Learn Hardcore Dutch: Als de stroom uitvalt, werkt het licht in de keuken niet meer. - If the power goes out, the light in the kitchen no longer works.

In Dutch, any subordinate (dependent) clause—one introduced by words like als, omdat, terwijl, etc.—puts the conjugated verb at the very end. Here, als starts a conditional subordinate clause, so uitvalt goes to the end:
Als de stroom uitvalt, …

What exactly is uitvallen, and why does uit stay attached here?

Uitvallen is a separable verb: uit- (prefix) + vallen (to fall). It means “to go out” (of power) or “to fail.”

In a main clause you split it: “De stroom valt uit.”
In subordinate clauses (and with perfect tenses), the prefix stays attached: “als de stroom uitvalt” or “de stroom is uitgevallen.”

Why do we use als here? Could we say wanneer or toen instead?

Als = “if” (conditional) or “when/whenever” (general). Here it means “if.”
Wanneer is more formal and mainly “when” for questions or emphasizing time.
Toen is strictly “when” in past contexts.
So for “If the power goes out…” you choose als.

Why is there a comma after “uitvalt”?

Dutch punctuation requires a comma when a subordinate clause precedes the main clause. So you write:
Als de stroom uitvalt, werkt het licht …

Why does the main clause start with werkt instead of het licht?

Once you place a subordinate clause first, Dutch flips the word order of the main clause (inversion). The finite verb comes immediately after the comma, then the subject:
…uitvalt, werkt (verb) het licht (subject) …

What does werkt mean in this context? Could I use doet instead?

Here werken means “to function” or “to operate.” You wouldn’t normally use doen.

Correct: “Het licht werkt niet meer.”
You could ask informally, “Doet het licht het niet meer?” (“Does the light not work anymore?”), but the standard way to say “the light doesn’t work anymore” is with werken.

Why is it het licht and not de licht?

Dutch nouns are either de-words or het-words. Licht is neuter, so it takes het: het licht.

Why is it de stroom and not het stroom?

Stroom is a common gender noun (de-word) in Dutch, so it needs de: de stroom.

What does niet meer add here? Why not just niet?

Niet alone means “not” (right now).
Niet meer means “no longer” or “not anymore,” implying that it worked before but stopped when the power went out.

Can I move in de keuken elsewhere in the sentence?

Yes. Dutch allows some flexibility with adverbial/prepositional phrases. You can say:

“Als de stroom uitvalt, werkt het licht in de keuken niet meer.”
Or “…werkt het licht in de keuken niet meer.”
Both orders are acceptable; you just keep the main clause’s verb-subject-object order (after inversion).