So what we know:
-Atomic Mass = Protons + Neutrons
-Atomic Number is the number of protons
Magnesium's atomic number is 12, so the natural occurring isotope for magnesium is Mg-12 (12 protons and 12 neutrons). Added up we have an atomic mass of 24 amu. Which means if we added one neutron in Mg-13, our atomic mass would be 25 amu.
We can use the equation:
(amu of isotope 1)x + (amu of isotop 2)(x-1) = Average atomic mass
where isotope 1 is the fractional abundance we're solving for.
Plugged in it looks like this:
24x + 25(1-x) = 24.3
Now to solve for x:
24x + 25 - 25x = 24.3
-x + 25 = 24.3
-x = -.7
x = .7
So in this case, the fractional abundance of Mg-12 would be .7, or 70%.<span />
Answer: Volume occupied by given neon sample at standard condition is 123.84 L.
Explanation:
Given: 
= 105 L, 
, 
= 985 torr
At standard conditions,
= 273 K, 
= 760 K, 
= ?
Formula used to calculate the volume is as follows.
Substitute the values into above formula as follows.
Thus, we can conclude that volume occupied by given neon sample at standard condition is 123.84 L.
C. The reaction goes from one of less moles to more causing it to be more disordered and therefore have a positive change in s
