Notes i. oxygen and ozone - 2010Presentation Transcript
I. Oxygen and Ozone
Objectives: know the names and formulas of oxygen and ozone. define allotrope. know the structure, properties, and occurrence of oxygen and ozone.
I. Oxygen and Ozone There are two types of oxygen molecules that exist in the earth’s atmosphere: 1. molecules of 2 oxygen atoms – O2 called oxygen 2. molecules of 3 oxygen atoms – O3 called ozone
I. Oxygen and Ozone O2 and O3 are allotropes of the element oxygen. allotrope – one of two ore more forms of an element that have the same physical state
I. Oxygen and Ozone Structure of oxygen – O2: Most oxygen exists in the form of diatomic molecules (two oxygen atoms double covalently bonded together). Diatomic oxygen molecules have a linear shape.
I. Oxygen and Ozone 2. Properties of oxygen – O2: Colorless, odorless, and tasteless gas. Oxygen reacts with many metals to form oxides. oxide - ionic compound containing the O-2 ion
I. Oxygen and Ozone Occurrence of oxygen – O2: Oxygen makes up approximately 21 % by volume of the air we breathe. Oxygen is the most abundant element by mass in the earth’s crust, waters, and atmosphere. (*Hydrogen is the most abundant element by number of atoms.)
I. Oxygen and Ozone Structure of ozone – O3: Ozone molecules consist of 3 oxygen atoms covalently bonded together. Ozone molecules have a bent shape.
I. Oxygen and Ozone Properties of ozone – O3: O3 at ground level (bad) - poisonous blue gas with a pungent odor; constituent of smog; harmful to plant tissue and lungs
I. Oxygen and Ozone Occurrence of ozone – O3: O3 in the upper atmosphere (good) – ozone molecules absorb harmful uv radiation from the sun; ozone acts as the Earth’s natural sunscreen Over 90% of ozone naturally occurs in the upper atmosphere. The ozone in the upper atmosphere is referred to as the ozone layer.