M&M Isotope Lab Answer Key

Question: isotopes are

Answer: atoms of the same chemical element, each having a different mass number (neutrons).

Question: Isotopes differ in _____________ ______________ but never in ____________ ____________

Answer: mass number, atomic number

Question: the m&ms represent

Answer: atoms

Question: the purpose of this lab is

Answer: to calculate the average atomic mass using m&m’s and to observe the difference between isotopes.

Question: isotope #1

Answer: plain m&ms

Question: isotope #2

Answer: peanut m&ms

Question: average mass=

Answer: total mass/ # of m&ms

Question: % abundance=

Answer: # of each type of m&m/ total # of all m&ms x 100

Question: average atomic mass=

Answer: (mass of isotope 1)(% abundance) + (mass of isotope 2)(% abundance)…/100

Question: why is it important to zero out the paper towel when weighing the mass of the m&ms

Answer: the paper towel could add weight to the calculations