Il gas è chiuso.

In Italian, the definite article is used very often, including in cases where English might sound more flexible.

Here, il gas means the gas or more specifically the gas supply / gas line / gas tap depending on context.

So Italian naturally says:

• Il gas è chiuso.
• L’acqua è aperta.
• La porta è chiusa.

Even if English might sometimes say something shorter like Gas is off, Italian normally keeps the article: il gas.

Yes. Gas is treated as a masculine noun, so it takes masculine forms:

• il gas
• un gas

That is why the adjective is also masculine singular:

• chiuso

not chiusa.

Because chiuso agrees with gas, and gas is masculine singular.

Agreement pattern:

• masculine singular → chiuso
• feminine singular → chiusa
• masculine plural → chiusi
• feminine plural → chiuse

So:

• Il gas è chiuso.
• La porta è chiusa.

Literally, chiuso means closed.

In this sentence, though, it usually means something like:

• shut off
• turned off
• closed off

So Il gas è chiuso is not saying the gas itself is physically “closed” in some abstract sense. It means the gas supply has been shut off, usually by closing a valve or tap.

È is the third-person singular of essere (to be), so it means is.

The structure is:

• Il gas = the gas
• è = is
• chiuso = closed / shut off

So the sentence is literally:

• The gas is closed

which idiomatically means:

• The gas is shut off

This is a very common Italian pattern: noun + essere + adjective/past participle.

Because è with an accent means is.

Without the accent, e means and.

So these are different words:

• è = is
• e = and

This is an important spelling distinction in Italian.

Yes, it is natural, especially when talking about the gas supply in a home, kitchen, or building.

It suggests that the gas has been shut off at the source, such as a valve or control.

For example:

• Controlla se il gas è chiuso.
  Check whether the gas is shut off.

• Quando esci, lascia il gas chiuso.
  When you leave, leave the gas turned off.

Sometimes, but the meaning is not exactly the same.

• Il gas è chiuso usually refers to the gas supply being shut off
• Il gas è spento sounds more like a flame or appliance using gas is off/extinguished

So:

• chiudere il gas = to shut off the gas supply
• spegnere il gas may be used in everyday speech, but it often suggests turning off a burner, stove, or flame

If you want to be precise about the supply, chiuso is better.

Yes. Chiuso is the past participle of chiudere (to close).

In this sentence, it functions like an adjective describing the state of the gas supply:

• Il gas è chiuso = the gas is in a closed/shut-off state

Italian very often uses past participles this way:

• La finestra è aperta = the window is open
• La porta è chiusa = the door is closed
• Il negozio è chiuso = the shop is closed

Yes, absolutely. These are very common expressions.

• aprire il gas = to turn on / open the gas
• chiudere il gas = to turn off / shut off the gas

Examples:

• Apri il gas.
  Turn on the gas.

• Chiudi il gas.
  Turn off the gas.

These are standard verbs used for valves, taps, and supply lines.

Gas is generally invariable in form, so the plural is also gas.

• singular: il gas
• plural: i gas

Examples:

• Questo gas è pericoloso.
• Questi gas sono pericolosi.

But in everyday life, you will much more often see the singular.

It is pronounced very similarly to English gas, but with a clear Italian sound and no strong English-style diphthongs.

A rough guide is:

• gas → sounds like gahs

Also note:

• è is pronounced like eh
• chiuso sounds roughly like KYOO-zo

So the full sentence is approximately:

• eel gahs eh KYOO-zo

That is only an approximation, but it can help at the beginning.