La acuarela está en la exposición.

Because acuarela is a feminine noun in Spanish, so it takes the feminine article la.

• la acuarela = the watercolor / the watercolor painting
• una acuarela = a watercolor / a watercolor painting

This is something you usually have to learn with the noun. The ending -a often signals a feminine noun, and here that pattern fits.

Acuarela can mean:

• watercolor as an art medium
• a watercolor painting

In this sentence, La acuarela está en la exposición, it most naturally means the watercolor painting is in the exhibition.

So even if English might say the watercolor, Spanish often uses acuarela the same way.

Spanish uses estar for location in almost all cases.

So:

• La acuarela está en la exposición = the painting is located in the exhibition

You would not normally say La acuarela es en la exposición.

A helpful rule:

• ser = identity, description, origin, time, etc.
• estar = location, condition, temporary states

Since this sentence tells you where the watercolor is, está is the correct choice.

Está is the third-person singular form of estar in the present tense.

It can mean:

• he/she is
• it is
• you are (formal singular, usted)

In this sentence, it means it is, referring to la acuarela.

Full present tense of estar:

• yo estoy
• tú estás
• él/ella/usted está
• nosotros/nosotras estamos
• ustedes están
• ellos/ellas están

The accent mark in está shows which syllable is stressed: es-TÁ.

It also helps distinguish forms in writing. In pronunciation, the stress matters:

• está → stress on the last syllable

Without the accent, esta is a different word:

• esta = this (feminine), as in esta acuarela = this watercolor

So the accent is important both for pronunciation and meaning.

En usually means in, on, or at, depending on context.

Here it means in / at:

• en la exposición = in the exhibition / at the exhibition

Spanish uses en very often for location:

• en el museo = in the museum
• en la mesa = on the table
• en casa = at home

So en is the normal preposition for saying where something is.

Because exposición is also a feminine noun, so it takes la in the singular:

• la exposición = the exhibition
• una exposición = an exhibition

Spanish uses definite articles more often than English, so keeping la is very natural here.

Not always. Exposición can mean different things depending on context, such as:

• exhibition or display
• presentation
• exposure

In this sentence, because we are talking about a watercolor painting, the most natural meaning is art exhibition.

So here:

• la exposición = the exhibition

Yes, Spanish word order is flexible, though the original sentence is the most neutral and natural:

• La acuarela está en la exposición.

You could also say:

• En la exposición está la acuarela.

That version puts more emphasis on where it is. It can sound a little more literary or contrastive depending on context.

For a beginner, the standard pattern is best:

• subject + verb + place

A simple pronunciation guide is:

lah ah-kwah-REH-lah ehs-TAH en lah ehk-spoh-see-SYOHN

A few notes:

• acuarela has the stress on re: ah-kwah-REH-lah
• está has the stress on tá
• exposición has the stress on the last syllable: ehk-spoh-see-SYOHN

In much of Latin America, c before i is pronounced like s, so exposición sounds like ehk-spoh-see-SYOHN.

Normally, no. In standard Spanish, countable singular nouns usually need an article or another determiner.

So you would say:

• La acuarela está en la exposición.
• Una acuarela está en la exposición.
• Esta acuarela está en la exposición.

But not normally:

• Acuarela está en la exposición.

Leaving out the article there sounds incomplete or unnatural.

You would make both the noun and the verb plural:

• Las acuarelas están en la exposición.

Changes:

• la → las
• acuarela → acuarelas
• está → están

So:

• La acuarela está... = one watercolor is...
• Las acuarelas están... = the watercolors are...