A few questions about elements, densities, and specific energy.

[Emrys42]

http://en.wikipedia.org/wiki/Energy_density

This wiki page says the "specific energy" of Hydrogen is 123.

What is the specific energy of all the elements on the periodic table?

 

It also says the energy density of Hydrogen gas is 0.01005.

What is the most dense you will find Hydrogen in the largest possible gas giant(just before it would be considered a brown dwarf star? If your able to answer this for all the gases on the periodic table, even better.

 

http://www.periodictable.com/Properties/A/Density.html

This page says the density of Titanium is 4.507, it also says the density of Carbon in graphite form is 2.26 while the density of diamond(also carbon) is 3500.

What is the most dense titanium that could be found naturally occurring throughout the cosmos(that we know of)?

 

Thank you for any help you can offer.

If specific answers are difficult or impossible a close estimate would still be very helpful.

I misspoke on the first question. I am trying to get the specific energy of the gases or other burn able elements on the periodic table.

Also someone informed me that the density of titanium will mostly be the same once it leaves a star or black hole, is this correct?

[CaptainPanic]

In the case of hydrogen, they mean the "heat of combustion". And it is 123 MJ/kg hydrogen (you have to add the units, or else it means nothing!!).

I'm not gonna list all the elements... but if you look for "enthalpy of combustion", or "enthalpy of formation", then you can probably find quite a few of them.

 

I have no idea about titanium densities.

[swansont]

Densities will vary with pressure because of changes in volume; the relation that tells you this is the bulk modulus

http://en.wikipedia.org/wiki/Bulk_modulus

[Emrys42]

Thank you both, the more I learn about the enthalpy of combustion the more it seems a technologically advanced interstellar species would mostly only use hydrogen as a fuel if it was looking for the most enthalpy of combustion by volume and mass. If they weren't using a fuel they would(I assume of course) use fusion or fission engines. Does this seem accurate? If there are other substances then hydrogen they might want to use for fuel what do you think they would be and why?

[Enthalpy]

Combustion cannot bring a spacecraft to a remote star, because combustion rockets aren't good enough and stars are too far away.

 

If it's for science-fiction, take fission rockets instead

http://www.scienceforums.net/topic/78055-what-engines-and-fuels-would-interstellar-species-use-for-space-travel/#entry761035

or rather, just say "antimatter" and avoid giving too many details.