Chemical Elements and Water Shaun Daniels & John Depass

Outcomes State that:  The most frequently occurring chemical elements in living things are Carbon, Hydrogen, Oxygen and Nitrogen

3.1.2 State that:  A variety of other elements are needed by living organisms, including sulfur, calcium, phosphorus, iron and sodium

3.1.3 A role of each element:  Sulfur: Found in some Amino Acids.  Calcium: Is found in the bones and teeth of animals. Essential in synaptic transmission.  Phosphorus: Is essential in the formation of the phospholipid bilayer (cell membrane).  Sodium: Sodium is the main cation in blood plasma

Show the structure of water molecules (3.1.4):  Positive Hydrogen bonds with the negative Oxygen.

3.1.5 Outline the Thermal, Cohesive, and Solvent properties of water Solvent & Thermal Properties: Animation ofwater/water.swf ₪ Water is Polar, which allows it do dissolve almost all substances (Universal Solvent) ₪ Water has a high specific heat, meaning, it takes a lot of energy to change water’s state.

Cohesion:  Water molecules stick together through Hydrogen Bonding (Cohesion). Water can also stick to other surfaces (Adhesion).  Since water molecules stick together, they form surface tension, allowing some organisms to walk on them.  Surface tension also allows water droplets to form.

3.1.6 Water as a coolant:  Water’s thermal properties allow it to remain at a relatively constant temperature throughout the seasons.  Water is used to cool off our bodies through sweat. When the sweat evaporates off of the skin, it causes a cooling sensation, which cools the body.

Water as a medium for metabolic reactions: Going back to water’s solvent properties, once a substance is diffused, the particles are able to move around freely. This increases the chances that they will collide, leading to a reaction.

Water as a transport medium: Water is dense. This allows water to support the mass of large and small organisms. Smaller organisms would float, larger organisms can swim. Water can transport molecules across membranes (diffusion).

That’s all ya need to know…