Breakdown of Ces particules sont constituées de gaz.
être
to be
ce
this (before a noun)
de
of / from / any (in negative sentences) / about (concerning)
le gaz
the gas
Questions & Answers about Ces particules sont constituées de gaz.
Why do we use de instead of par in this passive sentence?
Verbs that describe a state, condition, or physical composition rather than a specific physical action take de instead of par in the passive voice. Since being made up of gas is a structural state, de is the correct choice here.
Why is there no article before gaz (such as du)?
When de indicates the raw material or substance something is made of in a general sense, it drops the definite article. It behaves like a preposition of material, so we simply say de gaz rather than du gaz (which would imply some specific gas).
Why does constituées end in -es?
The passive voice is formed with the auxiliary verb être and a past participle. With être, the past participle must always agree in gender and number with the subject. Since ces particules is feminine plural, constitué takes an extra -es.