What is it and how does it work? Water What is it and how does it work?

What Do We Know About Water? Water in its purest form is: Colorless Odorless Tasteless All forms of life need it, and if they don’t get enough of it, they die.

What Is The Composition Of Water Water is a molecule with one oxygen atom and two hydrogen atoms, bonded together by shared electrons. It is a V shaped molecule, which means that its charged positively near the hydrogen atom, and negatively near the oxygen atom.

Polarity Of Water Molecules Water molecules are naturally attracted and stick to each other because of its polarity, forming a hydrogen bond. Polarity happens when a shared pair of electrons in a covalent bond are not shared equally.

Hydrogen Bonding A hydrogen bond is a bond between a hydrogen atom that covalently bonds to a highly electronegative atom such as Oxygen, Nitrogen, or Fluorine.

Explain why water is a polar molecule. Stop and Think If you were to observe a small amount of water, how could you describe it? Write three sentences on your observations. Explain why water is a polar molecule. Describe the type of bond that holds the water molecule together.

Electronegativity Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons.

Properties Of Water Many of water’s special properties can be attributed to the hydrogen bonds holding the molecule together. Some of water’s properties include: Cohesion Adhesion Surface Tension Capillary Action Density (solid and liquid form) Specific Heat Capacity Heat of Vaporization

Water In Solution Water is also known as the universal solvent, which means that it can dissolve many substances. Substances that dissolve in water are hydrophilic Substances that do not dissolve in water are hydrophobic Water is rarely pure because of its solvency, there are always some type of mineral naturally occurring in water.

Stop and Think 4. What properties of an atom do you think allows it to have a high electronegativity? 5. Use a Chemistry textbook to define the following properties of water, Cohesion,Adhesion,Surface Tension,Capillary Action, Density (solid/liquid), Specific heat capacity, Heat of Vaporization 6. What is the difference between hydrophobic and hydrophilic substances?

Why Do We Need Water Electrolytes, which are minerals such as sodium and potassium that regulate the body’s fluids are lost every time water leaves the body in the form of sweat, exhalation, or excretion.

Water On The Earth The water cycle or Hydrologic Cycle is the continuous movement of water in and around the earth.

8. Describe each step of the water cycle. Stop and Think 7. Explain why water is important to the human body. 8. Describe each step of the water cycle. 9. Explain why it is often necessary to purify water for drinking purposes.