Simplifying equation variables I have two emissions equations I am working with that are giving me problems. The first problem I was able to solve my self, the second I have not and am not sure if it is possible. 
Emission Equation 1
I have an emission equation that has 1 changing variable, concentration, which changes depending on the chemical being measured. To get total emissions each chemical is calculated separately and the results are added together. 
A x B x (concentration 1) x C = emission 1
A x B x (concentration 2) x C = emission 2
Total emissions = emission 1 + emission 2
Since the rest of the equation is constant for what I am doing I was able to add up all the concentrations and enter that as one variable and get the same answer as if I had done a separate equation for each chemical and then add up the results. (Keeping this as one equation simplifies other things down the road in the program I’m using)
A x B x (concentration 1 + concentration 2) x C = total emissions
Emission equation 2
Now, calculating for different process emissions, I have an equation with 2 changing variables, concentration and molecular weight that change depending on the chemical being calculated for. The rest of the equation is constant for what I am doing.
A x B x (concentration 1) x (Molecular Weight 1) x C = emission 1
A x B x (concentration 2) x (Molecular Weight 2) x C = emission 2
Total emissions = emission 1 + emission 2
Is it possible to manipulate my 2 variables so this can be calculated using 1 equation the way I did with my first problem? Some of the processes I am calculating for have 20+ chemicals to calculate for. Calculating for each one will be a time consuming hassel to maintain in the program I’m using. I would appreciate any insight. 
Thanks!
 A: Assuming I understood your question correctly: yes.
First, you'll want to rewrite the following:

A x B x (concentration 1) x C = emission 1
  A x B x (concentration 2) x C = emission 2
  Total emissions = emission 1 + emission 2  

To

A x B x C x (concentration 1) = emission 1
  A x B x C x (concentration 2) = emission 2
  Total emissions = emission 1 + emission 2  

Then clearly

emission 1 + emission 2 = (A x B x C x (concentration 1)) + (A x B x C x (concentration 2))

and by distributivity:

emission 1 + emission 2 = (A x B x C) x (concentration 1 + concentration 2)

so 

Total emissions = (A x B x C) x (concentration 1 + concentration 2)


For the second part, it's more of the same.
First, rewrite:

A x B x (concentration 1) x (Molecular Weight 1) x C = emission 1
  A x B x (concentration 2) x (Molecular Weight 2) x C = emission 2  

To

A x B x C x (concentration 1) x (Molecular Weight 1) = emission 1
  A x B x C x (concentration 2) x (Molecular Weight 2) = emission 2  

Then 

emission 1 + emission 2 = (A x B x C x (concentration 1) x (Molecular Weight 1)) +
  $\phantom{ emission 1 + emission 2 = }$(A x B x C x (concentration 2) x (Molecular Weight 2))

So, like above, use distributivity to factor out the A B C:

emission 1 + emission 2 = (A x B x C) x ((concentration 1 x Molecular Weight 1) +
  $\phantom{emission 1 + emission 2 = (A x B x C) xfff }$ (concentration 2 x Molecular Weight 2))

The key here to remember is that in terms of multiplicativity, if you have $C + (A \times B)$, it's just the same as letting $X = A \times B$, so you get $C + X$. 
