Zużyte urządzenie jest elektroodpadem.

Because zużyte is an adjective describing urządzenie, and in Polish adjectives must agree with the noun in gender, number, and case.

Here, urządzenie is:

• singular
• neuter
• in the nominative case

So the adjective also has the singular neuter nominative form:

• zużyty = masculine
• zużyta = feminine
• zużyte = neuter

So:

• zużyty telefon = a worn-out phone
• zużyta lodówka = a worn-out fridge
• zużyte urządzenie = a worn-out device

Not quite. Zużyte usually means used up, worn out, spent, or no longer fit for normal use.

That is important here. Zużyte urządzenie is not just a device that someone has used before. It suggests a device that has reached the end of its useful life.

Compare:

• używane urządzenie = a used device, second-hand device
• zużyte urządzenie = a worn-out / end-of-life device

So in this sentence, zużyte fits the idea of something that should now be treated as electronic waste.

Urządzenie is a neuter noun meaning device, appliance, or piece of equipment, depending on context.

It comes from the verb urządzić / urządzać, but as a noun it simply means a thing like a machine or technical device.

Examples:

• urządzenie elektryczne = an electrical device
• nowe urządzenie = a new device
• to urządzenie = this device

Because it ends in -enie, it is very often neuter, which is why you get:

• to urządzenie
• zużyte urządzenie

Because after być (to be), Polish very often uses the instrumental case for a predicate noun.

So:

• dictionary form: elektroodpad
• instrumental singular: elektroodpadem

That is why the sentence says:

• Zużyte urządzenie jest elektroodpadem.

This is a very common pattern in Polish:

• On jest nauczycielem. = He is a teacher.
• To jest problemem. = This is a problem.
• Zużyte urządzenie jest elektroodpadem. = A worn-out device is e-waste.

You may sometimes see nominative after to in identifying sentences, for example:

• To jest elektroodpad.

But in a normal sentence with jest, the instrumental elektroodpadem is very natural and standard.

It is the instrumental singular.

The base form is:

• elektroodpad = e-waste / electronic waste item

Instrumental singular:

• elektroodpadem

The ending -em is a very common instrumental singular ending for masculine and neuter nouns.

More examples:

• komputer → komputerem
• problem → problemem
• odpad → odpadem
• elektroodpad → elektroodpadem

Yes, it is one word: elektroodpad.

It is built from:

• elektro- = electric / electronic
• odpad = waste

So literally it is something like electro-waste, which corresponds to electronic waste or e-waste in English.

Polish often forms compounds like this, especially in technical or environmental language.

Yes. Polish word order is more flexible than English word order, because the endings carry a lot of grammatical information.

The neutral order here is:

• Zużyte urządzenie jest elektroodpadem.

But you could also see:

• Elektroodpadem jest zużyte urządzenie.

That version puts more focus on elektroodpadem.

Even so, the original sentence sounds the most neutral and straightforward in most contexts.

Because Polish has no articles like a, an, or the.

So where English says:

• A worn-out device is electronic waste
• The worn-out device is electronic waste

Polish can simply say:

• Zużyte urządzenie jest elektroodpadem.

Whether it feels more like a or the depends on context.

A rough guide for an English speaker:

• zużyte ≈ zoo-ZHI-teh
• urządzenie ≈ oo-zhon-DZEH-nyeh
• jest ≈ yest
• elektroodpadem ≈ eh-lek-tro-ot-PAH-dem

A few useful pronunciation notes:

• ż sounds like the s in measure
• rz often sounds the same as ż
• dz is like ds said together, and in dzenie it becomes a soft sound
• Polish stress is usually on the second-to-last syllable:
  • zu-ŻY-te
  • u-rzą-DZE-nie
  • e-lek-tro-od-PA-dem

Yes, often you could.

Sprzęt means equipment or gear, and in some contexts it can sound more general or more natural than urządzenie.

Compare:

• zużyte urządzenie = a worn-out device / appliance
• zużyty sprzęt = worn-out equipment / hardware

But there are two grammatical differences:

1. sprzęt is masculine, so the adjective changes:
   • zużyty sprzęt
2. The rest of the sentence stays the same:
   • Zużyty sprzęt jest elektroodpadem.

So yes, it is possible, but it is not exactly the same nuance.

It can do either, depending on context.

Without articles, Polish often leaves that open. So this sentence can mean:

• A worn-out device is e-waste — a general statement
• The worn-out device is e-waste — referring to a specific item already known in context

If Polish wanted to be more clearly general, it might also use a plural or another phrasing, but your sentence works well as a general rule or classification statement.