Bilhandlaren ger köpeavtalet och reservnyckeln när bilen är körklar.

Because -en is the definite ending for many en-words in Swedish.

• en bilhandlare = a car dealer
• bilhandlaren = the car dealer

Swedish usually puts the definite article at the end of the noun instead of using a separate word like English the.

This is one of the biggest differences from English. In Swedish, the is usually attached to the noun as a suffix:

• köpeavtal = purchase agreement

• köpeavtalet = the purchase agreement

• reservnyckel = spare key

• reservnyckeln = the spare key

• bil = car
• bilen = the car

So instead of saying something like the car, Swedish usually says bilen.

Because Swedish nouns belong to different grammatical genders, usually called en-words and ett-words.

• ett köpeavtal → köpeavtalet
• en reservnyckel → reservnyckeln

So the definite singular ending depends on the noun:

• many en-words take -en
• many ett-words take -et

That is why the endings are different.

Yes. Bilhandlaren is built from:

• bil = car
• handlare = dealer / trader

So:

• bilhandlare = car dealer
• bilhandlaren = the car dealer

Swedish uses compounds very freely, often more than English does. Instead of several separate words, Swedish often joins them into one.

It is a compound noun:

• köp / köpe- relates to buying / purchase
• avtal = agreement / contract

So köpeavtal means purchase agreement or sales contract.

The form köpe- is a linking form often used in compounds. You do not always translate each part literally; it is best to learn the whole compound as one vocabulary item.

Because Swedish verbs do not change by person the way English verbs sometimes do.

In English:

• I give
• you give
• he/she gives

In Swedish, the present tense is the same for all persons:

• jag ger
• du ger
• han/hon ger
• de ger

So ger simply means gives / is giving, depending on context.

Yes, körklar is an adjective, and är is the verb to be.

• är = is
• körklar = ready to drive / road-ready

So:

• bilen är körklar = the car is ready to drive

This is a normal Swedish pattern: subject + är + adjective.

Because the adjective agrees with the noun it describes.

Here the noun is:

• bilen = the car

Bil is an en-word, and in predicate position after är, the common-gender singular form is often the basic form:

• bilen är körklar

If it were an ett-word, you would often get -t:

• huset är klart = the house is ready

So körklar matches bil(en).

Körklar is a compound adjective:

• köra = to drive
• klar = ready / clear / finished

Together, körklar means something like:

• ready to drive
• ready for use on the road
• road-ready

In this sentence, it means the car has been prepared and is ready for delivery or use.

Here när means when.

• när bilen är körklar = when the car is ready to drive

It introduces a subordinate clause. The main idea is:

• Bilhandlaren ger köpeavtalet och reservnyckeln
  = The car dealer gives the purchase agreement and the spare key

And then the sentence adds when that happens:

• när bilen är körklar

Because in Swedish subordinate clauses, the word order is often straightforward:

• när
  • subject + verb + adjective
• när bilen är körklar

So it is literally:

• when
  • the car
    • is
      • ready to drive

This is standard subordinate-clause structure in Swedish.

Yes. If the när-clause comes first, the main clause follows normal Swedish verb-second word order:

• När bilen är körklar, ger bilhandlaren köpeavtalet och reservnyckeln.

Notice that ger comes before bilhandlaren in the main clause.

So:

• Bilhandlaren ger ... när bilen är körklar.
• När bilen är körklar, ger bilhandlaren ...

Both are correct, but the word order changes when the sentence starts with the subordinate clause.

Because när already introduces the clause. Swedish does not use att here.

• när = when
• att usually means to or introduces a different kind of subordinate clause, like that

So:

• när bilen är körklar = when the car is ready
• not när att bilen är körklar

That would be ungrammatical.

Yes, depending on context. In practical use, när can sometimes feel like:

• when
• once
• as soon as

In this sentence, it likely means something like:

• the dealer gives the agreement and spare key once / when the car is ready

So the exact English wording may vary a little, even though the Swedish uses när.

Because the sentence refers to specific things: the purchase agreement and the spare key connected with that particular car sale.

In context, these are not just any agreement and any spare key. They are the known, specific ones belonging to the situation. Swedish marks that with the definite forms:

• köpeavtalet
• reservnyckeln

This is very natural in Swedish, just as English would naturally say the purchase agreement and the spare key.