# Standard litres to kg conversion for Hydrogen [closed]

When looking at hydrogen fuel tanks, they often give the capacity in terms of "standard litres". However, I can't find a definition of what this is.

I assumed this may mean a litre of hydrogen gas at room temperature? If so, is this at standard air pressure or is it compressed to a certain pressure? If so, what is this pressure?

I also thought perhaps it was a conversion to a litre of liquid hydrogen?

Or is it neither of these?

Is there a conversion between standard litres and kilograms for Hydrogen?

• Since 1982, STP is defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly $10^5$ Pa (100 kPa, 1 bar). At STP a mole of gas occupies 22.7 liters. A mole of hydrogen has a mass of 2.016 grams. Thus $8.88\times10^{-2}$ grams/liter. – MaxW Apr 8 at 15:18
• Are you talking about hydrogen fuel tanks for cars? or something else? – Mathew Mahindaratne Apr 8 at 18:55
• @MathewMahindaratne, it isn't specifically tanks for cars, although I guess this could be an application. It is merely that if I look at Hydrogen storage tanks on the internet, many companies define the capacity in terms of "standard litres" and I was just curious as to what the definition of one "standard litre" is. – PhysicsGuy123 Apr 8 at 19:49

2. As a liquid in dewars or tanks (stored at $$\pu{-253 ^{\circ}C}$$).
$$\begin{array}{|c|c|c|c|c|c|} \hline \textrm{Storage Technology} & \textrm{Weight} & \textrm{Volume} & \textrm{Average Cost} \\ \textrm{} & \textrm{(kWh/kg)} & \textrm{(kWh/L)} & \textrm{(USD/kWh)} \\ \hline \textrm{Chemical Hydrides} & 1.6 & 1.4 & 8 \\ \hline \textrm{Complex Metal Hydrides} & 0.8 & 0.6 & 16 \\ \hline \textrm{Liquid Hydrogen} & 2.0 & 1.6 & 6 \\ \hline \textrm{Compressed Gas (10,000-psi)} & 1.9 & 1.3 & 16 \\ \hline \end{array}$$