270 likes | 377 Views
Water. By Neil Bronks. Water is important. 70% of the earth 89% of the human body Only 3% is fresh and most of that is in the polar ice caps. Water is a compound. Chemically bonded atoms of Oxygen and Hydrogen. H. O. O. O. H. H. H. H. O. H. H. H. 2H 2 + O 2 2H 2 O.
E N D
Water By Neil Bronks
Water is important • 70% of the earth • 89% of the human body • Only 3% is fresh and most of that is in the polar ice caps
Water is a compound • Chemically bonded atoms of Oxygen and Hydrogen H O O O H H H H O H H H 2H2 + O2 2H2O
Ice Floats • Most substances contract and get denser as they become a solid More dense solid sinks
Ice Floats • Ice expands and so floats on water. • Lucky for us Less dense solid floats
Water Treatment Screening - Clean water passes through the screen and large objects do not
Sedimentation • Alum (Aluminium Sulphate) is added that makes all the dirt stick together. • Most sinks
Add Chlorine Cl • Kills the bacteria
Add Fluorine F • Prevents tooth decay
Water Treatment Screening - Clean water passes through the screen and large objects do not pass Sedimentation - Aluminium Sulphate is added. It is mixed slowly and then allowed to settle. Filtration – passes through sand Add chlorine to kill bacteria. Add flourine to prevent tooth decay.
Desalination • Removing salt Stone Clear Plastic Sea Water Pure Water
Electrolysis of Water Water separated into gases using electricity Some acid must be added to increase conduction
Algal Bloom • Too much fertiliser or food waste can feed algae causing a harmful algal bloom • This uses up all the oxygen and kills fish
Add Soap solution Add Soap solution Hard and soft water • Add soap and mix Soft Water Lots of Bubbles Hard Water Few Bubbles Oily scum
Hard Water • Contains dissolved calcium and magnesium ions • Forms scum when soap is used • Scale on inside of pipes and kettles
Where hard water comes from Acid Rain Limestone Water that runs off straight to rivers and lakes is soft water Water dissolves the limestone (Calcium Carbonate) and the calcium ions make the water hard
Removing Hardness from water • Distillation • Ion exchange with Zeolite resins • Soft water better for industry and plumbing • Hard water better for your heart
H/w P 250 Q 1,2,4,5,6,8.