The so-called "20 lb propane bottle" is, I believe, a rather 'nominal' figure.
I'm looking for some rather exact figures. How many gallons of propane does this 20 lb bottle hold? How much does propane weigh per gallon?
I've seen these _EXACT_ figures posted where I get my bottles filled, but I cannot go to that place within next week or so........
Thank you.... Lee Carkenord
Try:
Fluid Temperature (oC)Specific Gravity
Propane- 40 .585
The specifuc gravity of propane is 0.585. Multiply that times 8.33 (weight of one gallon of water) and you get 4.87305 pounds as the weight of a gallon of propane. Divide that into 20 and you get 4.1+ gallons.
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except that they don't fill propane bottles. depending upon the type, it should be close to 80% is considered full.
Are you looking for what the volume of the container is? or what the volume of the propane would be in open air? 'cause the amount of space that the propane takes up is exactly equal to the volume of the bottle, no matter how much propane in in there.
But anyway: The Molar weight of Propane is 44.1 grams per mole. Thus, one mole of propane weight 44.1 grams, and occupies 22.4 liters at STP.
20 pounds is a bit over 9000 grams, and therefore 203190 liters, or 53621 gallons. Again, at STP. At room temperature, instead of freezing, that would be around 10% bigger. But I would have expected propane to be measured in cubic feet, not gallons, and that figure should be roughly 7100+ cf.
Your ability to do math is impressive, but you did not answer the real question. How much propane is in a 20 pound thank so he can figure the cost or how long it will last. 7100 cubic feet is a rather big tank to have for a grill don't you think?
Those bottles are usually referred to as 5 gallon. However, with the new valve you are fortunate to get 4.25 gallons.
Do you mean that one used to be able to get more than 20lbs of propane while paying for only 20lb, or that one could get more than 20lb but paid for the extra?
No. You no longer get 20 pounds. If you have it filled they usually charge you by the weight or number of gallons that are actually put in the tank. Before the new safety valve some would fill the tank too full. I have had some that started blowing off gas through the safety valve when they started to get warm.
I have two of them on my trailer and the difference in how long they last is noticeable.
Several sites about it:
Propane has 91,044 Btu per gallon liquid.
OTOH, the 20 pound figure is the weight of the empty tank, not the amountof gas in the tank. IIRC, that is about 16 pounds, but I don't know for fact. Here is some information:
According to:
I think those tanks could hold more than 5 gallons, but as I remember, by law they were not supposed to be fille more than to 80% of capacity. The new valves assure that.
The tank weighs right about 17 pounds. I weighed a full tank a while ago and I think it was about 37 pounds.
Just bought a new grill and new tank -- empty. When filled it had taken just over four gallons. I was surprised because, with the old valves, they usually would get about five gallons in.
Holy Cow - 53.6 thousand gallons That's an impressive number when you pause to think about helium balloons that look to be about a one gallon size. What's the molar weight of Helium, # per liter? Wonder how many gallons is in the standard bernzomatic.
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