A outra chave está na bolsa.

A is the feminine singular definite article, meaning the.

It agrees with chave, which is a feminine singular noun:

• a chave = the key

In Portuguese, articles are used more often than in English, so a sounds completely natural here.

Outra has to agree with chave in gender and number.

• chave is feminine singular
• so the adjective must also be feminine singular: outra

Compare:

• o outro carro = the other car
• a outra chave = the other key

Yes. In Portuguese, noun gender is not always predictable from the ending.

• chave is feminine: a chave
• even though it ends in -e

This is something learners often just have to memorize noun by noun.

In this sentence, outra usually means the other.

So a outra chave is:

• the other key
• the second key in a known set

Without the article, outra chave could more easily mean another key.

Compare:

• A outra chave = the other key
• Outra chave = another key / a different key

In Portuguese, some adjectives commonly go before the noun, and outro/outra is one of them.

So:

• a outra chave = correct and natural

Saying a chave outra would sound wrong in normal Portuguese.

Portuguese has two main verbs for to be: ser and estar.

Here, está is used because the sentence talks about location:

• está na bolsa = is in the bag/purse

For location, Portuguese normally uses estar, not ser.

Compare:

• A chave está na bolsa. = The key is in the bag.
• A chave é de metal. = The key is made of metal.

Na is a contraction of:

• em = in / on / at
• a = the (feminine singular article)

So:

• em + a = na

That means:

• na bolsa = in the bag/purse

This kind of contraction is very common in Portuguese.

Other examples:

• no = em + o
• nos = em + os
• nas = em + as

Because bolsa here is being used with the definite article a:

• a bolsa = the bag / the purse

So:

• em a bolsa becomes na bolsa

Using just em bolsa would not sound natural in this sentence.

Bolsa often means bag, and in many everyday contexts in Brazil it can specifically mean a purse/handbag.

Depending on context, Portuguese has several words for bag-like objects:

• bolsa = purse, handbag, bag
• sacola = shopping bag, plastic bag
• mala = suitcase
• mochila = backpack

So in this sentence, bolsa often suggests a purse or handbag.

Yes, but it changes the feel of the sentence.

• A outra chave está na bolsa. = The other key is in the bag.
• Outra chave está na bolsa. = Another key is in the bag or A different key is in the bag.

With a, it sounds like both speaker and listener know which other key is being talked about.

It would become:

• As outras chaves estão na bolsa. = The other keys are in the bag.

Notice all the changes:

• a → as
• outra → outras
• chave → chaves
• está → estão

This shows how articles, adjectives, and verbs often change to match number in Portuguese.

Chave is pronounced approximately like SHAH-vee.

A few details:

• ch in Portuguese usually sounds like English sh
• the stress is on the first syllable: CHA-ve

So:

• chave ≈ SHAH-vee

The exact vowel quality depends on accent, but that approximation is helpful for most learners.

The accent in está shows the stressed syllable and helps distinguish pronunciation.

• está = is
• stress falls on the last syllable: es-TÁ

Accent marks in Portuguese are important because they often show:

• stress
• vowel quality
• sometimes the difference between words

So you should write está with the accent.