If 20.g of a radioactive isotope are present at 1: 00 pm and 5.0g remain at 2: 00 pm, what is the half life of the isotope?

The  half  life  of   the  isotope  is  calculated  as  follows

    the  time  difference  =  2.00- 1.00 =  1 hour(60min)

if  20  g  decay  in  1 hour (60min)  and  5  grams  remains  then the  mass  that  decay  =  20-5 = 15   grams

  the  half  life  is  time  required  for  a quantity  to  reduce  to  half  its  initial  value

and  if the  initial   concentration  = 20g then  the   half  =  20/2  =  10g

then  time  =    10g   x  60min/15g  = 40 min

Ithe undersigned only for use your own email and delete any and copies and of the itself and to be there is a good timewhat does a decrease in temperature indicate about the molecules in a sample of liquid water? decreased chemical energy of the moleculesdecreased kinetic energy of the moleculesincreased chemical energy of the moleculesincreased kinetic energy of the moleculeshow does a sample of helium at 15 â°c compare to a sample of helium at 215 k? the helium at 15 â°c has a higher average kinetic energy than the sample at 215 k.the helium at 15 â°c has lower nuclear energy than the sample at 215 k.the helium at 15 â°c has slower-moving atoms than the sample at 215 k.the helium at 15 â°c has smaller atoms than the sample at 215 k.