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Anonymous Poster #1

### Cubic Centimeter/Gal to PPM

08/28/2012 8:40 AM

Hi, please tell me how to convert 0.75cc of water/1 gal (US) of fuel into ppm.

I've calculated as below ways,

1) I've equated parts to m3 of volume

0.75cc/1 gal = 0.00000075m3/0.00379m3 = 1979m3/1000000 m3 = 1979ppm

2) But when i equate parts to grams, i'm getting,

0.75cc/1 gal = 0.00000075 m3 of water/ 0.00379 m3 of fuel = 750mg of water/3.05 kg of fuel = 245.9 mg/ kg = 245.9 ppm

Kindly correct me, how to convert volume / volume to ppm.

And what exactly PARTS means?

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#1

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 8:56 AM

The fuel and water have different densities, thus the different results.

Dilute solutions are generally expressed as mass fractions, or the mass of of one substance as a fraction of the mass of the entire mixture... Add the masses of the fuel and water together.

1,000 gram of water, 1,000,000 gram of fuel = 1,000/1,001,000 ≈ 999PPM

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#2

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 9:41 AM

"Parts-per notation is often used describing dilute solutions in chemistry, for instance, the relative abundance of dissolved minerals or pollutants in water. The unit "1 ppm" can be used for a mass fraction if a water-borne pollutant is present at one-millionth of a gram per gram of sample solution.

Similarly, parts-per notation is used also in physics and engineering to express the value of various proportional phenomena. For instance, a special metal alloy might expand 1.2 micrometers per meter of length for every degree Celsius and this would be expressed as "α = 1.2 ppm/°C." Parts-per notation is also employed to denote the change, stability, or uncertainty in measurements. For instance, the accuracy of land-survey distance measurements when using a laser rangefinder might be 1 millimeter per kilometer of distance; this could be expressed as "Accuracy = 1 ppm."[1]

Parts-per notations are all dimensionless quantities: in mathematical expressions, the units of measurement always cancel. In fractions like "2 nanometers per meter" (2 nm/m = 2 nano = 2 × 10−9 = 2 ppb = 2 × 0.000000001) so the quotients are pure-number coefficients with positive values less than 1. When parts-per notations, including the percent symbol (%), are used in regular prose (as opposed to mathematical expressions), they are still pure-number dimensionless quantities. However, they generally take the literal "parts per" meaning of a comparative ratio (e.g., "2 ppb" would generally be interpreted as "two parts in a billion parts").[2]

Parts-per notations may be expressed in terms of any unit of the same measure. For instance, the coefficient of thermal expansion of a certain brass alloy, α = 18.7 ppm/°C, may be expressed as 18.7 (µm/m)/°C, or as 18.7 (µin/in)/°C; the numeric value representing a relative proportion does not change with the adoption of a different unit of measure.[3] Similarly, a metering pump that injects a trace chemical into the main process line at the proportional flow rate Qp = 125 ppm, is doing so at a rate that may be expressed in a variety of volumetric units, including 125 µL/L, 125 µgal/gal, 125 cm3/m3, etc.

Ppm is also a measure of the chemical shift in nuclear magnetic resonance spectroscopy and represents difference of the frequency in parts per million from the reference frequency (signal)."

http://en.wikipedia.org/wiki/Parts-per_notation

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#3

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 11:32 AM

Please check these figures. They are from a Conversion Program I have.

0.75cc = 0.000198 of a US Gallon.

So divide 0.000198 by 1,000,000 = 198

So 0.75cc of a US Gallon = 198 ppm

Is it that easy?

I doubt it.

John

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#4
In reply to #3

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 11:42 AM

That's volume.

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#5
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### Re: Cubic Centimeter/Gal to PPM

08/28/2012 11:49 AM

Hi Doorman,

I thought we were talking cc's & US Gallons isn't that volume?

Best regards,

John

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#7
In reply to #5

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 12:03 PM

Jesw55, I am making a guess from our original post.

He said "Kindly correct me, how to convert volume / volume to ppm.", so I am assuming that mass fraction is what he is looking for. As you pointed out, he already has volumes of each, (cc and gallons) so that would be pretty simple.

As is the case so many times, the question lacks specificity. We will have to wait for our anonymous friend to return.

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#6

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 12:00 PM

[Edit - this was almost certainly explained in SolarEagle's post, but just to clarify...]

"And what exactly PARTS means?"

It means what it says - e.g. 1ppm (by volume) = 1cc (one part) in 1,000,000cc (one million parts), or 0.0001%.

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#8

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 1:00 PM

Why not just let the OP learn how to fish, instead of feeding him.

Online conversion of weights and measures, measurement ...

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#9

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 2:16 PM

And what exactly PARTS means?

Good question. There is not a standardized meaning: parts per million can be by volume or by mass. In mixing epoxy, it is common to mix 1 part of A with 2 parts of B (by volume). In more critical epoxy usages, it is not uncommon to mix 1 part of A with 1.95 parts B, by weight.

In all cases when "parts" is specified, the units must be the same -- i.e., either weight or volume. If neither is specified, weight is usually assumed... but you cannot be sure.

In any case, .75cc of water weighs .75 gram. The weight of a gallon of "fuel" cannot be determined without knowing what kind of fuel it is. We will assume petrol (average .75grams/cc) One US gallon is 3785 cc. So a gallon of petrol weighs .75 x 3785 grams = 2839 grams. .75/2839 = .000264 or 264 ppm.

Without having to think too hard, you can guess that petrol and gasoline are not dramatically different in density. So if you worked by volume, your number should still need to be somewhere close to 264 ppm (rather than one number being 8 times larger than the other, as your calculations show).

It's always helpful to make a rough guess to help ensure that you numbers are reasonable.

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#10
In reply to #9

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 2:29 PM

I'd always thought that "Gasoline" was the US word for UK "Petrol" (and, of course, vice versa). Does "petrol" have some other meaning the the US?

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#11
In reply to #10

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 4:06 PM

They have the same meaning to me, too.

Ken?

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#13
In reply to #11

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 8:50 PM

It took me a while to figure out what you were getting at here. I thought I'd written that petrol and water are not too far apart in density. I was using the word petrol instead of gasoline, because I sensed that the OP may be from outside the US. But, being easily confused, (and probably put right over the edge of sanity by using the less familiar word) I typed "gasoline" when I was thinking water. I can see that it would make my point pretty unclear.

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#12
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### Re: Cubic Centimeter/Gal to PPM

08/28/2012 8:44 PM

whoops...

you can guess that petrol and gasoline are not dramatically different in density

you can guess that petrol and water are not dramatically different in density

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#14
In reply to #9

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 11:44 PM

".75cc of water weighs .75 gram"

but .75cc of water weighs 0.75 milligrams

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#15

### Re: Cubic Centimeter/Gal to PPM

08/28/2012 11:52 PM

If you can accept that a mg/L is the same as a ppm then:

1 cc= 1 mL

For H2O

.75 cc = .75mg

1 US gal = 3.785 L

Thus .75 mg/3.785 L = 0.198 mg/L or 0.198 ppm

I just thought I would confuse the issue. The volume of gas is given and the weight of the water is the other known factor. You can ignore the weight of gas in this case and rest assured that the gas is contaminated with 0.198 mg/L of water. I think that is how you need to report the answer.

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#16
In reply to #15

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 12:17 AM

1cc of water at 4°C weighs 1 gram, not 1 mg.

1cc of water at 4°C is equal in volume to 1 ml.

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#19
In reply to #15

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 9:47 AM

Sorry K Fry and Lyn you are right. My answer should be 198 mg/L.

1cc=1000mL

0.75 cc=750mg H2O and 750mg/3.785L = 198 mg/L

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#22
In reply to #19

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 10:48 AM

1cc=1mL, not 1,000mL.

1,000mL= 1 liter.

Don't you hate metrics?

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#24
In reply to #22

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 10:57 AM

What would you prefer instead? Cubic cubits? Rods, poles and perches? Bushels and tuns? .

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#25
In reply to #22

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 11:08 AM

It is a lot easier than American units....mostly. But I got caught with my fingers in the door again; 1 cc= 1gram =1000mg. Answer is still the same. Grew up with British but we switched to metric in the 60s but I was already finished high school. British/American/metric/SI at the same time, damn right I was a confused young man. Oh hell, back to the couch. Try this one:

Einstein, Newton and Pascal decide to play hide and seek. Einstein is it, closes his eyes, counts to 10 then opens them.

Pascal is no where to be seen.

Newton is sitting right in front of Einstein, with a piece of chalk in his hand. He's sitting in a box drawn on the ground, a meter to a side.

Einstein says "Newton, you're terrible, I've found you!"

Newton says "No no, Einy. You've found one Newton per square meter. You've found Pascal!"

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#17

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 2:39 AM

Thank you sirs for all your replies. One correction in my original post is

"1) I've equated parts to m3 of volume

0.75cc/1 gal = 0.00000075m3/0.00379m3 = 197.9m3/1000000 m3 = 197.9ppm"

Not

"1979m3/1000000 m3 = 1979ppm" which is wrong

Very sorry for the mistake.

I'm getting 197.9ppm (by volume) and 245.9ppm (by mass), Im dealing with Jet A1 fuel of density 804 kg/m3 at 25 deg C. Around 200kg/m3 difference is there between water and fuel, is that making a difference of 245.9-197.9 = 48 ppm?

Then while mentioning ppm should we mention (by volume) or (by gram)?

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#18
In reply to #17

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 7:25 AM

Since you are dealing with the stuff, you should be able to get the answer from a certified testing lab!

Both answers are correct if you state By mass or by volume when you submit. You need to know what is the standard norme.

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#20
In reply to #17

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 10:26 AM

"... is that making a difference of 245.9-197.9 = 48 ppm?"

Yes, 245.9 minus 197.9 = 48.

No, 245.9 PPM(v/v) minus 197.0 PPM(m/m) 48 PPM. These two ratios have no direct relationship to each other in this context.

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#21
In reply to #20

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 10:43 AM

Ooops! Too late to edit.

I mixed up the PPM volume and PPM mass values. Sorry.

Should be: 245.9 PPM(m/m) minus 197.0 PPM(v/v) 48 PPM.

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#23
In reply to #20

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 10:54 AM

245.9 is actually m/m and 197 is v/v. I hope the OP realizes how lucky he is to have you and me keeping him on his toes by throwing in the occasional "accidental" typo.

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#27
In reply to #17

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 11:37 AM

I'm getting 197.9ppm (by volume) and 245.9ppm (by mass), Im dealing with Jet A1 fuel of density 804 kg/m3 at 25 deg C. Around 200kg/m3 difference is there between water and fuel, is that making a difference of 245.9-197.9 = 48 ppm?

Yes, if you are asking if the difference in the PPM values (m/m vs v/v) is because of the difference in densities of the fluids. 198 is 80% of 246, just as jet fuel is 80% as dense as water.

Jet fuel and water mix, to some extent, so one spec has to do with how easily water separates out of jet fuel. If you were the manufacturer, you would need a much more thorough understanding of the degree to which the fluids mix and how this is measured.

Mass vs volume can be potentially confusing when dealing with liquids (or particulate solids for that matter). When you mix 50 ml of water and 50 ml of ethanol, you get 96 ml of mixture. (Mix one liter of gravel and one liter of sand, and you get 1.5 liters of the mixture.) You can see that things could become complicated.

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#26

### Re: Cubic Centimeter/Gal to PPM

08/29/2012 11:21 AM

0.75cc/(3.785 [L/Gal]*1,000 [cc/L]*1,000,000)=198 ppm

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#28

### Re: Cubic Centimeter/Gal to PPM

09/11/2012 7:02 AM

Sirs,

Thanks a lot for all your replies. I got my doubt clarified.

Thanks for spending your valuable time for me.