Chemistry and Biology Review: Non-Metals, Air Pollution, Cell Division, and Soil

Flashcards covering key vocabulary from Chapter 13 (Non-metals), Chapter 15 (Soil), and Chapter 16 (Cell Division).

Graphite

A form of carbon that is black, soft, and slippery; it is the only non-metal that can conduct electricity and is used for electrodes, pencils, and lubricants.

Diamond

A shiny and hard natural mineral made of carbon; used in industry for drills and cutting tools, and as expensive ornaments due to its rarity.

Amorphous carbon

Carbon forms like charcoal, carbon black, and coal that do not have a definite crystalline structure.

Allotropes

Different structural forms of the same element; for example, graphite and diamond are allotropes of carbon.

Sulphur ($S$)

A pale yellow solid found in volcanic areas; it exists in rhombic, monoclinic, and plastic forms, and is insoluble in water but dissolves in carbon disulphide.

Sulphur dioxide ($SO_2$)

A toxic gas with an irritating smell produced when sulphur burns in air; it is a major cause of acid rain and can cause bronchitis and pneumonia.

Sulphuric acid ($H_2SO_4$)

Known as the "Mother of chemical industry," this substance is used in the production of fertilizers, plastics, dyes, and explosives.

Phosphine

A gas produced by decaying dead bodies that burns spontaneously in air to produce a blue "ghostly flame" seen in cemeteries at night.

White phosphorus

A pale yellow, waxy solid that must be kept in water because it burns spontaneously in air; used for smoke bombs.

Red phosphorus

A dark red powder used on the sides of matchboxes; it is not toxic and does not burn spontaneously in air.

Carbon monoxide ($CO$)

A gas produced by the incomplete combustion of fuels; it deprives the body of $O_2$, causing headaches, fatigue, and impaired vision.

Photochemical smog

A mixture of pollutants formed when nitrogen oxides and hydrocarbons react with ultraviolet rays; it results in oxidants like ozone ($O_3$) and PAN.

Acid rain

Precipitation with a pH less than $5.6$; formed when sulphur dioxides and nitrogen oxides combine with water vapor in the atmosphere.

Greenhouse effect

A natural process where gases like $CO_2$ trap infrared radiation (heat) to keep the Earth warm enough to sustain life.

Ozone layer

A region in the lower portion of the stratosphere that absorbs a large amount of ultra-violet (UV) rays from the sun.

CFCs (Chlorofluorocarbons)

Substances used in refrigerators and plastic foam that contribute to the depletion of the ozone layer.

Mitosis

Somatic (body) cell division that increases the number of cells for growth and development; produces two daughter cells with the same number of chromosomes as the parent cell (diploid).

Meiosis

Cell division occurring in reproductive cells to form haploid gametes (sperm or egg); involves two successive divisions to produce four daughter cells.

Chromatid

One of the two identical halves of a self-duplicated chromosome that are joined at the centromere.

Root cap

The structure at the very end of the root tip that protects the growth pyramid as the root grows through soil.

Meristem zone

The region at the very tip of the shoot or root where active cell division occurs.

Weathering

The process by which rock is broken down into small fragments over long periods by physical, chemical, or biological agents.

Humus

Decaying organic matter from dead plants and animals that increases soil fertility and water-holding ability.

Clay soil

Soil with very small mineral particles ($< 0.002 \text{ mm}$) characterized by poor drainage but high water retention due to capillary pull.

Loamy soil

Also known as garden soil; it contains a balance of silt, clay, sand, and humus, making it ideal for plant growth.

Peat soil

A dark brown, acidic soil high in organic matter ($50{\%}$) but low in cultivation value unless treated with quicklime (calcium oxide).