# 5 gallons of gasoline verses 15lbs of propane. Which has the higher energy?

This one should be simple for the “DOPE”. Need Answer fast and HI OPAL!

114,000 BTUs/gallon gasoline = 570,000 btu total
21,500 BTU/pound of propane =315,000 btu total

Here is a spreadsheet I put together that compares energy densities of various things.

Wow this chart instantly shows why gasoline is the good stuff.

Also why LNG conversion of vehicles is possible and practical in areas of the world where natural gas is much cheaper than gasoline.

Or is taxed at a much lower rate.

An interesting exercise in trivia is to compare the energy density of gasoline to that of dynamite.

The answer - which many find surprising - is that gasoline has more than 6 times the energy of the same mass of dynamite. So. for example, it would require more than 35 lbs of dynamite to match the energy in a gallon of gasoline.

It’s fair to note that to liberate the gasoline’s energy requires a considerable mass of oxygen, whereas the dynamite includes its own oxidizer.

The stoichiometric ratio for air and gasoline is about 14.7 pounds of air for one pound of gasoline. But air is about 20% oxygen, so it’s more like 3 pounds of oxygen for one pound of gasoline. This means the energy density of a stoichiometric gasoline-oxygen mixture is only about 1.5 times that of dynamite.

I suspect if you had a blend of gasoline and LO2, it might have an ability to detonate with a violence comparable to that of dynamite.

it would definitely detonate.

It would definitely go boom. But “detonate” is a technical term with a precise meaning that might or might not apply here.

LOX is something I fear the most. In Air-separation plants, LOX spilled on tar roads can cause an explosion. Here is a video of a professor lighting a charcoal grill with LOX Lighting a charcoal grill with liquid oxygen - YouTube
And the human body is just fuel to LOX. Many humans have worked around Air Separation plant (especially oxygen vents), then gone outside the plant for a smoke. Oxygen gets absorbed into their clothes and burns rapidly when they use the lighter.

This old (some may say funny) video from the US Navy shows the dangers of LOX (alert : graphic depiction at the end. Man From LOX - YouTube

I think many things that deflagrate when mixed with air absolutely will detonate (in the true technical sense) when mixed with pure O2. I can’t state authoritatively that a gasoline/LO2 blend will detonate, but I think it’s highly probable.

That’d be George Goble. I just mentioned him in another thread elsewhere on the Dope. He was made famous in one of Dave Barry’s columns in the mid-90s. One of the fun facts that stood out in that article was the importance of topping the pile of charcoal with a lit cigarette before pouring on the LO2; Goble said that a charcoal briquette soaked in LO2 had the explosive potential of a stick of dynamite, which meant that you wanted the ignition source to be present first.