A pure substance or chemical substance is a material that has constant composition (is homogeneous) and has consistent properties throughout the sample. Here are examples of pure substances
More About Pure Substances
A pure substance is any single type of material
A substance can be anything. It doesn't have to consist of a single element or type of molecule
Pure hydrogen is a pure substance. So is pure honey, even though it consists of many different types of molecules
If some oxygen is added to the hydrogen, the resulting gas is neither pure hydrogen nor pure oxygen
If corn syrup is added to the honey, we no longer have pure honey
A pure substance is considered to be a material that consists of one type of "building block" of matter
Both elements and compounds can be pure substances, homogenous mixtures are not considered to be pure substances
A substance cannot be separated into components by physical separation methods, i.e. without breaking chemical bonds
A chemical substance can be solid, liquid, gas, or plasma
Chemical substances are often called 'pure' to set them apart from mixtures. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory
Examples of pure substances include tin, sulfur, diamond, water, pure sugar (sucrose), table salt (sodium chloride) and baking soda (sodium bicarbonate)
Tin, sulfur and diamond are examples of pure substances which are chemical elements. All elements are pure substances
Water, sugar, salt and baking soda are pure substances which are chemical compounds. Chemical compounds also are pure substances
Depending on which substances we talk about, homogenous mixtures may be considered examples of pure substances. Examples of homogenous mixtures include vegetable oil, honey and air
In homogenous mixtures are not pure substances. Examples of materials which are not pure substances include gravel, your computer and a tree
We can use melting and boiling points and chromatography to test for pure substances.
Pure substances have a sharply defined (one temperature) melting or boiling point.
If a substance is pure then chromatography will only produce one substance at the end of the process
Methane, carbon monoxide, carbon dioxide, pure water and table salt are examples of _____.
C) Pure substances
D) B and C