a sample of nitrogen contains 80% N14 atoms and 20% N15 atoms calculate the number of N15 atoms in 3kg of sample?
Answers
Answer:
refer the attachment for your answer ☝️
Explanation:
A sample of ammonia contains only H
1
and H
2
isotopes of hydrogen in 4:1 ratio and N
14
and N
15
isotopes of nitrogen in 3:1 ratio. How many neutrons are present in 1.785 mg ammonia?
(Answer in the order 10
18
) (N
A
=6×10
23
)
Medium
H
1
& H
2
→4:14x+x=100
x=20
↓ ↓
80% 20%
N
14
& N
15
→3:13x+x=100
x=25
↓ ↓
75% 25%
Relative Atomic mass of H=
100
80×1+20×2
=1.2 gm
Relative Atomic mass of N=
100
75×14+15×25
=14.25 gm
No. of neutrons in NH
3
=7.25+0.6=7.85
No. of neutrons in =
3(1.2)+14.25
1.785×10
−3
×6×10
23
×7.85
=
17.85
1.785×10
−3
×6×10
23
×7.85
=4.71×10
20
=471×10
18
0471
