the half-life of tritium, or hydrogen-3, is 12.32 years. after about 37 years, how much of a sample of tritium will remain unchanged? a)1/8    b)1/4  c)1/3  d)1/2

The correct option is A) 1/8

half-life of tritium, or hydrogen-3, is 12.32 years.      

After about 37 years,

= 37/12.32

= 3

means 3 half lives.

sample of tritium that will remain unchanged will be:

= 1/2^no.of half lives

= 1/2³

= 1/2 x 1/2 x 1/2 = 1/8

1/8 remains back

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.