The half-life of Plutonium-23 is 30 min. How much of a 1500 mg sample will be left 5 hours from now?

Half life means exactly 1/2 of what's left decays

example

if yo has 16grams

if half life is 1 hour, after 1 hour, 8g is left

after another hour, 4g is left

after another your, 2g is left

etc

so find how many half lifes have elapes

so

the amount left after n halflives when you start with P amount is

A=P (1/2) ^n

5hr=60*5=300mins

300/30=10

10 half lifves

P=1500

n=10

A=1500 (1/2) ^10

A=375/256

A≈1.46484g

about 1.5g left