Im Supermarkt kaufe ich eine Dose Tomaten und eine Packung Nudeln.

German often puts a time/place expression first for emphasis or style.

So instead of:

• Ich kaufe im Supermarkt ...

you can also say:

• Im Supermarkt kaufe ich ...

Both are correct. Starting with Im Supermarkt puts the focus on where the action happens.

A key rule in German is that the conjugated verb must still stay in second position.
That is why you get:

• Im Supermarkt
  • kaufe
    • ich

not:

• Im Supermarkt ich kaufe

Im is a contraction of:

• in dem → im

So:

• im Supermarkt = in the supermarket

This contraction is very common and usually preferred in normal German.

Examples:

• im Haus = in dem Haus
• im Garten = in dem Garten

Because German uses the verb-second (V2) rule in main clauses.

In this sentence, Im Supermarkt takes the first position. Once that happens, the conjugated verb must come next:

• Im Supermarkt / kaufe / ich / ...

If the sentence started with ich, then you would say:

• Ich kaufe im Supermarkt eine Dose Tomaten und eine Packung Nudeln.

So the subject ich is not always first in German. The verb’s position is more important.

Both Dose and Packung are feminine nouns, so in the accusative singular they take eine.

• die Dose → eine Dose
• die Packung → eine Packung

They are in the accusative here because they are the direct objects of kaufe.

Compare:

• Ich kaufe eine Dose.
• Ich kaufe eine Packung.

Because the sentence means:

• a can of tomatoes
• a packet of noodles/pasta

In German, after container or quantity words like Dose, Packung, Glas, Flasche, the thing inside is often just named directly:

• eine Dose Tomaten
• eine Packung Nudeln
• ein Glas Wasser
• eine Flasche Milch

Here, Tomaten and Nudeln are plural because we are talking about tomatoes and noodles/pasta in general, not one single tomato or one single noodle.

After words like Dose and Packung, German often uses the following noun without an article.

So these are natural:

• eine Dose Tomaten
• eine Packung Nudeln
• eine Tasse Kaffee

This works a bit like English:

• a can of tomatoes
• a pack of noodles

German often leaves out an extra article in this kind of structure.

Not exactly.

The most natural everyday phrasing is:

• eine Dose Tomaten

You could say:

• eine Dose mit Tomaten

but that sounds more literal, like a can containing tomatoes.

Eine Dose von Tomaten is generally not the normal way to say this in German.

So for shopping language, eine Dose Tomaten is the standard, idiomatic form.

In many contexts, Nudeln can mean either noodles or pasta, depending on the situation.

In a supermarket sentence like this, eine Packung Nudeln usually means:

• a packet of pasta

even though the literal English-looking translation might be noodles.

So the exact English word depends on context.

Because all nouns are capitalized in German.

So in this sentence, these words are capitalized because they are nouns:

• Supermarkt
• Dose
• Tomaten
• Packung
• Nudeln

This is a basic and very important spelling rule in German.

It is in the dative case.

That is because in can take either:

• accusative for movement toward a place
• dative for location in a place

Here, the meaning is location: the buying happens in the supermarket, not into the supermarket.

So:

• in dem Supermarkt → dative
• contracted: im Supermarkt

Compare:

• Ich bin im Supermarkt. = location
• Ich gehe in den Supermarkt. = movement into

Yes, absolutely.

That version is also correct:

• Ich kaufe eine Dose Tomaten und eine Packung Nudeln im Supermarkt.

The difference is mainly focus and style.

• Im Supermarkt kaufe ich ... emphasizes the place a bit more.
• Ich kaufe ... im Supermarkt. sounds more neutral and starts with the subject.

German allows this flexibility as long as the verb-second rule is respected in the main clause.

Und simply connects two noun phrases:

• eine Dose Tomaten
• eine Packung Nudeln

It does not change the word order of the clause.

So the main structure stays:

• Im Supermarkt / kaufe / ich / [object 1] und [object 2]

If und were connecting two full clauses, then each clause would have its own normal word order. But here it is only joining two objects.

Yes, it is natural and correct.

A native speaker might also say:

• Im Supermarkt kaufe ich Tomaten aus der Dose und eine Packung Nudeln.
• Ich kaufe im Supermarkt eine Dose Tomaten und eine Packung Nudeln.

But your original sentence is perfectly normal. It sounds like a simple textbook-style statement about buying groceries, which is exactly the kind of sentence learners often practice.