17htodd
Answered

Copper exists in nature as two isotopes. The atomic masses and relative abundance of these isotopes is given in the table. What is the average atomic mass of copper?





A62.93 amu



B63.55 amu



C63.935 amu



D64.94 amu



E127.87 amu

Verified Answer :

W0lf93

The correct answer should be B) 63.55. That's because the most precise number is 63.546, but you would write 55 because 46 is rounded that way in the equation. The others are a bit higher, while E is a completely different element, Iodine. This isn't the most precise piece of data because in reality there would be a slight differentiation of +- 0,003u

PBCHEM

Answer : Option B) 63.55 amu

Explanation : To find the average atomic weight of the two isotopes of copper that exist in nature we can use the below formula;

Average atomic mass = ∑ (isotope(s) x abundance)

Therefore, we have the given values of atomic masses of two copper isotopes are
62.93 u and 64.93 u, respectively. They have natural abundance as 0.692 and 0.368, respectively,

On substituting the above values, we get,

Average atomic mass = (62.93 x 0.692) isotope 1 of Cu + (64.93 x 0.308) isotope 2 of Cu

Average atomic mass = 43.54 + 19.99 = 63.538 ~ 63.55

Therefore, the average atomic mass of Cu will be 63.55 amu.

View image PBCHEM

Related Questions