Я открыл банку кукурузы для салата.

Because банку is the direct object of the verb открыл (opened).

The basic dictionary form is банка. But in this sentence, I opened what? → банку, so it has to go into the accusative case.

For a feminine noun ending in -а, the accusative singular usually changes:

• банка → банку
• книга → книгу
• машина → машину

So:

• Я открыл банку = I opened a can / jar

Because кукурузы is in the genitive case, not the accusative.

Here, банка кукурузы means a can of corn. In Russian, after a container word like банка (can/jar), the thing inside is often put in the genitive:

• банка кукурузы = a can of corn
• чашка чая = a cup of tea
• бутылка воды = a bottle of water

So the pattern is:

• банка чего? → кукурузы

It is not the thing being directly opened grammatically. The direct object is банку, and кукурузы just describes what kind of can it is.

Because the preposition для always requires the genitive case.

So:

• салат = dictionary form
• для салата = for salad / for the salad

Other examples:

• для супа = for soup
• для мамы = for mom
• для работы = for work

So in this sentence:

• для салата = for the salad / for salad

Because открыл is perfective, and it shows a completed action: the can was successfully opened.

Russian often has two aspect forms:

• открывать / открывал = imperfective
• открыть / открыл = perfective

Here, the speaker is talking about one finished action, so открыл is the natural choice:

• Я открыл банку кукурузы = I opened the can of corn

If you used открывал, it would sound more like:

• I was opening it
• I used to open it
• I opened it (with focus on process/repetition/context, not just completion)

So for a simple completed event, открыл is exactly what you would expect.

It tells you that the verb is in the past tense and that the subject is masculine singular.

In Russian past tense:

• открыл = masculine
• открыла = feminine
• открыло = neuter
• открыли = plural

So:

• Я открыл банку кукурузы = said by a male speaker
• Я открыла банку кукурузы = said by a female speaker

This is a very common feature of Russian past tense verbs.

Yes, very often.

Russian often drops subject pronouns when the meaning is already clear from the verb form or the context. So:

• Я открыл банку кукурузы для салата.
• Открыл банку кукурузы для салата.

Both can work, depending on context.

Including Я can make the subject more explicit, or add a little emphasis, like I opened it.

So the pronoun is grammatical here, but not always necessary.

No, Russian word order is fairly flexible because the case endings show the grammatical roles.

The neutral, straightforward order here is:

• Я открыл банку кукурузы для салата.

But other orders are possible, depending on emphasis:

• Для салата я открыл банку кукурузы. = As for the salad, I opened a can of corn.
• Банку кукурузы я открыл для салата. = It was a can of corn that I opened for the salad.

The meaning stays basically the same, but the focus changes.

So English relies heavily on word order; Russian relies much more on case endings and uses word order more for emphasis and information structure.

It can mean either one, depending on context.

Russian has no articles like a or the, so салат by itself does not tell you whether it is:

• salad
• a salad
• the salad

So для салата could mean:

• for salad
• for a salad
• for the salad

You have to understand it from the situation.

Because Russian often expresses of-relationships just by putting the second noun in the genitive case, without any extra word.

So:

• банка кукурузы = a can of corn
• стакан молока = a glass of milk
• кусок хлеба = a piece of bread

English uses the separate word of. Russian usually uses a case ending instead.

That is why you see кукурузы rather than a preposition meaning of.

Yes, банка can mean jar or can, depending on context.

In everyday Russian, банка is a common word for a container, especially for food. So банка кукурузы is a natural way to say a can of corn.

Depending on the exact physical container, English might choose:

• can
• tin
• jar

But Russian often still uses банка in this kind of food context.

So the Russian word is a little broader than a single English equivalent.