Question

Find a substance half-life in days. round your answer to the nearest tenths

Answer 1

Answer:

t=6.2days

Step-by-step explanation:

Find a substance half-life in days. round your answer to the nearest tenths

k value=0.1124

N0=33 grams

since the questions says the time it takes for the substance to reduce to half of its size. the initial mass doesn't matter

N=N0e^-kt

N/N0=e^-kt

take laperian log of both sides

Ln(N/N0)=-kt

Ln(0.5)=-0.1124t

-0.693=-0.1124t

t=6.16

t=6.2days

Note: Half life is the time it takes for a radioactive material to reduce to half of its size/mass.

Answer 2

A 33 gram sample has k value of .1124
(Actually I think the problem SHOULD be worded: A 33 gram sample has k value of -.1124/days)

See attached graphic:
Half-Life = ln (.5) / k
Half-Life = -.693147 / -.1124/days
Half-Life = 6.1667882562 days

Source:
http://www.1728.org/halflif2.htm