okay, so sodium-25 was to be used in an experiment, but it took 3.0 minutes to get the sodium from the reactor to the laboratory. If 5.0 mg of sodium was removed from the reactor, how many mg of sodium-25 were replaced in the reaction vessel 3.0 minutes later if the half-life of sodium 25 is 60 seconds?

Question

anonymous · Answer

simple chart for a problem like this
time      mass
0            5
60          2.5
120        1.25
180        0.625
240        0.3125
300        0.15625