What's the difference between a piece of and a bar of? A bar of soap is a piece of cheese. Why use piece and bar separately?

A piece of
Such as a piece of paper
Loaf a loaf of bread
Bar, bar
Bar itself means bar or bar, so it is usually used to describe long bar or bar like objects
Piece has the meaning of piece, block, piece and part, which is widely used. Many uncountable nouns can be described by piece
The uncountable nouns modified by bar can be replaced by piece
On the contrary, not every piece of uncountable nouns can be modified with bar
Piece is more widely used than bar
So a picec of soap is OK

RELATED INFORMATIONS

1. A piece of cheese is a piece of cheese, so is a loaf of cheese also a piece of cheese? Is there any difference between piece and loaf? So why is a piece of bread a loaf of bread? And bar
2. The usage of piece or a piece of When an adjective modifies piece or a piece of, where is the position of the adjective? For example, translation: a piece of good news or a piece of good news I looked it up in the Oxford Dictionary, for example, a large piece of land. An interesting piece of research. But I'm still not sure where the adjectives are. Hope that high-level experts can have a detailed answer with examples.
3. Do loaf and bread mean bread? Why can they be used together? Some use a piece of bread, some use a loaf of bread
4. Which is right, a carton of milk or a box of milk? In a multiple-choice question, there is such a question: I always have ____ ,an egg,two pieces of bread for my breakfast. A.a milk B.a carton of milk C.two packet of milk D.a box of milk B. Some are d. which is right? What is the reason? (only one answer)
5. Is it a carton of milk or a bottle of milk? Why am I writing a bottle of milk wrong? milk
6. I'd like a carton of milk. Ask to change into general questions, to quickly
7. There is a box of milk on the table?
8. What is a loaf of bread like? What about a slice of bread?
9. What does this of mean?
10. I want two loaf of bread
11. What's the difference between piece; loaf; bar? The more specific the better, always confused. I know the meaning, but what is the specific distinction The one below, I know what it means. I can find these everywhere. Will I come here to ask? The main reason is that they can't be distinguished. In English, they are different! What I want is a clearer distinction. I already know what you said. I understand the meaning, but both piece and bar can be used to express block
12. What's the difference between bar and loaf,
13. A cup of coffee
14. The price of a cup of coffee is lighter than ___ How to use the answer that
15. _______ a glass of coffee. A I have B I'd rather have C I prefer to
16. would you like a cup of coffee?______ .I would like a glass of water. A、No,thank you B、No,I would not C、Yes,I would D、Yes,please
17. A:Would you like something to drink?( )a cup of tea?B:No,( ).I'd like a glass of milk. A:Would you like something to drink?( )a cup of tea? B:No,( ).I'd like a glass of milk. A:Would you like something to( B:Some bread,please. A:All right.Here you are. B:Thank you. A:( )
18. I（）a glass of milk What to fill in? 1.would like 2.could like 3.can like 4.am like
19. Please have a cup of milk
20. Please translate the following into English phrases Protect sb. From Encourage someone to do it. Realize that .