Question

On a mission to a newly discovered planet, an astronaut finds copper abundances of 69.15 % for 63cu and 30.85 % for 65cu. what is the atomic mass of copper for this location? the mass of 63cu is 62.9300 amu . the mass of 65cu is 64.9200 amu .

Answer 1

The relative atomic mass is the weighted average mass of elements relative to 1/12th the mass of a 12-C atom.
Isotopes are atoms of the same element with different masses , in other words different numbers of neutrons.
Relative atomic mass =sum of (mass x percentage )
R.a.m = 62.9300 x 69.15% + 64.9200 x 30.85%
= 43.52 + 20.03
= 63.55 amu

Answer 2

The relative atomic mass of copper on a newly discovered planet is $\boxed{63.54{\text{ amu}}}$ .

Further explanation:

An atom is also written as $_{\text{Z}}^{\text{A}}{\text{X}}$ , where A is the atomic mass or mass number, Z is the atomic number, and X is the letter symbol of the element.

Isotopes:

Atoms of the same element with same value of atomic number but different value of mass numbers are called isotopes. Isotopes generally have the same number of protons but the number of neutrons is different.

$_{\mathbf{6}}^{{\mathbf{11}}}{\mathbf{C}}$  and $_{\mathbf{6}}^{{\mathbf{12}}}{\mathbf{C}}$  are examples of isotopes. Both are the atoms of the same element carbon. The mass number of $_{\mathbf{6}}^{{\mathbf{11}}}{\mathbf{C}}$  is 11 while that of  $_{\mathbf{6}}^{{\mathbf{12}}}{\mathbf{C}}$ is 12. But both of these have the same atomic number, i.e, 6.

Relative Atomic Mass:

It is defined as the average mass of an atom of the element compared to 1/12th of the mass of carbon-12 atom. It is represented by ${{\text{A}}_{\text{r}}}$ . The formula to calculate the relative atomic mass of an element is as follows:

${{\text{A}}_{\text{r}}} = \frac{{\sum {\left\{{\left({{\text{Relative isotopic mass}}}\right)\left({{\text{\% abundance}}}\right)}\right\}}}}{{100}}$

Here,

${{\text{A}}_{\text{r}}}$  is the relative atomic mass.

It is given that copper (Cu) exists in two isotopic forms, one is 63 Cu, and the other is 65 Cu. So the relative atomic mass of Cu is calculated as follows:

${{\text{A}}_{\text{r}}}{\text{ of Cu}}=\frac{{\left[\begin{gathered}\left({{\text{Mass of 63 Cu}}}\right)\left({{\text{\% abundance of 63 Cu}}}\right)+\hfill\\\left({{\text{Mass of 65 Cu}}}\right)\left({{\text{\% abundance of 65 Cu}}}\right)\hfill\\\end{gathered}\right]}}{{100}}$                       …… (1)

The mass of 63 Cu is 62.9300 amu.

The percentage abundance of 63 Cu is 69.15 %.

The mass of 65 Cu is 64.9200 amu.

The percentage abundance of 65 Cu is 30.85 %.

Substitute these values in equation (1).

$\begin{aligned}{{\text{A}}_{\text{r}}}{\text{ of Cu}}&=\frac{{\left[{\left( {{\text{62}}{\text{.9300 amu}}}\right)\left({{\text{69}}{\text{.15}}}\right)+\left({{\text{64}}{\text{.9200 amu}}}\right)\left({{\text{30}}{\text{.85}}}\right)}\right]}}{{100}}\\&=\frac{{{\text{4351}}{\text{.6095 amu}}+{\text{2002}}{\text{.782 amu}}}}{{100}}\\&={\text{63}}{\text{.543915 amu}}\\&\approx{\text{63}}{\text{.54 amu}}\\\end{aligned}$

So the relative atomic mass of copper on a newly discovered planet is 63.54 amu.

Learn more:

1. Calculate the moles of chlorine in 8 moles of carbon tetrachloride: brainly.com/question/3064603

2. Calculate the moles of ions in the solution: brainly.com/question/5950133

Answer details:

Grade: Middle School

Subject: Chemistry

Chapter: Mole Concept  

Keywords: percentage abundance, 63 Cu, 65 Cu, 62.9300 amu, 64.9200 amu, 30.85 %, 69.15 %, 63.54 amu, copper, isotopes, carbon-12, Ar, Cu.