HSC BIOLOGY ASSESSMENT TASK 1
MAINTAINING A BALANCE
TASK: OPEN-ENDED INVESTIGATION
Our task is to plan, choose equipment and perform a first hand investigation to demonstrate the effect of dissolved carbon dioxide on the pH of water.
DUE DATE: 21/11/07
CONDUCTOR: Wissam Bardouh
EFFECT OF DISSOLVED CARBON DIOXIDE (CO2) ON PH OF WATER
((Carbon Dioxide is a greenhouse gas. It is everywhere ranging from our bodies to the atmosphere. Carbon dioxide is produced in living organisms as a result of cellular respiration (glucose + oxygen -->carbon dioxide + water + energy). It occurs in high concentrations in the tissues in our body. It then diffuses in the circulatory system where it may be carried in our blood))3. When this blood combines with water and then dissolves, Carbonic acid (hydrogen carbonate ions + hydrogen ions). are formed in the red blood cells which are then carried in the plasma. ((CO2 + H2O --> H2CO3))1. This dissolved carbon dioxide can easily change the pH of water. This carbonic acid is toxic to cells and therefore, whenever carbon dioxide is produced, the body tries to get rid of it before chemical activities are disturbed.
pH is a measurement of how acidic or basic a solution is. Water with pH lower than 7 is considered acidic and higher than 7 is known as basic. The safe levels of pH in drinking water is 6.5 - 8.5. Pure water has a pH of 7 which means there is an equilibrium of positive hydrogen ions and negative hydroxide ions. ((When the pH of water is below 6.5, the water is soft and corrosive. This type of water can damage metal pipes and when used, it can stain clothes, have a sour taste and damage sinks. Water with a Ph greater than 8.5 is considered hard. This water does not pose a health risk, but can stain dishes and utensils))4. When Ph of water is low there can be many consequences and effects. ((Even a moderate decrease in pH of water could affect the fish