Question

a hypothetical element E was discovered. it was found to exist in two isotopic form i.e 46E and 48E. the relative abundance of 46E is found to be 65% . what is the average atomic mass of element E

a) 47.0.
b)46.7
c)47.5
d)46.2

need a PROPER PROOF ​

Answer 1

Answer:

b 46.7

Explanation:

0.65 × 46 + 0.35 × 48

Answer 2

The average mass of element E is 46.7. So, option 'B' is correct.

Given:-

Mass of 1st isotope of E = 46E

Mass of 2nd isotope of E = 48E

Relative abundance of 1st isotope = 65%

To Find:-

The average mass of the element E.

Solution:-

We can simply calculate the average mass of element E by using these simple steps.

As

Mass of 1st isotope of E (m1) = 46E

Mass of 2nd isotope of E (m2) = 48E

Relative abundance of 1st isotope (x1) = 65%

Relative abundance of 2nd isotope (x2) = 100 - 65%

x2 = 35%

Average Atomic Mass (AAM) =?

Now, according to the formula of Relative mass,

$AAM = \frac{(m1 \times x1) + (m2 \times x2)}{100}$

On putting the values we get,

$AAM = \frac{(46 \times 65) +( 48 \times 35)}{100}$

$AAM = \frac{2990 + 1680}{100}$

$AAM = \frac{4670}{100}$

$AAM = 46.7$

Hence, The average mass of element E is 46.7. So, option 'B' is correct.

#SPJ2