A lata e a garrafa estão vazias no contêiner.

Because Portuguese normally uses the definite article before each coordinated noun when both are specific items.

So a lata e a garrafa is the natural way to say the can and the bottle.

Both lata and garrafa are feminine singular nouns, so each one takes a:

• a lata
• a garrafa

You may sometimes see article omission in very compact styles, but for normal speech and writing, a lata e a garrafa is the standard form.

Because the subject has two things: a lata e a garrafa.

When two nouns are joined by e (and), Portuguese normally uses a plural verb:

• A lata está vazia.
• A garrafa está vazia.
• A lata e a garrafa estão vazias.

So estão is the 3rd person plural of estar in the present tense.

Portuguese uses estar for:

• location
• temporary states or conditions

In this sentence, the can and the bottle are:

• in a place: no contêiner
• in a condition: vazias

So estão is the right choice.

Using ser here would sound wrong in normal Portuguese, because being empty is treated as a state, not as an essential characteristic.

Because adjectives in Portuguese agree with the nouns they describe.

Here, the adjective vazias describes both lata and garrafa:

• both nouns are feminine
• together they form a plural subject

So the adjective must also be feminine plural:

• singular feminine: vazia
• plural feminine: vazias

Compare:

• A lata está vazia.
• A garrafa está vazia.
• A lata e a garrafa estão vazias.

Because the sentence is talking about the two objects together as one plural subject.

Even though each noun by itself is singular, a lata e a garrafa together require plural agreement:

• plural verb: estão
• plural adjective: vazias

If you separated the ideas into two clauses, then each adjective would be singular:

• A lata está vazia e a garrafa está vazia.

But once combined into one sentence, Portuguese uses the plural.

No is a contraction of:

• em = in
• o = the

So:

• em + o = no

That means no contêiner literally comes from in the container.

This kind of contraction is very common in Portuguese:

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

Because contêiner is a masculine noun in Portuguese:

• o contêiner

Since it is masculine singular, em + o becomes no:

• no contêiner

If the noun were feminine, then you would use na:

• na caixa
• na garrafa

So the choice between no and na depends on the gender of the noun that follows.

Yes. Contêiner is a standard Brazilian Portuguese form for container.

It is a borrowed word, so learners often notice that it looks similar to English. In Brazil, you may also see the English spelling container in some real-world contexts, especially in business or signage, but contêiner is the standard Portuguese spelling learners should know.

The stress falls on têi: con-TÊI-ner.

Because that is a very natural word order in Portuguese.

The sentence first gives the subject:

• A lata e a garrafa

Then the verb and condition:

• estão vazias

Then the location:

• no contêiner

So the flow is: subject + verb + description + location

You can move the location for emphasis:

• No contêiner, a lata e a garrafa estão vazias.

That is still correct, but the original order is the most neutral and natural.

You usually would not do that in normal Portuguese if you mean specific objects.

Without the articles, it sounds less natural in an ordinary sentence and can feel more generic, label-like, or headline-like.

For specific identifiable items, Portuguese strongly prefers:

• A lata e a garrafa estão vazias no contêiner.

So for a learner, it is safest to keep the articles.

Yes. The singular no contêiner normally means both the can and the bottle are in the same container.

If you wanted to say they were in containers more generally or in separate ones, you would need a different wording, such as:

• em contêineres
• or a more explicit sentence explaining that each one is in a different container

So the original sentence most naturally suggests one shared container.