Заміна товару займає тиждень.

Because товару is in the genitive singular and depends on заміна.

The phrase заміна товару literally means replacement of the product / exchange of the product. In Ukrainian, a noun like заміна often takes another noun in the genitive to show what is being replaced.

• заміна = replacement
• товар = product, item, goods
• товару = of the product

So:

• заміна товару = replacement of the product

This is very similar to other noun + genitive combinations in Ukrainian.

It is singular.

• товар = a product / an item
• товару = of the product / of the item

A plural form would look different, for example:

• товари = products / goods
• товарів = of the products / of the goods

So заміна товару usually means replacement of a product/the product, not replacement of products.

Заміна is a noun meaning replacement, exchange, or substitution.

In this sentence, it most naturally means something like:

• product replacement
• exchange of an item
• replacing the product

It comes from the same word family as verbs like:

• замінити = to replace
• міняти / змінювати = to change

So the sentence uses a noun phrase rather than a verb phrase. Instead of saying To replace the product takes a week, Ukrainian says The replacement of the product takes a week.

Займає means takes, in the sense of takes time or occupies time.

So:

• займає тиждень = takes a week

This is a very common Ukrainian way to talk about duration.

Examples:

• Це займає годину. = It takes an hour.
• Ремонт займає два дні. = The repair takes two days.

Literally, the verb займати can also mean to occupy, but in time expressions it is best understood as to take.

Because the subject is заміна, which is a singular feminine noun.

In the present tense, Ukrainian verbs agree with the subject in person and number. Here the subject is:

• заміна = replacement

That is third person singular, so the verb is:

• займає = takes

If the subject were plural, the verb would also be plural:

• Заміни товару займають тиждень. = Product replacements take a week.

Here тиждень is in the accusative singular, because it is the direct object of займає.

In Ukrainian, expressions of duration often use the accusative:

• займає годину = takes an hour
• займає день = takes a day
• займає тиждень = takes a week

For the noun тиждень, the accusative singular is the same as the nominative singular because it is inanimate:

• nominative: тиждень
• accusative: тиждень

You might also see тижня in other structures, for example:

• протягом тижня = during the week / over the course of a week

But after займає, тиждень is the normal form.

It can match both in English, depending on context.

The Ukrainian sentence uses a noun:

• заміна товару = replacement of the product

But in natural English, this is often translated more smoothly as:

• Replacing the product takes a week.

So grammatically, Ukrainian is using a noun phrase, while English often prefers a gerund phrase. Both express the same idea.

Yes. Товар can mean:

• product
• item
• merchandise
• sometimes goods

In this sentence, though, товару most naturally sounds like of the item/product, especially in a customer-service context.

If someone is talking about replacing a purchased item, товар is a very normal word.

The most neutral order is:

• Заміна товару займає тиждень.

This puts the subject first, then the verb, then the time expression.

Ukrainian word order is fairly flexible, so other orders are possible, but they would sound more marked or emphatic. For example:

• Тиждень займає заміна товару.
  This emphasizes a week.

For a learner, the original order is the best standard pattern to remember.

Because Ukrainian has no articles.

So товар or товару can mean:

• a product
• the product
• sometimes just product in a general sense

The exact meaning depends on context.

That is why заміна товару can be understood as:

• replacement of the product
• replacement of a product
• product replacement

English has to choose an article, but Ukrainian does not.

The usual stress is:

• замі́на
• това́ру
• займа́є
• ти́ждень

So the whole sentence is pronounced roughly as:

• замі́на това́ру займа́є ти́ждень

Stress is important in Ukrainian, because it is not always predictable.

Yes, but the meaning shifts slightly.

• Заміна товару займає тиждень. = The replacement takes a week.
• Заміна товару триває тиждень. = The replacement lasts a week.

Both can work, but займає is especially natural when talking about how much time something requires.

So for it takes a week, займає is a very good match.

Заміна is in the nominative singular, because it is the subject of the sentence.

Breakdown:

• Заміна = subject, nominative singular
• товару = genitive singular, dependent on заміна
• займає = third person singular present
• тиждень = accusative singular, duration/direct object

So the structure is:

[Subject] + [Verb] + [Time expression/object]

Yes. The present tense in Ukrainian is often used for general facts, procedures, or usual timing.

So Заміна товару займає тиждень can mean:

• as a general policy, product replacement takes a week
• normally, the replacement process takes a week

It does not have to mean that the replacement is happening at this exact moment.