Base your answers to questions 62 through 65 on the information below and on your knowledge of chemistry. Some isotopes of potassium are K-37, K-39, K-40, K-41 and K-42. The Natural abundance and the atomic mass for the naturally occurring isotopes of potassium are shown in the table below. 62 Identify the decay mode of K-37 [1] 63 Complete the nuclear equation in your answer booklet for the decay of K-40 by writing a notation for the missing nuclide. [1] 64 Determine the fraction of an original sample of K-42 that remains unchanged after 24.72 hours. [1] Answer--> 1/4 Use table N Work not required 24.72h/12.36h= 2 half lives 1--> 1/2--> 1/4 |
65Show the correct numerical setup for calculating the atomic mass of potassium. [1] Answer--> __((93.26)(38.96))+((0.01)(39.96))+((6.73)(40.96))__
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or ((93.26)(0.3896))+((0.0001)(39.96))+((6.73)(0.4096)) |
on to Questions 66-68 |