Question

Relative abundance of various isotopes of silicon is as si28=92.25% si29=4.65% and si30=3.10%.Calculate the average atomic mass of silicon

Answer 1

Answer:

Explanation:

Taking the atomic mass of every isotope -

isotope = Si-28  

amu =27.9769

abundance(%) =92.25

isotope = Si-29  

amu =28.9765

abundance(%) =4.65

isotope =Si-30  

amu =29.9738

abundance(%) = 3.10

Thus,

= 27.9769  × .9225 +  28.9765 × .0465  +  29.9738 × .0310  

Thus, this simplifies to:

= 25.7891  +  1.3648  +  0.9352

=  28.0891

The average atomic mass of silicon is 28.0891.

Answer 2

Answer:

Explanation:

Taking the atomic mass of every isotope -

isotope = Si-28

amu =27.9769

abundance(%) =92.25

isotope = Si-29

amu =28.9765

abundance(%) =4.65

isotope =Si-30

amu =29.9738

abundance(%) = 3.10

Thus,

= 27.9769 × .9225 + 28.9765 × .0465 + 29.9738 × .0310

Thus, this simplifies to:

= 25.7891 + 1.3648 + 0.9352

= 28.0891

The average atomic mass of silicon is 28.0891.