Question

What is the "average atomic mass" of this set of pennies.

(can you guys also include a formula on how i can solve future problems like this, please.)

Answer 1

A. 2.74g is the correct answer

Step-by-step explanation:

Greetings!

`average \: mass = ((mass \: pre - 1982 * abundance) + (mass \: post - 1982 * abundance)/(100 ) \\ ave = ( (3.1g * 40.0) + (2.5g * 60.0))/(100) \\ ave = (124 + 150)/(100) \\ ave = (274)/(10) = 2.74g`

where, the sum of abundance always have to be 100%

Thus, 40.0 +60.0= 100.0