Chap 3 Lab: Atomic Mass of Beanium Name: ___________________________________ Introduction: Write a paragraph defining what an isotope is and what effect the number of neutrons has on the atom. Include a discussion of what “percent abundance” means. Purpose: To analyze the isotopes of beanium and to calculate its atomic mass. Procedure: 1) Obtain a sample of beanium isotopes by scooping up a beaker full of beans from the bean container. 2) Separate the beans by isotope and count them. Record in “# of beans” section of data table. 3) For each isotope sample of beanium, determine its total mass using the balance. Record in table. 4) For each isotope, calculate the average mass of one bean by dividing the total mass of that isotope by the number of beans of that isotope. Record in table. 5) For each isotope, calculate its percent abundance by dividing the number of beans in each isotope by the total number of beans. 6) Calculate the average atomic mass of beanium by first multiplying each isotope’s average mass by its percent abundance and then adding these values together. Data: # of beans Total mass of beans Average mass of % Abundance of ISOTOPE (atoms) (grams) 1 bean (grams) each type of bean White Black Pinto Small Brown Kidney Total number of bean element atoms in cup = _________ Calculations: (you must show work) Determine the average atomic mass of beanium. Remember the equation for average atomic mass: Atomic Mass = (% abundance A)(mass A) + (% abundance B)(mass B) + …. Conclusions: (write in complete sentences) 1) Why is it important to calculate a weighted average for atomic mass and not just a normal average? 2) Explain the differences between the atomic mass of your beanium sample and that of your neighbor group. Explain why the difference would be smaller if larger samples were used.