Naturally occurring copper contains a mixture of 69.09% copper-63 (63.9298 amu) and 30.91% copper-65 (64.9278 amu). What is the average atomic mass of copper?
63.5474
0.6909*63.9298 + 0.3091*64.9278 = X
Note: Check your post. I think the 63.9298 should be 62.9298.
Isotopes
To find the average atomic mass of copper, we need to consider the percentages and the atomic masses of each isotope.
Step 1: Convert the percentages to decimal form.
The percentage of copper-63 is 69.09%, which is equal to 0.6909 as a decimal.
The percentage of copper-65 is 30.91%, which is equal to 0.3091 as a decimal.
Step 2: Calculate the weighted sum of the atomic masses.
Multiply the decimal percentages by their respective atomic masses and sum them up.
(0.6909 * 63.9298 amu) + (0.3091 * 64.9278 amu) = 44.1238 amu + 20.0449 amu = 64.1687 amu
Step 3: Round the average atomic mass.
The final step is to round the average atomic mass to the appropriate number of decimal places.
So, the average atomic mass of copper is approximately 64.169 amu.