<span> First you need to know how many isotopes there are of silicon, and its average atomic units (look at periodic table). Then make up a system of equations to solve for it. Theres 3 stable silicon isotopes (28, 29, 30) so you will need to have 3 equations. You must be given the percent abundance of at least one of the isotopes to solve because here I can only see 2 equations (numbered down below) set x = percent abundance of si-28 y = percent abundance of si-29 z = percent abundance of si-30 since all of silicon atoms account for 100% of all silicon: x + y + z = 100% = 1 therefore: 1) x = 1 - y - z You also have 2) 28x + 29y + 30z = average atomic mass you can substitute x so that equation becomes: 28 (1 - y - z) + 29y + 30z = average atomic mass See how you have 2 variables here? You cant go on until you know the value of one isotope already or you have given a clue which you can derive the third equation</span>
The answer is mean,mode and median
Answer:
Composition of the mixture:
%
%
Composition of the vapor mixture:
%
%
Explanation:
If the ideal solution model is assumed, and the vapor phase is modeled as an ideal gas, the vapor pressure of a binary mixture with 
and 
molar fractions can be calculated as:
Where 
and 
are the vapor pressures of the pure compounds. A substance boils when its vapor pressure is equal to the pressure under it is; so it boils when 
. When the pressure is 0.60 atm, the vapor pressure has to be the same if the mixture is boiling, so:
With the same assumptions, the vapor mixture may obey to the equation:
, where P is the total pressure and y is the fraction in the vapor phase, so:
%
The fractions of B can be calculated according to the fact that the sum of the molar fractions is equal to 1.
