Learn Hardcore Russian: Невозможно работать, когда интернет пропадает каждую минуту. - It is impossible to work when the internet drops every minute.

Russian often uses impersonal constructions with predicatives like невозможно. Невозможно работать literally means “It is impossible to work,” but there is no dummy “it” in Russian. You could say Это невозможно, but if you name the action, you use the infinitive: Невозможно работать.

Why is работать in the infinitive and not работаю or работать невозможно?

The infinitive (работать) names the general action in impersonal “modal” statements: невозможно/нужно/можно + infinitive.
Работать невозможно is also correct; it just flips the order for emphasis.
Я не могу работать is a personal version (“I can’t work”), but the original sentence expresses a general, objective impossibility.

What is the subject of the sentence? Is there any?

In the main clause, there is no grammatical subject; it’s an impersonal construction with невозможно. In the subordinate clause (когда интернет пропадает каждую минуту), интернет is the subject (nominative).

Why is there a comma before когда?

Когда introduces a subordinate clause of time. Russian punctuation requires a comma to separate the main clause (Невозможно работать) from the subordinate one (когда…).

Does когда here mean “whenever” or “when”?

Both, depending on context. In habitual statements like this, когда often has the sense of “whenever”: “It’s impossible to work whenever the internet keeps dropping out.” Using если (“if”) would make it slightly more conditional: …если интернет пропадает…

Why is it пропадает (imperfective present) and not пропадёт or пропал?

Пропадает (imperfective present) is used for repeated/habitual actions and ongoing tendencies—“keeps going out.”
Пропадёт (perfective future) would mean “will (once) go out.”
Пропал (perfective past) refers to a single completed disappearance in the past.

Could I say интернет не работает instead of интернет пропадает?

Yes, but the nuance differs:

Интернет пропадает suggests intermittent drops: it disappears and comes back.
Интернет не работает suggests it doesn’t work (possibly continuously or at a given moment) without emphasizing the on–off nature. For intermittent connection, пропадает, обрывается, or colloquial отваливается are common.

Why is интернет lowercase? What are its gender and case?

It’s lowercase in Russian as a common noun: интернет.
Gender: masculine, inanimate.
Case here: nominative (it’s the subject of the subordinate clause: интернет пропадает).

What case is каждую минуту, and why?

Accusative. Time expressions that mean “for how long” or “how often” often use the accusative:

каждую минуту (every minute, fem. acc. singular)
Compare: каждый час (masc. acc. inanimate = nominative form), каждые пять минут (acc. plural with a numeral; the noun after 5+ goes to genitive plural: минут).

How do I say other frequencies correctly?

Every second: каждую секунду
Every hour: каждый час
Every day: каждый день
Every five minutes: каждые пять минут
Constantly: постоянно
All the time: всё время

Is невозможно written as one word or two?

One word: невозможно. The split form не возможно is incorrect here.

Where does the stress fall in these words?

невозмо́жно
работа́ть
интерне́т
пропада́ет
ка́ждую мину́ту

Can I change the word order to когда пропадает интернет?

Yes. Both когда интернет пропадает and когда пропадает интернет are correct. Russian word order is flexible; moving интернет after the verb can slightly shift emphasis to the verb or the fact of disappearing.

Could I use нельзя instead of невозможно?

You can: Нельзя работать, когда… But note the nuance:

Невозможно = not possible (objective impossibility).
Нельзя = not allowed / cannot (may be about prohibition or impossibility depending on context). Here it would be understood as “cannot,” but невозможно is clearer for physical/practical impossibility.

Are there synonyms for пропадает that fit this context?

Yes:

обрывается (the connection gets cut off; often with связь/соединение)
исчезает (disappears; more general)
Colloquial: отваливается, падает (about the connection) Examples:
Интернет всё время обрывается.
Соединение периодически пропадает.

Is it natural to move каждую минуту earlier in the clause?

It’s possible but less typical in neutral style. Standard is end placement: …интернет пропадает каждую минуту. Fronting adds emphasis:

…когда каждую минуту пропадает интернет (emphasizes the frequency)
Каждую минуту интернет пропадает. (standalone sentence; marked for emphasis)