Question

9 what is the step 3 of how to calculate average atomic mass? (1 point) multiply each decimal by its mass number. move the decimal two places to the left in each percent abundance. add up all the masses. round to two decimal places and label your answer as \amu\. subtract the mass number from each percent abundance.

Explanation:

To calculate average atomic mass, first convert percent - abundances to decimals (by moving decimal two places left). Then multiply each decimal by its mass number. Finally, add up all the products, round to two decimal places and label as "amu". So the third step is adding up all the masses, rounding and labeling.

Answer:

Add up all the masses. Round to two decimal places and label your answer as "amu".