Este lugar é tranquilo para descansar.

Portuguese demonstratives often depend on “distance” (literal or conversational):

• este = “this (here/close to me / the one I’m introducing now)”
• esse = “that (near you / the one we just mentioned)”
• aquele = “that (over there / more distant)” So Este lugar typically implies the speaker is “pointing to” or presenting the place as close/relevant right now. In everyday Brazilian Portuguese, people frequently use esse where grammar books might prefer este, but este is still correct and common in more careful speech/writing.

Often you can choose either, depending on what you mean:

• é tranquilo (with ser) = the place is (in general/by nature) tranquil; a characteristic of it.
• está tranquilo (with estar) = it is tranquil right now (maybe today it’s calm, but not always). Both can translate as “is quiet,” but the implied permanence/temporariness differs.

Adjectives agree in gender/number with the noun they describe:

• lugar is masculine singular → tranquilo (masc. sing.) If it were plural: Estes lugares são tranquilos.
  If it were feminine: Esta área é tranquila.

Here para + infinitive expresses purpose: “for / in order to.”

• tranquilo para descansar = “quiet/peaceful for resting” / “a peaceful place to rest.” It’s one of the most common ways to express “(good) to do something” in Portuguese.

Meaning-wise, yes. pra is a very common contraction of para a and, in everyday speech, also of para before verbs:

• Formal/writing: para descansar
• Casual speech/texting: pra descansar In careful writing, stick with para.

Portuguese often uses para + infinitive where English uses “to + verb” or “for + -ing.” You can also use a noun sometimes:

• um lugar tranquilo para descansar (very natural)
• um lugar tranquilo para descanso (“for rest”) is possible but sounds more like “for休息”/“for the purpose of rest” and can feel more formal or fixed-phrase-like.

Yes, that’s possible. se can make the verb more impersonal/general (“for one to rest” / “to rest (here)”):

• ... para descansar = straightforward “to rest”
• ... para se descansar = “to rest (oneself) / for people to rest” (more generic/impersonal) In everyday Brazilian Portuguese, para descansar is more common and simpler.

No. Portuguese doesn’t need to repeat the noun or add an article here.
Este lugar é tranquilo para descansar is complete and natural.
You could add um if you want a slightly different structure, often with a nuance of classification:

• Este lugar é um lugar tranquilo para descansar (a bit repetitive)
• Better: Este lugar é um lugar tranquilo para descansar → usually shortened to Este lugar é tranquilo para descansar or Este lugar é um lugar tranquilo para descansar only if you’re contrasting categories.

You can, but it’s often redundant because Este lugar already implies “here/this place.”
Add aqui if you want emphasis:

• ... para descansar aqui = “to rest here (in this specific spot),” especially if other places exist nearby.

Put não before the verb:

• Este lugar não é tranquilo para descansar. = “This place isn’t peaceful to rest (in).” With estar:
• Este lugar não está tranquilo para descansar hoje. = “This place isn’t peaceful to rest in today.”

The most natural order is exactly as given: adjective + purpose phrase:

• é tranquilo para descansar You can front the purpose for emphasis, but it sounds more marked:
• Para descansar, este lugar é tranquilo. (emphasis on “for resting”)

Plural changes demonstrative, verb, and adjective:

• Estes lugares são tranquilos para descansar. (este → estes, é → são, tranquilo → tranquilos)