האריזה של הלחם הטרי פתוחה, ולכן אני לא רוצה לקנות אותו.

Because ה־ is the Hebrew definite article, meaning the.

• אריזה = package / packaging
• האריזה = the package / the packaging
• לחם = bread
• הלחם = the bread

Hebrew adds ה־ directly to the beginning of the noun, instead of using a separate word like English the.

Because the noun is definite, the adjective must also be definite.

In Hebrew, when a noun has ה־ and an adjective describes it, the adjective usually gets ה־ too:

• לחם טרי = fresh bread
• הלחם הטרי = the fresh bread

This is a very common Hebrew pattern:

• הספר החדש = the new book
• הילדה הקטנה = the little girl

So הלחם הטרי literally follows the pattern the-bread the-fresh.

Because in Hebrew, adjectives normally come after the noun they describe.

So:

• לחם טרי = literally bread fresh
• בית גדול = literally house big
• ילד חכם = literally boy smart

This is different from English, where adjectives usually come before the noun.

Because פתוחה agrees with האריזה, and אריזה is a feminine singular noun.

Hebrew adjectives and participles must agree with the noun in:

• gender
• number
• definiteness

So:

• פתוח = masculine singular
• פתוחה = feminine singular
• פתוחים = masculine plural
• פתוחות = feminine plural

Since האריזה is feminine singular, Hebrew uses פתוחה.

של means of and is a very common way to show possession or connection.

So:

• האריזה של הלחם הטרי = the package of the fresh bread
• more naturally in English: the packaging of the fresh bread or the bread’s packaging

Hebrew often uses של where English might use:

• of
• apostrophe-s
• a noun-noun combination

For learners, של is one of the easiest and safest ways to express possession.

Sometimes yes, using the construct state (called smikhut), but not every phrase sounds equally natural that way.

For example, Hebrew often prefers:

• אריזת הלחם = the bread packaging / the package of the bread

But the sentence you were given uses של, which is very common and very clear for learners.

A useful rule:

• של is often easier and more transparent.
• Construct forms are also common, but they require more familiarity with Hebrew patterns.

לכן means therefore / so / for that reason.

The sentence already has a comma connecting two ideas:

• The packaging of the fresh bread is open
• therefore I do not want to buy it

So לכן works well by itself.

You could also hear:

• אז = so
• ולכן = and therefore

But ..., ולכן ... and ..., לכן ... can both appear depending on style. In your sentence, לכן is simply the connector meaning therefore.

Yes. רוצה here is present tense.

Hebrew often uses a present-tense verb plus an infinitive, just like English:

• אני רוצה לקנות = I want to buy
• אני לא רוצה לקנות = I do not want to buy

Breakdown:

• אני = I
• לא = not
• רוצה = want (literally wanting, masculine singular form)
• לקנות = to buy

If the speaker were female, she would normally say:

• אני לא רוצה לקנות in everyday unvocalized writing looks the same, but when vocalized/pronounced carefully there is a difference:
  • masculine: rotze
  • feminine: rotza

So in normal Hebrew spelling, masculine and feminine often look identical in this form.

Because אותו already functions as the direct object pronoun him / it.

Compare:

• אני קונה את הלחם = I buy the bread
• אני קונה אותו = I buy it

When the object is a full definite noun, Hebrew often uses את:

• את הלחם

But when the object is replaced by a pronoun like אותו, you do not add a separate את before it.

So:

• לקנות אותו = to buy it not
• לקנות את אותו in this meaning

(There is an את אותו structure in other contexts, but that is a different construction.)

It refers to הלחם (the bread), not האריזה (the package / packaging).

The key clue is grammatical gender:

• לחם is masculine
• אריזה is feminine
• אותו is masculine singular
• the feminine form would be אותה

So if the speaker meant the packaging, Hebrew would say:

• אני לא רוצה לקנות אותה

Because the sentence says אותו, it must refer to the masculine noun הלחם.

Because לקנות is the infinitive to buy, and Hebrew commonly uses an infinitive after verbs like want, can, need, begin, and so on.

Examples:

• אני רוצה לאכול = I want to eat
• הוא יכול לבוא = He can come
• אנחנו צריכים ללמוד = We need to study

So:

• רוצה לקנות = want to buy

The prefix ל־ here is part of the infinitive form.

In this sentence, it functions like an adjective meaning open, but historically/forms-wise it is also the feminine singular form of a participle.

Hebrew often uses participle forms where English uses adjectives or parts of the verb to be.

Since Hebrew usually leaves out the present-tense word is, the sentence says:

• האריזה ... פתוחה literally:
• the packaging ... open

So the meaning is:

• The packaging ... is open

This is a very normal Hebrew sentence pattern.

Because in present tense, Hebrew usually omits the verb to be.

So:

• האריזה פתוחה = The package is open
• הילד עייף = The boy is tired
• אני שמח = I am happy

In past and future, Hebrew does use forms of to be when needed, but in simple present-tense sentences like this, it is normally omitted.