Мы давно дружим и можем болтать на кухне хоть целый час.

Yes. Russian often drops subject pronouns when the verb already makes the subject clear.

• дружим already means we are friends / we’ve been friends
• можем already means we can

So Давно дружим и можем болтать... is possible in conversation.

Here, мы is included for one of these common reasons:

• to make the sentence clearer
• to sound a bit more complete
• to give slight emphasis to we

So мы is not strictly necessary, but it is perfectly natural.

Давно means for a long time / long ago, depending on context. In this sentence, it means:

• we have been friends for a long time

It is placed before дружим because it modifies the verb and sets the time frame of the relationship.

Russian word order is flexible, but мы давно дружим is the most neutral and natural order here.

Compare:

• Мы давно дружим = neutral, standard
• Мы дружим давно = also possible, but the timing gets slightly more focus

Дружить means to be friends or to have a friendship. It does not work exactly like English to friend.

So:

• Мы дружим = We are friends
• more literally: We have a friendship / We are on friendly terms

It is a normal Russian verb for describing an ongoing friendship.

If you want to mention the other person explicitly, Russian often uses с + instrumental:

• Я дружу с Анной = I’m friends with Anna

In your sentence, no object is needed, because мы already tells you the two people are friends with each other.

This is a very common Russian-English difference.

Russian often uses the present tense for a state that began in the past and still continues now.

So:

• Мы давно дружим literally looks like We are friends for a long time
• natural English becomes We have been friends for a long time

Russian does not need a special present perfect form the way English does. The present tense plus a word like давно often does the job.

Болтать is more informal and has a specific tone. It means something like:

• to chat
• to talk casually
• to chatter

It suggests relaxed, easy, often unimportant conversation.

By contrast:

• говорить = to speak / to talk in a broader, more neutral sense

So:

• можем болтать на кухне sounds warm, casual, and conversational
• it is not formal speech, serious discussion, or a speech-like situation

This fits the idea of close friends comfortably talking together.

After мочь (can / be able to), Russian normally uses an infinitive:

• можем болтать = we can chat
• могу читать = I can read
• они могут прийти = they can come

So можем is the conjugated verb, and болтать stays in the infinitive.

Also, болтать is imperfective, which fits well here because the sentence describes an activity in a general, ongoing, non-completed way.

This is a great question, because English speakers often expect in the kitchen to match в кухне.

In Russian, на кухне is the normal idiomatic way to say in the kitchen / in the kitchen area / in the kitchen as a lived space.

So:

• на кухне = the usual choice
• в кухне is much less natural in most everyday contexts

Russian uses на with some places where English uses in. This is something you often just have to learn as a fixed usage.

Also note the case:

• на кухне
• preposition на
  • prepositional case for location
• кухня → кухне

Кухне is the prepositional case singular of кухня.

The basic form is:

• кухня = kitchen

After на when talking about location, Russian usually uses the prepositional case:

• на кухне = in/on the kitchen space

So the ending changes like this:

• кухня → кухне

This is a regular pattern for many feminine nouns ending in -я.

Here хоть is a particle meaning something like:

• even
• as much as
• a full
• for as long as

In this sentence, хоть целый час means:

• for even a whole hour
• for a full hour
• for as long as an hour

It adds emphasis, suggesting that chatting that long is easy or unsurprising for these people.

This is not the same as the common learner meaning of хоть as at least in every context. Russian хоть is flexible and often depends on the phrase around it.

Целый literally means whole / entire.

So:

• час = an hour
• целый час = a whole hour

It adds emphasis. It suggests that the amount of time feels substantial, complete, or noteworthy.

In this sentence, хоть целый час gives the idea:

• we can sit and chat for a whole hour
• we can easily chat for a full hour

So целый is not required for the basic meaning, but it makes the expression more vivid.

Yes. Час here is in the accusative case.

Russian often uses the accusative to express duration of time:

• ждать час = to wait for an hour
• работать весь день = to work all day
• спать всю ночь = to sleep all night

So in хоть целый час, the phrase is functioning as a duration expression: for a whole hour.

For this noun, the accusative singular looks the same as the nominative singular:

• nominative: час
• accusative: час

That is why there is no visible change in the noun itself.

Imperfective verbs are the natural choice here because the sentence describes:

• an ongoing relationship
• a repeated or general ability
• an activity viewed as a process, not a completed result

More specifically:

• дружим describes a continuing state: we are friends
• болтать describes casual chatting as an activity, with no focus on finishing it

If the sentence used perfective forms, it would sound wrong or would shift the meaning toward completion or a one-time result, which is not the point here.

Yes, Russian word order is flexible, but the version you have is the most neutral and natural:

• Мы давно дружим и можем болтать на кухне хоть целый час.

Other orders are possible, but they change emphasis. For example:

• Мы можем хоть целый час болтать на кухне.
  Stronger focus on for a whole hour

• На кухне мы можем болтать хоть целый час.
  Stronger focus on in the kitchen

• Мы давно дружим, и на кухне можем болтать хоть целый час.
  Slight pause and stronger separation between the two ideas

So the original order is a good standard one for learners to model.

Yes. The sentence has a natural cause-and-result feel, even though it does not state that explicitly.

• Мы давно дружим = we have known each other / been friends for a long time
• и можем болтать на кухне хоть целый час = and because of that, we can comfortably chat for ages

So the second part feels like a natural consequence of the first:

• long friendship → ease, comfort, relaxed conversation

Russian does not need to add поэтому (therefore) here. The connection is understood from context.