For the following calculations SHOW ALL WORK!! (6 points each) 7. The half- life of molybdenum-99 is 67.0 hours. How much of a 1.000 gram sample
remains after 335 hours.

8. Determine the average atomic mass of gallium if 60.00% of its atoms have a mass of
68.926 amu and 40.00% have a mass of 70.925 amu.

i think its 100.

hope this !

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally