Calculating liquid ingredients volume based on the ratio of ingredients by weight

[State of Flux]

Hi,

I'm not sure if I'm posting this in the right category. I don't know enough about maths to tell what kind of a problem I have. I'll do my best to describe the problem in a way that will be easy to understand but I'm pretty new at this so please forgive me if I accidentally make it unnecessarily complicated.

The Problem:

I want to make a flux remover recipe but the only information I have is the % of each liquid ingredient by weight. Since the liquid ingredients are different, they have different densities so I can't just apply the % to volume as it will give an incorrect mixture. I would like to be able to calculate the exact volume of each ingredient that I would need in order to make up a specific volume of the end mixture. If I say 1L of the solvent mixture for the example, that would be OK.

The information I have is:

Chemical Name	%(weight)	Density	1L Bottle Flux Remover (mL)
Ethyl acetate	63%	0.902 g/cm^3
Acetone	25%	0.7845 g/cm^3
IPA	12%	0.786 g/cm^3

I know that 1cc = 1mL.

Does that make sense? Also, I don't actually need to know the answer to this question. I made a batch based on the weight when I gave up trying to calculate what the volume should be but I still want to know the answer and how to figure it out.

Thanks for your attention

Alex

 

[Dr.Peterson]

Hi,

I'm not sure if I'm posting this in the right category. I don't know enough about maths to tell what kind of a problem I have. I'll do my best to describe the problem in a way that will be easy to understand but I'm pretty new at this so please forgive me if I accidentally make it unnecessarily complicated.

The Problem:

I want to make a flux remover recipe but the only information I have is the % of each liquid ingredient by weight. Since the liquid ingredients are different, they have different densities so I can't just apply the % to volume as it will give an incorrect mixture. I would like to be able to calculate the exact volume of each ingredient that I would need in order to make up a specific volume of the end mixture. If I say 1L of the solvent mixture for the example, that would be OK.

The information I have is:

Chemical Name	%(weight)	Density	1L Bottle Flux Remover (mL)
Ethyl acetate	63%	0.902 g/cm^3
Acetone	25%	0.7845 g/cm^3
IPA	12%	0.786 g/cm^3

I know that 1cc = 1mL.

Does that make sense? Also, I don't actually need to know the answer to this question. I made a batch based on the weight when I gave up trying to calculate what the volume should be but I still want to know the answer and how to figure it out.

Thanks for your attention

Alex

You could use algebra, but I'd do it more like this:

Ignore the desired volume at first.

Suppose we want 63 g EA, 25 g Acetone, and 12 g IPA. The volumes are found by dividing by the density: 63/0.902 = 69.8 cc EA; 25/0.7835 = 31.9 cc Acetone; 12/0.786 = 15.27 cc IPA. The total volume is 69.8+31.9+15.27 = 116.97 cc (mL).

Find what you have to multiply the total volume by to get your goal (e.g. 1000 mL), and just multiply each of the three volumes by that amount, to scale up the mixture.

 

[Denis]

"Out of the blue" example:

QTY %
0.5 20
0.3 30
0.2 40
-------
1.0 27

[20(.5) + 30(.3) + 40(.2)] / 1 = 27

 

[State of Flux]

You could use algebra, but I'd do it more like this:

Ignore the desired volume at first.

Suppose we want 63 g EA, 25 g Acetone, and 12 g IPA. The volumes are found by dividing by the density: 63/0.902 = 69.8 cc EA; 25/0.7835 = 31.9 cc Acetone; 12/0.786 = 15.27 cc IPA. The total volume is 69.8+31.9+15.27 = 116.97 cc (mL).

Find what you have to multiply the total volume by to get your goal (e.g. 1000 mL), and just multiply each of the three volumes by that amount, to scale up the mixture.

Hi Dr.Peterson,

I think I understand what you are saying. I used your example and this is what I ended up with:

Calculate liquid volume equal to 63g + 25g + 12g:
= (63/0.902) + (25/0.7845) + (12/0.786)
= 69.85 + 31.87 + 15.27
= 116.99 mL

Calculate multiplication factor to make 1L:
1000mL/116.99mL = 8.55

So to make 1L I need:
(69.85 x 8.55) + (31.87 x 8.55) + (15.27 x 8.55)
= 597.22 + 272.49 + 130.56
= 1000.27mL
= close enough

Thank you for the clear and concise instruction.

Alex

 

[State of Flux]

"Out of the blue" example:

QTY %
0.5 20
0.3 30
0.2 40
-------
1.0 27

[20(.5) + 30(.3) + 40(.2)] / 1 = 27

Hi Denis,

I don't understand your example. Sorry, I'm really bad at this.