Die Karte enthält einen Chip.

Because Karte is a feminine noun in German. In the nominative singular, the definite article for feminine nouns is die.

So:

• die Karte = the card

This has to do with grammatical gender, not biological gender. In German, every noun has a gender, and Karte happens to be feminine.

Because Chip is the direct object of the sentence, so it is in the accusative case.

The verb enthalten takes an object: the card contains what? → a chip.

Since Chip is masculine (der Chip), its indefinite article changes in the accusative:

• nominative: ein Chip
• accusative: einen Chip

That is why the sentence says einen Chip.

You can tell from both meaning and case marking:

• die Karte is in the nominative, which is typically the subject case.
• einen Chip is in the accusative, which is typically the direct object case.

So:

• die Karte = the thing doing the containing
• einen Chip = the thing being contained

Because enthält is the conjugated form used with er/sie/es in the present tense.

The dictionary form is enthalten = to contain.

Here, the subject is die Karte, which is grammatically third-person singular (she/it), so the verb must match it:

• ich enthalte
• du enthältst
• er/sie/es enthält

So Die Karte enthält ... means The card contains ...

This verb has a stem-vowel change in the present tense for some forms.

The base verb is enthalten, but in the du and er/sie/es forms, the a changes to ä:

• ich enthalte
• du enthältst
• er/sie/es enthält

This is similar to other strong verbs in German that change their vowel in the present tense.

The sentence follows the normal German main clause word order:

Subject + verb + object

• Die Karte = subject
• enthält = verb
• einen Chip = object

So the pattern is:

• Die Karte enthält einen Chip.

This is very standard German word order.

Yes, you can, but it changes the emphasis.

German allows different word orders more easily than English, as long as the finite verb stays in second position in a main clause.

So both are possible:

• Die Karte enthält einen Chip. = neutral statement
• Einen Chip enthält die Karte. = emphasizes a chip

The first version is the most natural if you are just stating the fact.

Because in German, all nouns are capitalized.

So:

• die Karte
• ein Chip

This is one of the most noticeable spelling rules in German.

Yes. Die Karte hat einen Chip is also correct and natural.

The difference is small:

• hat einen Chip = has a chip
• enthält einen Chip = contains a chip

Enthält sounds a little more formal or technical, while hat is more everyday language.

A natural way is:

• Die Karte enthält keinen Chip.

Here, keinen is the negative form that matches a masculine accusative noun:

• einen Chip → keinen Chip

So:

• Die Karte enthält einen Chip. = The card contains a chip.
• Die Karte enthält keinen Chip. = The card does not contain a chip.

If you mean the cards contain a chip, you would say:

• Die Karten enthalten einen Chip.

If you mean the card contains chips, you would say:

• Die Karte enthält Chips.

And if both are plural:

• Die Karten enthalten Chips.

Notice the changes:

• Karte → Karten
• enthält → enthalten with a plural subject

A simple approximation is:

• enthält ≈ ent-helt with an eh-type vowel in the stressed syllable

A few useful points:

• the ä is pronounced somewhat like the vowel in English bed, though not exactly the same
• the h is not strongly pronounced on its own here; it helps show vowel length/history in the spelling
• the stress is on the second part: ent-HÄLT

And Chip is usually pronounced much like English chip.