Is sour cream a mixture and what other things are heterogeneous?

Answer 1

It depends on the scale: At the macrobiotic scale it is homogeneous, but at the microscopic scale it is heterogeneous because it has active bacterial cultures (like yogurt).

However, commercial sour cream is always heterogeneous because things are added to it. To make it last and improve the taste. The fat content is considered to be a part of the cream, like milk fat is.

According to Wikipedia: http://en.wikipedia.org/wiki/Sour_Cream
"Sour cream is a dairy product rich in fats obtained by fermenting a regular cream by certain kinds of lactic acid bacteria. The bacterial culture, introduced either deliberately or naturally, produces lactic acid, which sours and thickens the cream.

Commercial sour cream, made out of heavy cream, contains from 15 to 20 percent fat, and gets its characteristic tang from the lactic acid created by the bacteria. Sour cream often contains additional ingredients such as gelatin, rennin, and vegetable enzymes.

Light sour cream contains about 40 percent less fat than regular sour cream because it is made from a mixture of milk and cream rather than just cream.

Nonfat sour cream is thickened with stabilizers."

Any material composed of two or more materials (most things) are heterogeneous; to tell if something is heterogeneous or not you need to break it down to the component elements. For example the Statue of Liberty is covered in pure copper, but it has a cast iron superstructure and it uses wood and plastic spaces to keep the copper off the iron--otherwise a adverse chemical reaction would occur.

Almost everything made by man is heterogeneous. Brass Door Knobs have a steel mechanism because it lasts longer. Oil is a mix of hydrogen, carbon and other elements so anything made out of oil will also contain those hydrocarbons making it heterogeneous.

To find a truly homogenous product you need to look at it is composed of down to the elemental level. The only truly heterogeneous materials in existence are pure examples of chemicals from the Periodic Table (http://en.wikipedia.org/wiki/Periodic_Table). This is what you need to look at first. Then you need to think what would happen if the object was allowed to sit and separate. Could it separate? Pure glass is made out of sand, and sand particles are made out of a range of minerals and elements. Most glass has been strengthened or treated with films and advanced material. But, pure glass can be considered homogenous.

EVERY THING is heterogeneous because even pure elements are made up of atoms, which are composed with protons, neutrons, and electrons, which in turn or composed of quarks and leptons. So when your teach asks you if something is homogenous you have to ask her, "On what scale."

Answer 2

Sour cream is a mixture, but it would be called a homogenous mixture. It is like milk, a colloidal mixture. This means it has long molecules, unlike the atoms and ions in solution mixtures, but these molecules are spread evenly throughout the mixture (homogenous), unlike a suspension mixture. Sour cream, along with yogurt, and milk, contains many different types of protein molecules which are not bound to each other, thus making it a mixture. Other things like this are milk, clouds, smoke, jelly, shaving cream. You will notice that a lot of colloids are white and that is because of the large molecules which scatter light independent of wavelength.

Answer 3

Sour cream is homogeneous. A heterogeneous mixture would be like lucky charns.

Answer 4

Usually yes, sour cream is homogenized during processing. The stuff you buy from the grocery store is homogenous.