If a sample of U−238U−238 initially contained 1.8×1018 atoms and was formed 5.6 billion years ago, how many U−238U−238 atoms does it contain today?

If a sample of U−238U−238 initially contained 1.8×1018 atoms and was formed 5.6 billion years ago,...
If a sample of U−238 initially contained 1.1×1018
atoms when the universe was formed 13.8 billion years ago, how many
U−238 atoms will it contain today?
How long will it take for 10% of the U-238 atoms in a sample of U-238 to decay? Express your answer using two significant figures Constants| Periodic Table The half-life for the radioactive decay of U - 238 is 4.5 billion years and is independent of initial concentration. t- 6.8x108 yr All attempts used;...
Halflife = 4.5 billion
years
Part B If a sample of U-238 initially contained 1.9x1018 atoms and was formed 3.8 billion years ago, how many U-238 atoms does it contain today? Express your answer using two significant figures. V AXO O ? atoms Submit Request Answer < Return to Assignment Provide Feedback
The half-life for the radioactive decay of U−238 is 4.5 billion years and is independent of initial concentration. How long will it take for 14 % of the U−238 atoms in a sample of U−238 to decay? If a sample of U−238 initially contained 1.4×1018 atoms and was formed 5.7 billion years ago, how many U−238 atoms does it contain today?
The half-life for the radioactive decay of U−238 is 4.5 billion years and is independent of initial concentration. a) How long will it take for 17 % of the U−238 atoms in a sample of U−238 to decay? Express your answer using two significant figures and in yrs b) If a sample of U−238 initially contained 1.8×1018 atoms and was formed 4.9 billion years ago, how many U−238 atoms does it contain today? Express your answer using two significant figures.
The half-life for the radioactive decay of U−238 is 4.5 billion years and is independent of initial concentration. If a sample of U−238 initially contained 1.2×1018 atoms and was formed 6.3 billion years ago, how many U−238 atoms does it contain today? Express your answer using two significant figures.
The half-life for the radioactive decay of U−238 is 4.5 billion years and is independent of initial concentration. 1.How long will it take for 10% of the U−238 atoms in a sample of U−238 to decay? 2.If a sample of U−238 initially contained 1.9×1018 atoms when the universe was formed 13.8 billion years ago, how many U−238 atoms will it contain today?
The half-life for the radioactive decay of U−238 is 4.5 billion years and is independent of initial concentration. Part A How long will it take for 14 % of the U−238 atoms in a sample of U−238 to decay? Express your answer using two significant figures. Part B If a sample of U−238 initially contained 1.4×1018 atoms and was formed 5.7 billion years ago, how many U−238 atoms does it contain today? Express your answer using two significant figures.
The half-life for the radioactive decay of U−238 is 4.5 billion years and is independent of initial concentration. Part A How long will it take for 20% of the U−238 atoms in a sample of U−238 to decay? Express your answer using two significant figures. Part B If a sample of U−238 initially contained 1.5×1018 atoms when the universe was formed 13.8 billion years ago, how many U−238 atoms will it contain today? Express your answer using two significant figures.
How long will it take for 18 %% of the U−238U−238 atoms in a sample of U−238U−238 to decay? Express your answer using two significant figures.
half life U-235 is 7.04x10^8 years
half life U-238 is 4.468 x10^9 years
3. One may assume that when U-238 was formed at the genesis of Earth, an equal amount of 235U was formed. Today the amount of 238U is 138 times the amount of 235U. How long a time ago did the genesis occur according to this assumption?