Há outro frasco no armário, mas a lata de milho ficou aberta.

Here há means there is.

It comes from the verb haver, which is commonly used in Portuguese to express existence:

• Há outro frasco = There is another jar/bottle
• Há dois frascos = There are two jars/bottles

A useful point: há stays the same even when the thing after it is plural. Unlike English, it does not change to match the noun.

Why not the others?

• tem is often used informally in spoken Portuguese to mean there is/there are, but há is the more standard and neutral choice, especially in careful language.
• está means is in the sense of location or state, not existence. So Está outro frasco would not work here.

Also, the h in há is silent.

Because outro can already function as a determiner by itself.

So:

• Há outro frasco = There is another jar/bottle

This is the normal, natural structure.

You may also hear um outro frasco, but that often sounds more emphatic or stylistically marked, like a different/another one. In most ordinary cases, just outro frasco is enough.

No is a contraction of:

• em = in
• o = the (masculine singular)

So:

• em + o = no

That gives:

• no armário = in the cupboard / in the cabinet / in the closet, depending on context

This kind of contraction is very common in Portuguese:

• na = em + a
• nos = em + os
• nas = em + as

Since armário is masculine singular, no is the correct form.

The article a shows that the speaker is referring to a specific can of corn, not just any can of corn.

So:

• a lata de milho = the can of corn
• uma lata de milho = a can of corn

Portuguese often uses definite articles where English sometimes does too, but learners still need to pay attention because article use is very important and very frequent in Portuguese.

In this sentence, a lata de milho sounds like a known, identifiable item.

Portuguese often links nouns with de to show what something contains, is made of, or is associated with.

So:

• lata de milho = literally can of corn
• frasco de vidro = glass jar/bottle
• sumo de laranja = orange juice

This is very normal in Portuguese. English sometimes uses noun + noun combinations, but Portuguese much more often uses de.

That is exactly why it works here.

Ficar + adjective often expresses a resulting state:

• ficou aberta = ended up open / was left open / became open

In this sentence, the idea is not just that the can was open as a description. The idea is that, after some action, it ended up left open.

Compare:

• A lata estava aberta. = The can was open.
  (just describes its state)

• A lata ficou aberta. = The can was left open / ended up open.
  (focuses on the result)

So ficou aberta is very natural here.

Because aberta must agree with lata, which is feminine singular.

In Portuguese, adjectives usually agree with the noun they describe:

• o frasco aberto = the open jar
• a lata aberta = the open can

Even though milho is masculine, the adjective is describing lata, not milho.

That is why the sentence has:

• a lata de milho ficou aberta

not aberto.

Ficou is the pretérito perfeito form of ficar. It is used for a completed event in the past.

Here it suggests that at some point in the past, the can was left open:

• ficou aberta = was left open / ended up open

This tense fits a finished event well.

If you said:

• A lata de milho estava aberta

that would focus more on the state at that moment, not on the action/result that caused it.

Yes, you could say No armário há outro frasco.

Both are correct, but they emphasize slightly different things:

• Há outro frasco no armário
  starts with the existence of the object: There is another jar in the cupboard

• No armário há outro frasco
  starts with the location: In the cupboard, there is another jar

The original version is very natural because existential sentences often begin with há.

The accent marks it as the verb form há from haver and helps distinguish it from other very common words spelled similarly, especially:

• a = to / the (feminine article, depending on context)
• à = contraction of a + a

So:

• há = there is / there are / ago (from haver)
• a = preposition or article
• à = to the / at the

This is a very common point of confusion for learners, so it is worth noticing early.

Here mas simply means but.

It connects two ideas in contrast:

• Há outro frasco no armário
• mas a lata de milho ficou aberta

So the sentence sets up a contrast like:

• there is another container available,
• but the can of corn was left open.

It is a very straightforward use of mas, and it works much like English but.