# A level chemistry help !

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#1
A sample of tungsten has a relative atomic mass of 183.4 and consists of three isotopes, 182W, 183W and 184W
In this sample, the ratio of abundances of the isotopes 182W :183W is 1:1

State why the isotopes of tungsten have identical chemical properties.
Calculate the percentage abundance of the 184W isotope in this sample.
[4 marks]

Why isotopes of tungsten have identical chemical properties
0
4 weeks ago
#2
Isotopes have a different number of neutrons but the same electron configuration.
2
#3
(Original post by Anonymous17!)
Isotopes have a different number of neutrons but the same electron configuration.
Thank you would the ratio of the three isotopes be 18 ?
0
4 weeks ago
#4
(Original post by Asha2003)
Thank you would the ratio of the three isotopes be 18 ?
I got 13. Idk if it’s right but you need to work it out algebraically I think. If you need any further help, just quote me in this thread but here are some tips (again, don’t know if it’s right or not):

1. The ratio for 182:183 is 1:1. If you let the abundance of 182 equal x, then the abundance of 183 is also x. All abundances need to add up to 100, so if you form an equation you should get:

(182x) + (183x) + (184 x 100-2x) All divided by 100 = 183.4

If you solve that equation, you should get the value of x. Then remember that for 184 the total abundance is 100-2x. If you have a mark scheme, check and see if this method is right, if not then I’m not sure how to solve it.
Last edited by Anonymous17!; 4 weeks ago
0
4 weeks ago
#5
183.4 = (182x)+(183x)+(184 x (100-2x))
(MULTIPLY BY 100)

18340 = 365x + 18400-368x

-60 = -3x

x= 20

Remember that the ratio of abundances of the isotopes 182W :183W is 1:1 so their percentage abundance is both 20%

100 is the total abundance.

Therefore, 100-20-20= 60

So 184W= 60%

Lol i'm not great at chemistry, but i hope that helps x
Last edited by lfavourl; 4 weeks ago
0
#6
(Original post by Anonymous17!)
I got 13. Idk if it’s right but you need to work it out algebraically I think. If you need any further help, just quote me in this thread but here are some tips (again, don’t know if it’s right or not):

1. The ratio for 182:183 is 1:1. If you let the abundance of 182 equal x, then the abundance of 183 is also x. All abundances need to add up to 100, so if you form an equation you should get:

(182x) + (183x) + (184 x 100-2x) All divided by 100 = 183.4

If you solve that equation, you should get the value of x. Then remember that for 184 the total abundance is 100-2x. If you have a mark scheme, check and see if this method is right, if not then I’m not sure how to solve it.
Thank youuu , that makes much sense, I'll try your method thanks for the help
1
#7
(Original post by lfavourl)
183.4 = (182x)+(183x)+(184 x (100-2x))
(MULTIPLY BY 100)

18340 = 365x + 18400-368x

-60 = -3x

x= 20

Remember that the ratio of abundances of the isotopes 182W :183W is 1:1 so their percentage abundance is both 20%

100 is the total abundance.

Therefore, 100-20-20= 60

So 184W= 60%

Lol i'm not great at chemistry, but i hope that helps x
Thankkk youuu !! I needed this
0
4 weeks ago
#8
(Original post by Asha2003)
A sample of tungsten has a relative atomic mass of 183.4 and consists of three isotopes, 182W, 183W and 184W
In this sample, the ratio of abundances of the isotopes 182W :183W is 1:1

State why the isotopes of tungsten have identical chemical properties.
Calculate the percentage abundance of the 184W isotope in this sample.
[4 marks]

Why isotopes of tungsten have identical chemical properties
Remember that: each isotope has the same number of electrons despite differing number of neutrons. electron configuration determines chemical property.

The question needs you to do a little bit of algebra (or well Id do it like that):

We can assume that the abundance of 182 and 183 is x and x respectively (due to the 1:1 ratio). Therefore the abundance of 184 would be (100-2x). Remember that:

182W abundance + 183W abundance + 184W abundance would equal to 100 (as a percentage).

To figure out abundance of one isotope we do (Isotopic mass X percentage abundance). Algebraically we can form the equation:

So all you have to do is solve for x and substitute it into (100-2x) for the abundance of 184W
0
#9
(Original post by dxnixl)
Remember that: each isotope has the same number of electrons despite differing number of neutrons. electron configuration determines chemical property.

The question needs you to do a little bit of algebra (or well Id do it like that):

We can assume that the abundance of 182 and 183 is x and x respectively (due to the 1:1 ratio). Therefore the abundance of 184 would be (100-2x). Remember that:

182W abundance + 183W abundance + 184W abundance would equal to 100 (as a percentage).

To figure out abundance of one isotope we do (Isotopic mass X percentage abundance). Algebraically we can form the equation:

So all you have to do is solve for x and substitute it into (100-2x) for the abundance of 184W
Thank youuu
0
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