u
Mass of 81Br=80.9163 u
Average atomic mass of bromine=79.90 u
We have to find the relative abundance of the two bromine isotopes.
Let x be the abundance of 79Br
Then , abundance of 81Br isotopes=1-x
Average atomic mass=Mass of isotope(abundance of isotope)+Mass of other isotope(abundance of other isotope)
Using the formula
![79.90=78.9183x+(1-x)80.9163](https://tex.z-dn.net/?f=79.90%3D78.9183x%2B%281-x%2980.9163)
![79.90=78.9183x+80.9163-80.9163x](https://tex.z-dn.net/?f=79.90%3D78.9183x%2B80.9163-80.9163x)
![79.90-80.9163=-1.998x](https://tex.z-dn.net/?f=79.90-80.9163%3D-1.998x)
![-1.0163=-1.998x](https://tex.z-dn.net/?f=-1.0163%3D-1.998x)
![x=\frac{1.0163}{-1.998}=0.51](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B1.0163%7D%7B-1.998%7D%3D0.51)
Percentage of isotope with abundance 0.51=
%
Abundance of other isotope=1-0.51=0.49
Percentage of other isotope with abundance 0.49=
%
Answer:
74
Step-by-step explanation:
Answer:
75%
Step-by-step explanation:
Each quartile is 25%; the answer asks for 70% and below, which is the first through third quartile.
Answer:
Width of the garden box = 4 feet
Step-by-step explanation:
Given that:
Length of garden box = 22 feet
Let,
w be the width of garden box
It is also given that:
The length of a garden box is 6 feet longer than 4 times the width.
L = 4w + 6
Putting L = 22
22 = 4w + 6
22 - 6 = 4w
4w = 16
Dividing both sides by 4
![\frac{4w}{4}=\frac{16}{4}\\w=4](https://tex.z-dn.net/?f=%5Cfrac%7B4w%7D%7B4%7D%3D%5Cfrac%7B16%7D%7B4%7D%5C%5Cw%3D4)
Hence,
Width of the garden box = 4 feet