Раз уж ты дома, позвони бабушке, пожалуйста.

Раз уж is a conversational expression meaning something like:

• since
• seeing that
• if you’re already...
• as long as...

In this sentence, it adds a mild “given that this is already the case” feeling:

• Раз уж ты дома... = Since you’re home... / If you’re at home anyway...

Compared with plain раз, раз уж often sounds a little more natural in spoken Russian when the speaker is using an existing situation as a reason for a suggestion or request.

Yes, Russian often omits the subject pronoun when it is clear from context.

So you could also hear:

• Раз уж дома, позвони бабушке, пожалуйста.

But ты is included here because it sounds more explicit and natural in many everyday situations. It can also add a slight contrastive feeling:

• Раз уж ты дома... = Since you’re the one at home...

So the pronoun is not required, but it is perfectly normal.

Дома means at home.

This is a very common Russian expression:

• Я дома = I’m at home
• Ты дома? = Are you at home?

By contrast, в доме usually means in the house/building, focusing more on being physically inside a building rather than on the idea of being at home.

So:

• ты дома = you are at home
• ты в доме = you are in the house

In this sentence, дома is exactly the usual word to use.

Because позвони is the imperative of the perfective verb позвонить.

• звонить = imperfective
• позвонить = perfective

In commands, Russian often uses the perfective imperative when asking someone to do one complete action:

• Позвони бабушке = Call grandma / Give grandma a call

This suggests a single finished act.

By contrast, звони would more likely suggest:

• call regularly
• keep calling
• be in the habit of calling
• call (with focus on process rather than completion)

So here позвони is the natural choice.

It is the informal singular imperative of позвонить.

Basic pattern:

• infinitive: позвонить
• imperative: позвони

For the plural/formal version, add -те:

• позвоните

So:

• Позвони бабушке = say this to one person you address as ты
• Позвоните бабушке = say this to multiple people or one person you address as вы

Because the verb звонить / позвонить takes the dative case for the person you call.

So:

• позвонить кому? = to call whom?
• бабушка → бабушке (dative singular)

Examples:

• Позвони маме. = Call mom.
• Я позвонил другу. = I called my friend.
• Она звонит сестре. = She is calling her sister.

This is different from English, where call someone uses a direct object. In Russian, the person is in the dative.

In many everyday contexts, бабушка feels closer to grandma than to the more formal grandmother.

So позвони бабушке sounds warm and natural, like:

• Call grandma, please.

Russian often uses family words in a very direct, natural way, without sounding childish.

Пожалуйста makes the command more polite and softer.

Compare:

• Позвони бабушке. = Call grandma.
• Позвони бабушке, пожалуйста. = Please call grandma.

It does not make the sentence highly formal; it just adds ordinary politeness.

In spoken Russian, пожалуйста is very common with requests and suggestions.

The word order is very natural:

• Раз уж ты дома, = sets up the reason/background first
• позвони бабушке, пожалуйста. = then comes the request

So the structure is basically:

Given this situation → here is what you should do.

This mirrors English quite well:

• Since you’re home, call grandma, please.

Russian word order is flexible, but this version sounds smooth and idiomatic.

Yes. The main signal is ты, which is the informal singular form of you.

Also, позвони is the matching informal singular imperative.

A formal or plural version would be:

• Раз уж вы дома, позвоните бабушке, пожалуйста.

So the original sentence is something you would say to:

• a family member
• a friend
• a child
• someone you are on ты terms with

Not necessarily, but it can carry a slight nuance of:

• well, since this is already the situation...
• you might as well...

Depending on tone, it can sound:

• practical
• mildly persuasive
• slightly insistent
• occasionally a bit reproachful

In this sentence, with пожалуйста, it most likely sounds like a normal, gentle request:

• Since you’re home anyway, please call grandma.

So the phrase itself is neutral-to-conversational, and the final tone depends a lot on intonation.