Answer:
26.56g
Explanation:
The half life of an isotope decay is the time transcurred when the initial amount of the isotope decays to the half of its amount.
For the problem, when 1 half life transcur, the sample has a mass of:
425g / 2 = 212.5g
When 2 half lives transcur:
212.5g / 2 = 106.25g
3 half lives:
106.25/2 = 53.13g
And the amount that is found after 4 half lives is:
53.13/2 =
<h3>26.56g</h3>
The answer to your question is : no.of moles of Si = 43/atomic mass of Si = 43/28.1 = 1.53
according to reaction 3 moles of Si gives 1 mole of Si3N4
so 1.53 mole of Si will give 1.53/3 = 0.51 mole of Si3N4
molar mass of Si3N4 = 140.28 g/mole
it means that 1 mole of Si3N4 = 140.28 g
so 0.51 mole of Si3N4 = 0.51 X 140.28 = 71.543 g
