I’m wondering if I could say:
Having a good energy density by weight, hydrogen was chosen among other alternatives for many reasons.
or should I say:
Hydrogen which has a good energy density by weight was chosen among other alternatives for many reasons.
With many thanks.
Why mention its energy density if it was evidently chosen for other reasons? That makes both sentences awkward.
Many thanks. Really, I’ve not thought about it. What a funny guy I’m.
By the way, what do we call these tools (which, who, where,…)? and where could I find a good article about them?
Those are relative and interrogative pronouns. You can google those terms, and find sites like THIS and THIS.