CHEM CHPT 3

Decomposition of ozone to oxygen occurs as a series of radical reactions. The individual reactions in this series are listed below in the correct order.

1. FClClFC 2. 2Cl• + 2O3 --> 2Cl• + 2O2 3. 2ClO• --> ClOOCl 4. ClOOCl (UV photon) ClOOCl 5.ClOO --> Cl + O2

Place the events of the history of ozone depletion in chronological order.

1930 - Chlorofluorocarbons (CFC's) are invented and used as propellants and refrigerants by people worldwide. 1974 - F. Sherwood Rowland, Mario Molina and Paul Cruzen discover that CFCs are a major cause of stratospheric ozone depletion. 1977 - The United Nations meets and adopts the World Plan of Action on the Ozone Layer. 1978 - The US and Canada ban the use of CFCs in spray cans. 1987 - The Montreal Protocol on Substances That Deplete the Ozone Layer is signed and ratified by countries worldwide. 1990 to present - Production and use of CFCs and other ozone depleting agents dramatically decreases.

Calculate the wavelength of a wave with velocity of 5.1 x 10^4 ms and frequency of 1.1 x 10^8 s^-1.

4.6 x 10^-4 m

Consider the Bohr model of an atom, in which electrons reside in energy levels, denoted as n, starting from nearby the nucleus (n = 1) to farther away from the nucleus (n = 3). Which of the following electronic transitions would result in the emission of light with the shortest wavelength?

An electron moving from the n = 3 level to n = 1.

A substance must be radioactive in order for it to emit radiation.

FALSE: For instance, UV light from the sun is not radioactive, but it is considered a type of radiation.

True or False: For an electron to "jump" from a lower energy level to a higher one, energy must be emitted by the electron.

False. For an electron to move from a lower-energy to higher-energy state, energy must be absorbed, not emitted.

The ____ of a wave is the number of wave cycles per second.

Frequency

Place types of electromagnetic radiation listed below in order from shortest wavelengths to longest.

Gamma Rays X-rays UV-Visible Infrared (IR) Microwave Radio Waves

Electromagnetic radiation consists of particles called PHOTONS, each of which has a discrete amount or quantum of energy. However, since electromagnetic radiation also has wave properties, each particle is also characterized by a specific WAVELENGTH and frequency

PHOTONS WAVELENGTH

Electromagnetic radiation consists of particles called ____. Each of which has a discrete amount, or quantum, of energy. However, since electromagnetic radiation also has wave properties, each particle is also characterized by a specific ____ and frequency.

Photons Wavelength or Energy

Place types of electromagnetic radiation listed below in order from lowest energy to highest energy.

Radio Waves Microwaves Infrared (IR) UV-Visible X-rays Gamma Rays

Label the diagram below with the different types of electromagnetic radiation in the EM spectrum.

Radio Waves ~ >10^-1 m Microwaves ~ 10^-3 to 10^-1 m Infrared (IR) ~ 10^-6 to 10^-3 m Visible ~ 10^-7 m UV ~ 10^-7 to 10^-8 m X-rays ~ 10^-8 to 10^-12 m Gamma Rays ~ <10^-12 m

During photosynthesis ____.

Sunlight is converted into stored chemical potential energy. CO2 and H2O are consumed to produce glucose.

Which of the following statements correctly describe a photon? All these apply.

The energy of a photon depends on its wavelength. A photon is a particle of electromagnetic radiation. Matter cannot absorb or emit a fraction of a photon. A photon with a short wavelength is a form of high energy radiation.

Which of the following options correctly describe the different types of UV radiation? All these apply.

UVA is the least damaging to the Earth's surface. UVC radiation has the shortest wavelength. UV radiation with a wavelength of 300 NM is classified as UVB radiation.

Symbols and units for wavelength.

^ nm

Wavelength and frequency are ____ proportional to each other. As wavelength increases frequency will ____.

inversely; decrease

Select the correct symbol for frequency. m-1 € v ^

v

The distance a wave travels during one cycle is called it's ____. This is usually measured as the distance between two ____ or two troughs.

wavelength peaks (or crests)

Which of the following would correspond to types of radiation?

• X-rays from an X-ray machine at the hospital, • Visible light from a candle and • UV light from a black light are all types of radiation.