На полке стоит банка варенья, а рядом лежит пачка чая.

Because after на when you mean a fixed location, Russian uses the prepositional case.

• полка = shelf
• на полке = on the shelf

Compare:

• на полке = on the shelf, located there
• на полку = onto the shelf, movement toward it

So in this sentence, the jar is already there, so на полке is correct.

Russian often uses position verbs where English would simply say is.

• стоять = to stand
• лежать = to lie
• висеть = to hang

So:

• банка стоит because a jar is normally imagined as standing upright
• пачка лежит because a pack is often imagined as lying flat

In English, we usually just say There is a jar... and a pack..., but Russian is more specific about physical position.

Yes, if the speaker imagines the pack as upright.

Russian chooses verbs like стоять and лежать based on how the object is positioned.

So both can be possible in different situations:

• На полке стоит пачка чая = the pack is standing upright
• На полке лежит пачка чая = the pack is lying flat

In your sentence, лежит suggests the packet is lying down.

They are in the genitive case because Russian often puts the contents of a container or package in the genitive.

• банка варенья = a jar of jam
• пачка чая = a pack of tea

This is a very common pattern:

• чашка кофе = a cup of coffee
• бутылка воды = a bottle of water
• килограмм сахара = a kilogram of sugar

So варенья and чая are not random forms; they are exactly what Russian normally uses after words like банка and пачка.

In this sentence, а does not mean a strong but. It often marks a mild contrast or a shift from one item to another.

So:

• ..., а рядом лежит ... = ..., and nearby there is/lies ...

It sounds natural because the speaker first mentions one object, then adds another object in a slightly different position.

Very roughly:

• и = simple and
• а = and / while / whereas, with a sense of contrast or separate focus

Here а is a very normal choice.

Рядом means nearby, next to it, or beside it.

In this sentence, it works as an adverb, so it can stand alone:

• рядом лежит пачка чая = nearby / next to it lies a pack of tea

If you want to say explicitly what something is next to, Russian usually uses:

• рядом с + instrumental

For example:

• рядом с банкой = next to the jar

But in your sentence, that noun is omitted because the context already makes it clear.

Russian word order is flexible, and different orders give different emphasis.

• На полке стоит банка варенья starts with the location. It feels like On the shelf, there is a jar of jam
• Банка варенья стоит на полке starts with the jar itself. It feels more like The jar of jam is on the shelf

In your sentence, the location is presented first, which is very natural when describing what is where.

Also, putting the verb before the noun often helps introduce a new object into the scene.

Russian often does not use a separate present-tense verb to be the way English does.

Instead, Russian commonly expresses existence through:

• word order
• context
• other verbs such as стоять, лежать, висеть

So instead of a literal There is a jar on the shelf, Russian naturally says:

• На полке стоит банка варенья

This is one of the most important differences between English and Russian sentence structure.

Because each verb belongs to its own clause and agrees with a singular subject:

• стоит банка = банка is singular
• лежит пачка = пачка is singular

The whole sentence has two separate parts joined by а:

1. На полке стоит банка варенья
2. рядом лежит пачка чая

Each part has one singular noun, so each verb is singular.

Yes, you can, but the structure is slightly different.

• банка варенья = a jar of jam
• банка с вареньем = a jar with jam in it

The first version is the more basic and common container + contents pattern.

The second version is also correct, but it can feel a bit more descriptive, as if you are emphasizing that the jar contains jam.

For this sentence, банка варенья is the most straightforward and natural choice.

Russian has no articles.

So Russian does not directly mark the difference between:

• a jar
• the jar

Instead, Russian shows that through:

• context
• word order
• intonation
• sometimes extra words if needed

In this sentence, English needs a jar and a pack, but Russian simply says:

• банка
• пачка

The listener understands from context whether the meaning is indefinite or definite.

Because а joins two clauses, and Russian normally puts a comma before coordinating conjunctions like а when they connect separate parts with their own verbs.

Here the clauses are:

• На полке стоит банка варенья
• а рядом лежит пачка чая

Each clause has its own verb, so the comma is required.