calculate the atomic mass of copper if copper -63 is 69.17% abundant and copper-65 is 30.83% abundant.

Answer 1

To calculate the atomic mass of copper using the abundances of its isotopes, we can use the following formula:

$$\text{Atomic Mass}=(\text{abundance of Cu-63}\times \text{mass of Cu-63})+(\text{abundance of Cu-65}\times \text{mass of Cu-65})$$

Given:

• Abundance of Cu-63 = 69.17% = 0.6917 (as a fraction)
• Mass of Cu-63 = 63 amu
• Abundance of Cu-65 = 30.83% = 0.3083 (as a fraction)
• Mass of Cu-65 = 65 amu

Now we can substitute these values into the formula:

$$\text{Atomic Mass}=(0.6917\times 63)+(0.3083\times 65)$$

Calculating each part:

1. For Cu-63: $$0.6917\times 63=43.1211$$

2. For Cu-65: $$0.3083\times 65=20.0445$$

Adding these results together:

$$\text{Atomic Mass}=43.1211+20.0445=63.1656$$

Thus, the atomic mass of copper, based on the given isotopic abundances, is approximately 63.17 amu.