Definition Of Pure Substances
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