Compound
A substance made of two or more different elements joined together by chemical bonds. It can only be split up by a chemical reaction.
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Analogy
A compound is like a cake. You cannot pick the flour and eggs back out once it is baked.
Example
H2O: 2 hydrogen, 1 oxygenCO2: 1 carbon, 2 oxygenNaCl: 1 sodium, 1 chlorine
In practice
Water is a compound of hydrogen and oxygen. Its formula is H2O.
Practice
Flashcards
- What is the difference between a compound and a mixture?A compound has its elements chemically joined. A mixture is not chemically joined and can be separated physically.
Interview questions
- Describe the difference between an element, a compound and a mixture, with one example of each.
- Element has one type of atom
- Compound has different atoms chemically bonded
- Mixture is not chemically bonded
- Mixtures can be separated physically
Questions people ask
Why does a compound look different from the elements in it?
When elements bond, their atoms rearrange and share or swap electrons. That creates a new substance with new properties. Sodium is a soft, explosive metal and chlorine is a poisonous gas, yet together they form table salt, which is safe to eat.
How do you write the formula for a compound?
A formula uses symbols and small numbers to show how many atoms of each element are in one unit. In H2O the 2 sits after H and means two hydrogen atoms. No number means one atom. So CO2 has one carbon and two oxygen atoms.