Properties of Water Essential Questions: What are the properties of Water? What are Mixtures, Solutions and Suspensions? Why is water important for living things?

Introduction to Water Consists of 1 Oxygen atom and 2 Hydrogen atoms per 1 water molecule. How is water bonded? Covalent Bonds Carries substances via Osmosis. Serves as material transportation Blood, plant sap Water makes up 70-95% of organisms. Because of its bonding it can hold large molecules like proteins together. Cycles through the kidneys and eliminated out of the body

Five Major Properties of Water ** Water has three phases: Solid (ice), liquid, gas (vapor)‏** 1. Water is liquid at room temperature, boiling point is high at 100° C; low molecular weight molecules are usually gaseous. - Water resists temperature change (insulator)‏. 2. Water has a high freezing point and ice is less dense than water. (Thus, ice floats in water.) 3. Water is the universal solvent for polar and ionic molecules (means it dissolves things) Hydrophilic: means “water-loving”, molecules that interact with water, soluble in water Hydrophobic: means “water-fearing”, insoluble in water Polar: Means it has a slightly positive (+) end and a slightly negative (-) end.

Five Major Properties of Water 4. Water is sticky: Why? Hydrogen bonds keep water together (polar areas attract) Slightly negative (-) Oxygen end is attracted to the slightly positive (+) Hydrogen ends. Cohesion: attraction of water to other water molecules. Adhesion: attraction of water to other types of molecules. Capillary Action: Can adhere creep up tubes. Examples: - The meniscus in a graduated cylinder. - Water up a tree.

Five Major Properties of Water 5. Water has high surface tension water is more attracted to itself than to the air around it Sticks together (+ and – attract.)

Five Major Properties of Water L U S H REEZING POINT IS HIGH Great insulator! IQUID AT ROOM TEMPERATURE NIVERSAL SOLVENT URFACE TENSION IS HIGH YDROGEN BONDS

Mixtures, Solutions & Suspensions A mixture is a combination of substances where both substances keep their original properties. Physically mixed, not chemically mixed. They can be easily separated. Solution – one or more substances (solutes) are distributed evenly in another substance (solvent) (water)‏ The more solute in a solvent, the higher the concentration. Organisms need to maintain a certain concentration for life processes, called homeostasis. Suspensions – mixtures of water and non dissolved particles Example: Blood Like sugar and salt. Like lemonade. Like blood! Many cells are suspended in blood

Mixtures, Solutions & Suspensions A mixture is a combination of substances where both substances keep their original properties. Physically mixed, not chemically mixed. They can be easily separated. Solution – one or more substances (solutes) are distributed evenly in another substance (solvent) (water)‏ The more solute in a solvent, the higher the concentration. Organisms need to maintain a certain concentration for life processes, called homeostasis. Suspensions – mixtures of water and non dissolved particles Example: Blood Water and salt– Solution Sand and water – Suspension Sand and shells – Mixture

Homeostasis The ability or tendency of an organism to maintain internal equilibrium, or balance, internally. Think back to the kidneys… If we are dehydrated, our kidneys keep water! If we are hydrated, our kidneys lose the excess water!