Chaque spectatrice écoute le violon en silence et applaudit à la fin du concert.

In French, chaque is always followed by a singular noun and takes a singular verb, even though it refers to more than one person.

• chaque spectatrice écoute… → literally “each spectator listens…”
• The verbs écoute and applaudit are in the 3rd person singular because the grammatical subject is singular.

If you want a clearly plural subject, you would change it:

• Toutes les spectatrices écoutent le violon en silence et applaudissent à la fin du concert.
  (Here both the noun and the verbs are plural.)

French normally marks gender on nouns referring to people:

• un spectateur = a (male) spectator
• une spectatrice = a (female) spectator

Using chaque spectatrice implies you are speaking specifically about female spectators.

If you mean:

• only men: Chaque spectateur écoute…
• a mixed or unspecified group: you normally use the masculine plural:
  • Tous les spectateurs écoutent le violon…
  • or more neutrally: Le public écoute le violon… (the audience)

Both refer to all the spectators, but the nuance is slightly different:

• chaque spectatrice: distributive idea, focusing on individuals
  • “each spectator, individually, listens and applauds”
• toutes les spectatrices: collective idea
  • “all the spectators as a group listen and applaud”

Grammatically:

• chaque spectatrice écoute / applaudit (singular)
• toutes les spectatrices écoutent / applaudissent (plural)

In French, écouter is a direct transitive verb: it takes a direct object with no preposition.

• écouter quelque chose / quelqu’un
  • écouter le violon
  • écouter la radio
  • écouter son ami

So you must not say écouter à or écouter à le violon.
The English “to” in “listen to” simply has no equivalent here.

You can say entendre le violon, but it doesn’t mean the same thing.

• écouter = to listen (actively, on purpose)
• entendre = to hear (passively, without necessarily trying)

So:

• Chaque spectatrice écoute le violon… → they are paying attention to the violin.
• Chaque spectatrice entend le violon… → they can hear the violin (it is audible), but we do not emphasize attention.

Here le violon is a direct object with the definite article le:

• écouter le violon = listen to the violin (the violin music being played)

Compare with other common structures:

• jouer du violon = to play the violin
  With jouer
  • instrument, French usually uses de + article:
    • du piano, de la guitare, du violon
• au violon is rare and would usually mean something like “at/on the violin” only in special contexts (for example, assigning someone to the violin part in an orchestra), not simply “listening to violin music”.

So for this sentence, écouter le violon is the natural choice.

Yes, en silence means roughly “in silence / silently”.

Grammar-wise:

• en
  • noun (silence) forms an adverbial phrase:
    • écoute le violon en silence = “listens to the violin in silence”

You could also say:

• écoute le violon silencieusement (with the adverb silencieusement)

But en silence is much more common and more natural in everyday French.

Yes, French allows some flexibility in where you put adverbial phrases like en silence. All of these are possible:

• Chaque spectatrice écoute le violon en silence et applaudit à la fin du concert.
  (neutral, very natural)
• Chaque spectatrice, en silence, écoute le violon et applaudit à la fin du concert.
  (slight emphasis on the silence)
• En silence, chaque spectatrice écoute le violon et applaudit à la fin du concert.
  (stronger emphasis at the very beginning)

However, you would not usually split it awkwardly, for example:

• ✗ écoute en silence le violon is understandable but less natural here; French tends to keep verb + direct object together: écoute le violon en silence.

Because the grammatical subject in this sentence is chaque spectatrice, which is singular.

So the verb must be in 3rd person singular:

• elle applaudit → chaque spectatrice applaudit

If you changed the subject to a plural, the verb would change too:

• Toutes les spectatrices applaudissent à la fin du concert.
• Les spectateurs applaudissent à la fin du concert.

• applaudir = to applaud (someone / something) or to clap

  • Le public applaudit.
  • Ils applaudissent le pianiste.

• s’applaudir = to applaud oneself (reflexive)

  • Ils s’applaudissent. = They clap for themselves.

In your sentence, you want the simple verb applaudir with an implicit object (we know they are applauding the performance), so applaudit is correct.

Several points here:

1. fin is feminine, so you must say la fin, not le fin.

2. The usual expression is à la fin de + noun:

   • à la fin du concert
   • à la fin du film
   • à la fin de la journée

3. du is the contraction of de + le:

   • à la fin de + le concert → à la fin du concert

So:

• à la fin du concert = correct
• ✗ au fin du concert is wrong (wrong gender and wrong preposition pattern).

Yes. You can move the time expression to the beginning for emphasis or stylistic variety:

• À la fin du concert, chaque spectatrice écoute le violon en silence et applaudit.

This slightly changes the rhythm, but it is grammatically correct. Both orders are fine:

• Chaque spectatrice… et applaudit à la fin du concert.
• À la fin du concert, chaque spectatrice… et applaudit.