Question

Which of the following describes a heterogeneous mixture?

Answer 1

It can be separated by chemical means but not by physical means.

It cannot be separated by either chemical or physical means.

It can be separated by physical means and is uniform in composition.

It can be separated by physical means and is not uniform in composition.

Answer 2

Tell me the definition of a heterogeneous mixture, according to your understanding?

Answer 3

A mixture in which the composition and properties are not uniform throughout the mixture.

Answer 4

Good, how do you separate all those component?

Answer 5

You've defined "heterogenous" but not "mixture." How does a mixture differ from a compound? That is the remaining key.

Answer 6

Mixture: A combination of two or more substances, each retaining its individual composition and properties.

Answer 7

That's what I have in my notes.

Answer 8

Well, if it's heterogenous and it's a MIXTURE, then you can separate it's composition, although they would not be uniform, there would still be some leftover of other substances in the substance you collected.

Answer 9

SO C?

Answer 10

Read my post again.

Answer 11

A?

Answer 12

http://puu.sh/Fl6K

Answer 13

But what about the physical?!

Answer 14

D???????

Answer 15

D is right.

Answer 16

If you ever want to separate chalk powder from water, you wouldn't go with a chemical reaction, you'll do it physically, and there will be some leftover of chalk in the water, undissolved, but no uniform.

Answer 17

Huh. Those are not the most helpful definitions. Fire your teacher, ha ha. Anyway, the distinction between mixtures and compounds, and by extension physical and chemical means of separation, can really only be logically addressed at the atomic level. Generations of chemistry teachers have attempted to do so purely macroscopically, but it's futile and silly. The best minds of antiquity were unable to clearly disttinguish chemical and physical separation, and hence comopunds and mixtures, without the concept of atoms. Indeed, atoms were pondered as a fundamental constituent of matter precisely BECAUSE their existence rationalized the whole mess of mxture/compound and chemical/physical separation.

So here we go: a COMPOUND is, in general, a pure substance made of molecules (or ions in a characteristic pattern) -- different types of atoms joined together by chemical bonds (or very strong electrostatic attractions in a particular pattern). A MIXTURE is a substance made of different types of atoms, or molecules. A mixture of hydrogen and oxygen gas contains H2 molecules and O2 molecules. Water gas, also made of hydrogen and oxygen, consists of H2O molecules. (Two hydrogen atoms bonded to an oxygen atom.)

Now, PHYSICAL means of separation are any means that do NOT involve breaking or making chemical bonds. CHEMICAL means of separation are any that do. To separate they hydrogen and oxygen in a mixture of the two gases, you need not break any chemical bonds. To separate the hydrogen and oxygen in a bunch of water vapor, you do. You can use physical means to accomplish the first, but the second requires chemical means. So your homogenous mixture can be separated by physical means -- filtering, distilling, washing by solvents, et cetera and so forth. You've already recognized that "homogenous' means that its composition does not vary from place to place.

Answer 18

Hire this guy ^