Metals in Medicine

Carbonate - Why Are Fizzy Drinks Bad for our Teeth?

Carbonate is harmless, we drink it in fizzy drinks. Carbon dioxide is one of the gases in air that we breathe, and when it dissolves in water, carbonate ions are produced.

Equation showing the reaction of Carbon Dioxide with water

A solution of carbon dioxide in water is acidic and so contributes to the acidity of fizzy drinks. This acid together with the sugar makes fizzy drinks doubly bad for our teeth!

The acidity of carbon dioxide can be demonstrated by putting frozen carbon dioxide (DRY ICE) into water containing Universal indicator. Universal indicator changes colour if you add an acid to it.

Experiment showing that Carbon Dioxide is Acidic

Frozen carbon dioxide (1) ('dry ice') has a temperature of -78 °C. A beaker of water and Universal Indicator (2). Water is neutral so the indicator is GREEN. Dry ice is added to a beaker of water and Universal Indicator (3). Once dry ice is added (4) the indicator immediately changes to RED showing that the carbon dioxide dissolved in water is acidic. A lot of gas is produced as the solid dry ice turns into gas when it contacts the warm water.

Dry ice is very cold (-78 °C) and at atmospheric pressure it does not have a liquid phase. Therefore it changes straight from a solid to a gas as it warms up. This is called SUBLIMATION. Not having a liquid phase makes dry ice very useful for transporting goods which need to be keep cold. Unlike water ice, the lack of liquid phase means that the goods won't get wet.

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Metals Are Essential for Life - Lithium treats mental illness - Carbonate - Why Are Fizzy Drinks Bad for our Teeth? - Iron compounds are essential to life - Iron Makes Our blood red - How Do We Get Energy From Oxygen? - Iron is Used to Make Steel - Platinum is Used in Treating Cancer - Cis and Trans? - Titanium is used to make hip replacements - Barium is used to see inside our bodies - Lead: a toxic metal that protects us from x-rays

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