A SAMPLE OF ANTIMONY, Ar=121.8, WAS ANALYSED AND WAS FOUND TO CONSIST OF 60% OF 121Sb AND ONE OTHER ISOTOPE. DETERMINE THE MASS NUMBER OF THE OTHER ISOTOPE IN THE SAMPLE OF ANTIMONY.
please help I'm really stuck,
Chemistry - bobpursley Saturday, September 30, 2017 at 10:41am
assume you have 100 grams. It becomes the overused algebra candy mixture problem.
60*121+40*X=121.8*100
solve for x
Chemistry - Dannau Saturday, January 6, 2018 at 7:01am
Thats wrong. The answer is 123
Chemistry - 0oooooooo0 today at 6:35am
How do you get that though
As chemistry - 0oooooooo0 Thursday, March 1, 2018 at 6:37am
I read somewhere the right answer is 123 but dont know how to get it and I tried Bobpursley equations but go -151.05 so I think that working out is wrong. Please help someone
Chemistry - bobpursley Saturday, September 30, 2017 at 10:41am
assume you have 100 grams. It becomes the overused algebra candy mixture problem.
60*121+40*X=121.8*100
solve for x
I am just a bit miffed: Here is what I told you to do:
60*121+40*X=121.8*100
40x=12180-7260=4920
x=123
You need to do some introspection: what is going wrong with you? Is it math? Is it you have became addicted to getting answers handed to you? Something is seriously wrong, and only you can figure it out.
To determine the mass number of the other isotope in the sample of antimony, we can follow these steps:
1. Let's assume that the sample weighs 100 grams for simplicity.
2. We are given that 60% of the sample consists of the isotope with a mass number of 121 (121Sb). That means there are 60 grams of 121Sb in the sample.
3. We need to find the mass number (let's call it X) of the other isotope.
4. The remaining 40% of the sample (which is 40 grams) is made up of the other isotope.
5. The average atomic mass of the sample is given as 121.8 amu (Ar= 121.8). This value accounts for the presence of both isotopes.
6. We can set up the equation to solve for X:
(mass of isotope with mass number 121 * atomic mass of isotope with mass number 121) + (mass of isotope with mass number X * atomic mass of isotope with mass number X) = total mass of the sample * average atomic mass
(60 grams * 121 amu) + (40 grams * X amu) = 100 grams * 121.8 amu
7. Simplifying the equation:
7260 + 40X = 12180
8. Subtracting 7260 from both sides of the equation:
40X = 4920
9. Dividing both sides by 40:
X = 123
Therefore, the mass number of the other isotope in the sample of antimony is 123.