Boron has two stable isotopes 5 B 10 and 5 B 11. Their respective masses are 10.01294 u and 11.00931 u and the atomic mass of boron is 10.811 u. The abundance of 5 B 10 and 5 B 11 are respectively nearing to

Question

Boron has two stable isotopes 5 B 10 and 5 B 11. Their respective masses are 10.01294 u and 11.00931 u and the atomic mass of boron is 10.811 u. The abundance of 5 B 10 and 5 B 11 are respectively nearing to (A) 50 %, 50 % (B) 20 %, 80 % (C) 25 %, 75 % (D) 5 %, 95 %

Tardigrade Admin · Accepted Answer

Let the percentage of 510 B in sample be x. Then, percentage of 511 B is (100-x). So, using formula of average atomic masses of isotopes, 10.811=(10.01294 × x+11.00931(100-x)/100) ⇒ 1081.1=1100.931-0.99637 x ⇒ 0.99637 x=19.831 ∴ x=(19.831/0.99637)=19.3 ≈ 20 %

Q. Boron has two stable isotopes $_{5} B^{10}$ and $_{5} B^{11}$ . Their respective masses are $10.01294 u$ and $11.00931 u$ and the atomic mass of boron is $10.811 u$ . The abundance of $_{5} B^{10}$ and $_{5} B^{11}$ are respectively nearing to

$50%, 50%$

$20%, 80%$

$25%, 75%$

$5%, 95%$

Q. Boron has two stable isotopes 5​B10 and 5​B11. Their respective masses are 10.01294u and 11.00931u and the atomic mass of boron is 10.811u. The abundance of 5​B10 and 5​B11 are respectively nearing to

50%,50%

20%,80%

25%,75%

5%,95%

Let the percentage of 510​B in sample be x. Then, percentage of 511​B is (100−x). So, using formula of average atomic masses of isotopes, 10.811=10010.01294×x+11.00931(100−x)​ ⇒1081.1=1100.931−0.99637x ⇒0.99637x=19.831 ∴x=0.9963719.831​=19.3≈20%

Q. Boron has two stable isotopes $_{5} B^{10}$ and $_{5} B^{11}$ . Their respective masses are $10.01294 u$ and $11.00931 u$ and the atomic mass of boron is $10.811 u$ . The abundance of $_{5} B^{10}$ and $_{5} B^{11}$ are respectively nearing to

$50%, 50%$

$20%, 80%$

$25%, 75%$

$5%, 95%$