Question

The table shows the amount of radioactive element remaining in a sample over a period of time.


Radioactive Decay Rate
Amount of Radioactive Sample
(grams) Time
(hours)
186.0 0
147.0 7
117.0 14
93.0 21
23.3 63


Part 1: What is the half-life of the element? Explain how you determined this.
Part 2: How long would it take 320 g of the sample to decay to 2.5 grams? Show your work or explain your answer.

Answer 1

the interval of time required for one-half

Answer 2

?

Answer 3

i mean i studied not alot

Answer 4

i dont understand the element part tho

Answer 5

oh

Answer 6

without that how do i determine the half life

Answer 7

cuz idk what element theyre referring to

Answer 8

part 1)

notice how the starting amount is 186.0g The half-life would be the amount of time it takes to decay by 1/2. One half of 186.0 is 93.0. Now look at the table, how long does it take to decay to 93.0g?

part 2)

if we think about the decay from 320g to 2.5g in terms of half-lives

320 ---> 160 ---> 80 ---> 40 ---> 20 ---> 10 ---> 5 --- > 2.5

it decays by half 7 times, so multiply the half life from part 1 by 7