Chemical Safety and Atmospheric Chemistry Lecture Notes

This set of vocabulary flashcards covers chemical laboratory safety protocols, historical case studies, and the composition and history of the Earth's atmosphere.

Flashpoint

The point at which a substance transitions from liquid to gas.

Anaerobic hood

An oxygen-free chamber used for working with bacteria that cannot survive in oxygen.

Hazard Communication

A system that allows workers to know the hazards and identities of chemicals they are exposed to, communicated through labels, Material Safety Data Sheets (MSDS), and education.

Material Safety Data Sheet (MSDS)

A document prepared by a chemical manufacturer describing physical and chemical properties, hazards, exposure routes, precautions, and emergency procedures.

Globally Harmonized System (GHS)

A 'non-binding' international system developed for classifying hazards and creating a standardized format for labels and safety data sheets (SDS).

Toxicity

The ability of a chemical to cause harm; referred to as "hazard" in general safety terms.

Risk

The likelihood of a material to cause harm under specific conditions of use.

Acute exposure

Short-term exposure to a substance that may cause immediate effects like eye irritation, nausea, dizziness, or burns.

Chronic exposure

Long-term exposure to a substance which can result in long-term illnesses.

Hierarchy of Risk Controls

A six-step priority list for safety: 1. Eliminate the hazard, 2. Substitute materials, 3. Engineering controls, 4. Awareness systems, 5. Administrative controls, 6. Personal protective equipment (PPE).

Personal Protective Equipment (PPE)

Items worn to minimize exposure to hazards, such as gloves, lab coats, eye protection, safety shoes, respirators, and face shields.

Dimethylmercury (DMM)

A highly toxic metal compound that can permeate latex gloves within $15\,\text{seconds}$.

Segregation

The use of physical barriers or distance in chemical storage to prevent incompatible materials from coming into contact.

Primitive Atmosphere

The atmosphere of Earth $4.5\,\text{Million}$ years ago, composed of Hydrogen, Helium, Ammonia, and Methane.

Secondary Atmosphere

An atmospheric stage caused by volcanic activity releasing gases like water vapor, carbon dioxide, and ammonia.

Oxidizing Atmosphere

An atmospheric stage where oxygen was produced through dissociation of water vapor, photosynthesis of cyanobacteria, and oxidation of metals.

Ozone ($O_3$)

A molecule formed when oxygen molecules absorb UV radiation; its formation made life on Earth possible.

Atmosphere

A thick mixture of gases surrounding the Earth's surface that acts as a shield and is held in place by gravity.

Karman Line

An imaginary line identifying the boundary between the Earth's atmosphere and outer space.

Residence Time

The average amount of time a gas spends in the atmosphere, calculated as the amount of the compound divided by its removal rate.

Nitrogen fixation

The process by which atmospheric $N_2$ is reduced to form ammonia, often by soil bacteria or lightning.

Denitrification

The reduction of nitrates to gaseous nitrogen by microorganisms through a series of biochemical reactions.

Argon

The third most abundant atmospheric gas, primarily composed of the radiogenic $^{40}Ar$ isotope derived from the decay of $^{40}K$ in the Earth's crust.

Saturation Level

The capacity of air to hold water vapor, which is dependent solely on air temperature.

Energy/Heat Budget

The description of the net flow of energy into Earth, mainly consisting of shortwave radiation and infrared longwave radiation.

Carbon Dioxide ($CO_2$)

An important greenhouse gas continually exchanged between the atmosphere and biosphere through photosynthesis and respiration.