What are Ions?
Many chemical substances dissociate when dissolved in water. When dissociation occurs, the component parts develop charges and are called ions. An ion is an atom or group of atoms which have lost or gained one or more electrons, making them negatively or positively charged.
- Positively charged ions (+) are called cations.
- Negatively charged ions (-) are called anions.
What are Acids?
An acid is any ionic compound that releases hydrogen ions (H+) in solution. Weak acids have a sour taste. Strong acids are highly corrosive.
Examples of acids:
- Ascorbic acid (C6H8O6, Vitamin C)
- Citric acid (C6H8O7, a weak organic acid in citrus.
- Phosphoric acid (H3PO4, in soda pop. This stuff is also used to remove rust…hmmmm.)
What are Bases?
Bases, also called alkaline substances, are ionic compounds that release hydroxyl ions (OH-) in solution. Weak bases have a bitter taste (opposed to sour taste of acids and sweetness of aldehydes and ketones), are slimy to the touch.
Examples of bases:
- Sodium hydroxide, NaOH, of lye or caustic soda used in oven cleaners.
- Magnesium hydroxide, Mg(OH)2, also known as milk of magnesia, a weak base used in antacids and laxatives.
What are Salts?
Compounds that dissociate in water and produce cations other than H+ and anions other than OH- are called salts. One of the salts that we are most familiar with is sodium chloride, the principal component of common table salt.
Other examples of salts:
- Baking soda (NaHCO3)
- Epsom Salts (MgSO4)
What are Buffers?
Certain salts, called buffers, can combine with excess hydrogen (H+) or hydroxyl (OH-) ions to produce substances less acidic or alkaline. Buffers function like chemical sponges that can soak up ions that otherwise would have resulted in changes in pH level.
Great Chemistry Resources
There are many excellent websites to help you better understand chemistry, including Science Daily Matter and Energy Section, SPO’s Inorganic Chemistry Help Page and the Interactive Periodic Table.
Sources
- Campbell, N. and Reece, J. (2005). Biology. Seventh edition. Pearson Education, Inc.
Photo Credit
The photo of chemicals in flasks was taken by Joe Sullivan, originally appearing on Flickr and obtained from Wikipedia.
