Cada vez que entramos en el laboratorio, la profesora de química nos pide calma.

Cada vez que means every time that or whenever.

In this sentence, it introduces a repeated situation:

• Cada vez que entramos en el laboratorio... = Every time we go into the laboratory...

It is a very common structure for habits or repeated actions.

Examples:

• Cada vez que llueve, me quedo en casa. = Every time it rains, I stay at home.
• Cada vez que la veo, sonríe. = Every time I see her, she smiles.

Here, the present tense is used for a habitual/repeated action.

So entramos does not mean just we are entering right now. It means something like:

• we go in
• we enter
• we go into

Because the sentence is about something that happens regularly, Spanish uses the present:

• Cada vez que entramos en el laboratorio... = Every time we enter the lab...

This is very normal in Spanish.

Also, note that entramos can also be a preterite form (we entered), but here the context clearly makes it present.

In standard Spanish, entrar is commonly followed by en before a place:

• entrar en la casa
• entrar en el aula
• entrar en el laboratorio

So:

• entramos en el laboratorio = we go into the laboratory

You may sometimes hear entrar + place directly in some contexts or regions, but for learners, entrar en is the safest and most standard choice.

Spanish uses the definite article much more often than English.

Here, el laboratorio refers to the specific lab that both speaker and listener already know about, so the article sounds natural:

• en el laboratorio = in/into the laboratory

English sometimes drops articles where Spanish keeps them, but in Spanish this is normal.

Literally, la profesora de química means the teacher/professor of chemistry.

In natural English, we usually say:

• the chemistry teacher

Spanish often uses de to show the subject or area associated with a person:

• profesor de español = Spanish teacher
• profesora de matemáticas = maths teacher
• profesor de historia = history teacher

So de química tells you what subject she teaches.

Because the teacher is female.

• profesor = male teacher
• profesora = female teacher

Spanish nouns for professions often change form depending on gender. Since the sentence says la profesora, we know the teacher is a woman.

Nos means to us.

The verb pedir often works like this:

• pedir algo a alguien = to ask someone for something

In this sentence:

• la profesora = the teacher
• nos = to us
• pide = asks
• calma = calm / calmness

So:

• la profesora nos pide calma = the teacher asks us to stay calm / asks us for calm

Even though English often says asks us to be calm, Spanish can express it with the noun calma.

Both are possible, but they are slightly different in style.

• nos pide calma = she asks us for calm / asks us to stay calm
• nos pide que estemos tranquilos = she asks us to be calm

Pedir calma is shorter and very natural. Spanish often uses a noun where English might prefer an infinitive or clause.

Compare:

• pedir silencio = ask for silence
• pedir ayuda = ask for help
• pedir paciencia = ask for patience

So pedir calma is an idiomatic, compact way to say it.

Because abstract nouns often appear without an article after verbs like pedir.

So Spanish naturally says:

• pedir calma
• pedir paciencia
• pedir silencio

rather than:

• pedir la calma

Using la calma here would sound unusual in this context.

In other words, calma is being treated as an uncountable abstract idea, much like silence or patience in English.

Here it takes the indicative:

• Cada vez que entramos...

That is because the sentence refers to something habitual and real: something that regularly happens.

With cada vez que, Spanish normally uses the indicative when talking about repeated facts:

• Cada vez que viene, trae pan. = Every time he comes, he brings bread.

The subjunctive is not normally used in this kind of habitual statement.

Yes, absolutely. That is a very natural translation.

Possible English versions include:

• Every time we enter the laboratory, the chemistry teacher asks us to stay calm.
• Whenever we go into the lab, the chemistry teacher asks us to keep calm.
• Whenever we enter the lab, the chemistry teacher asks us for calm.
  
  • This last one is more literal, but less natural in English.

So the Spanish is flexible in translation, but the core idea is the same.

It is neutral standard Spanish.

Nothing in it is especially slangy or especially formal. It would sound normal in everyday speech, in school contexts, and in writing.

A few points:

• laboratorio is standard
• la profesora de química is standard
• nos pide calma is natural and idiomatic

So this is a good model sentence for learners.