General Science questions!!!!!!?

Question

Is gasoline a pure substance, a homogenous mixture, or heterogeneous mixture? Explain..


If pure gold is classified as 24-karat gold, then 10-karat gold must be a _____________ mixture.
a. homogeneous b. Heterogeneous

Answer 1

Gasoline is homogenous. It does not separate like oil & water if left alone for a period of time.

The same with gold.

Answer 2

Homogenous and Heterogeneous

Basically a Homogenous substance is one that is all the same; the killer word here is "pure." Anything that is pure is 99.99% of the time homogeneous. A homogeneous substance is a pure substance; whatever that substance is, even if it is a complex substance.

Heterogeneous is a mix, more than one. So if 24-karat is pure then 10-karat must be impure. The key is the word impure; anything that is impure is 100% of the time heterogeneous. In the case of gold usually silver is added to make it less gold; so called “white gold” is a mix of gold and silver, 10-karat gold is most likely “white gold.” The key word here is “mix” if a substance is a mix then it is heterogeneous.

A cake mix uses flour, water, salt… that makes it a heterogeneous substance. Gasoline is a hydrocarbon that is composed of various elements including carbon and hydrogen (hence it is called a hydrocarbon). It is a bunch of elements, but it is NOT a mix of elements; the elements are combined.

You almost never see pure acid. Acids work best with water so they are diluted. Acids are also safer when highly diluted. So while H2S04 may be sulfuric acid and a pure substance, you almost never find pure sulfuric acid in a lab. It is almost always diluted with some pure water which makes it a heterogeneous substance. If you put two pure substances together then you have a mix and any mix = heterogeneous.

The idea here is can you find some of one thing and some of another. If you mix your cake mix very well then your are going to still have pockets of flour that are not wet. As the batter thickens then the water content drops. You don’t have to liquefy a cake mix before cooking it, as long as you mix it pretty well you will have done enough. If you ran your cake mix through a blender and then looked at it under a microscope then you could still find tiny bits of dry flour, bits of egg, salt crystal and whatever else is in the mix. This is why it is heterogeneous.

If you look at pure gasoline under a microscope then you will still have pure gasoline. You would have to break it apart to not be pure and doing that would mean that it wouldn’t be gasoline anymore; it would be gasoline plus something else; that would then change it from homogenous to heterogeneous. Therefore any chemical substance that can be called pure is homogenous.

Your pure gasoline is homogenous because if you can use the word “pure” then you will have a homogenous substance. Gasoline is not a mix, it is a single substance. A cake mix is a combination of things so it is a mix. Pure water is homogenous (again the word is pure). Distilled water is homogenous; it has been put through a process to make it pure. Sea water is heterogeneous, because it is salt water. The salt is dissolved in the sea water; but if you looked at it under a microscope you would see some salt crystals. If you see more than one thing it becomes heterogeneous. Tap water is heterogeneous, chlorine is added to clean it and fluorine is added to help our teeth. A water filter can take out most of the impurities, but unless the water is really pure it is still heterogeneous. Distilled water uses a series of filters or other means to remove the other things in it thus making it a homogenous substance. We all know that water is H20; a combination of two hydrogen atoms and one oxygen atom. Joined together they become a molecule of water. A molecule is homogenous and that is the point that makes the key difference. If you only have one type of molecule then you have a pure or homogenous substance. When you add water to flour and yeast you get a chemical reaction that creates the cake. The mix creates new molecules of cake substance, but there are other things inside that don’t change and there will always be a little left over yeast. That means a cake can never be homogeneous it is always heterogeneous. You can say the same thing about salt water and any other heterogeneous substance.

Answer 3

a