Власть требует ответственности.

Because требовать normally takes the genitive case, not the accusative.

So:

• ответственность = nominative singular, the dictionary form
• ответственности = genitive singular here

In this sentence:

• власть = the subject, so it stays in the nominative
• требует ответственности = demands responsibility / requires responsibility

This is a very common pattern in Russian:

• требовать помощи = to demand help
• требовать ответа = to demand an answer
• требовать внимания = to demand attention

So the key thing to remember is: требовать + genitive.

Власть is in the nominative singular, because it is the subject of the sentence — the thing doing the requiring.

You can see the sentence structure as:

• Власть = subject
• требует = verb
• ответственности = object in the genitive

Even though English often uses a direct object after require, Russian uses a different pattern here.

Требует is the 3rd person singular present-tense form of требовать.

That means it matches a singular subject such as власть.

A quick breakdown:

• я требую = I demand
• ты требуешь = you demand
• он / она требует = he / she demands
• власть требует = power / authority demands

So требует can mean demands or requires, depending on context.

Here it is genitive singular.

That is worth noticing because the form ответственности can represent more than one grammatical possibility in Russian, including:

• genitive singular
• dative singular
• prepositional singular
• nominative plural
• accusative plural

But in this sentence, after требует, the expected case is genitive, so the natural reading is genitive singular.

In Russian, a noun ending in ь can be either masculine or feminine, so you cannot tell the gender from ь alone.

Власть is a feminine noun. It belongs to the group of feminine nouns ending in a soft sign, such as:

• власть
• ночь
• мысль

That is why, if you used it with a past-tense verb, the verb would also be feminine:

• Власть требовала ответственности. = Authority demanded responsibility.

Yes. Russian word order is flexible because case endings show the grammatical roles.

The neutral order here is:

• Власть требует ответственности.

But you could also say:

• Ответственности требует власть.

That still means essentially the same thing, but the emphasis changes. This version highlights ответственности more strongly, as if saying It is responsibility that power demands.

So:

• normal, neutral statement: Власть требует ответственности
• stronger focus on responsibility: Ответственности требует власть

Russian has no articles.

So власть can mean:

• power
• the power
• authority
• the authority
• sometimes even the government / those in power, depending on context

And ответственности can be understood as responsibility without needing an article.

Russian usually leaves that kind of definiteness to context.

The stress is:

• власть
• тре́бует
• отве́тственности

So the whole sentence is:

Власть тре́бует отве́тственности.

A rough pronunciation guide for an English speaker could be:

vlast' TRYE-boo-yet at-VYET-stven-nas-ti

A couple of useful notes:

• власть ends with a soft consonant
• тре́бует has the stress on the first syllable
• отве́тственности also has the stress near the beginning, on ве

For practical learning, it is best to memorize it as a verb pattern:

• требовать чего? = to demand / require what? in the genitive

Russian has many verbs whose case pattern does not match English. So instead of learning only the meaning требовать = to demand, learn the whole package:

• требовать + genitive

That will help you produce correct Russian much faster.

For example:

• требовать помощи
• требовать объяснения
• требовать уважения

This is one of those places where memorizing the verb together with its case government is very useful.