The relative atomic mass is the weighted average mass of elements relative to 1/12th the mass of a 12-C atom.
Isotopes are atoms of the same element with different masses , in other words different numbers of neutrons.
Relative atomic mass =sum of (mass x percentage )
R.a.m = 62.9300 x 69.15% + 64.9200 x 30.85%
= 43.52 + 20.03
= 63.55 amu
Answer:
option A is correct answer
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
If ALL individuals of a species were not able to have offspring, then that species would eventually become extinct.
