Technetium-104 has a half-life of 18.0 minutes. How much of a 165.0 g sample remains after 36.0 minutes?

41.25g

Explanation:

Given parameters:

Half-life of Technetium - 104  = 18minutes

Mass = 165g

Unknown:

Mass of sample remaining after 36minutes = ?

Solution:

The half-life of a radioactive element is the time taken for half of the element to decay;

Now;

                Start           First half life              Second half-life

Time          0                      18min                        36min

 Mass       165g                 82.5g                        41.25g

answer

i think the answer is a) as air pressure in an area increases, the density of the gas particles in that area decreases.

hope it

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).