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
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
I removed your incorrect answers to the math post. Please don't post answers for other students if you are not 100% sure and certainly not after a recognized tutor has replied. We remove incorrect and/or extraneous replies from other students.
To determine the mass number of the other isotope in the sample of antimony, you can use the information given in the question along with the concept of average atomic mass.
Here's how you can solve it step by step:
1. Assume you have 100 grams of the sample.
2. Determine the mass of 121Sb in the sample by multiplying 100 grams by the percentage of 121Sb (which is 60% or 0.6). This gives you 0.6 * 100 = 60 grams of 121Sb.
3. The remaining mass in the sample (since the total mass is 100 grams) must be the other isotope. So, subtract 60 grams (mass of 121Sb) from 100 grams to find the mass of the other isotope as 100 - 60 = 40 grams.
4. Now we need to set up an equation using the concept of average atomic mass. The average atomic mass is the weighted average of the isotopes, where the weight is given by the abundance of each isotope.
5. The average atomic mass is given as 121.8 (rounded to one decimal place).
6. We can set up the equation: (mass of 121Sb * abundance of 121Sb) + (mass of the other isotope * abundance of the other isotope) = average atomic mass.
7. Now plug in the values we know: (60 * 121) + (40 * X) = 121.8 * 100, where X represents the mass number of the other isotope.
8. Simplify the equation: 7260 + 40X = 12180.
9. Rearrange the equation to solve for X: 40X = 12180 - 7260.
10. Perform the subtraction: 40X = 4920.
11. Divide both sides by 40 to isolate X: X = 4920 / 40.
12. Calculate the value: X = 123.
Therefore, the mass number of the other isotope in the sample of antimony is 123.