RBSE VU General Science key terms

Anything that has mass and occupies space. It exists in solid, liquid, and gas states, and can be classified as elements, compounds, or mixtures based on its composition.

A pure substance made of only one type of atom, which cannot be broken down into simpler substances by chemical means. Examples include oxygen, iron, and carbon.

A pure substance formed when two or more different elements are chemically bonded in fixed proportions. It has properties different from its constituent elements, such as water (H₂O).

A combination of two or more substances that are not chemically bonded and can be separated by physical means. Mixtures may be homogeneous (uniform) or heterogeneous (non-uniform).

The smallest particle of an element that retains the chemical properties of that element. It consists of a nucleus (protons and neutrons) surrounded by electrons.

The smallest particle of a covalent compound or element that can exist independently, consisting of two or more atoms chemically bonded together. For example, a water molecule (H₂O) has three atoms.

An atom or group of atoms that has gained or lost electrons, giving it a positive or negative electrical charge. Positive ions are cations; negative ions are anions.

The force that holds atoms together in a compound. Main types are ionic bonds (transfer of electrons) and covalent bonds (sharing of electrons).

A chemical bond formed by the electrostatic attraction between oppositely charged ions, typically between a metal and a non-metal. For example, sodium chloride (NaCl).

A chemical bond formed when two atoms share one or more pairs of electrons, usually between non-metals. For example, the bond in a hydrogen molecule (H₂).

A process in which one or more substances are changed into new substances with different properties. Reactants are converted into products, often with energy changes.

A starting substance in a chemical reaction that is consumed to form products. In the equation for burning methane, methane and oxygen are reactants.

A new substance formed as a result of a chemical reaction. In the reaction of hydrogen and oxygen to form water, water is the product.

A chemical equation in which the number of atoms of each element is the same on both sides, obeying the law of conservation of mass. Coefficients are used to balance it.

A substance that donates hydrogen ions (H⁺) in solution, has a pH less than 7, turns blue litmus red, and reacts with bases to form salts and water.

A substance that accepts hydrogen ions (H⁺) or releases hydroxide ions (OH⁻) in solution, has a pH greater than 7, turns red litmus blue, and neutralizes acids.

A scale from 0 to 14 measuring the acidity or alkalinity of a solution. A pH below 7 is acidic, 7 is neutral, and above 7 is basic.

An ionic compound formed when an acid reacts with a base in a neutralization reaction. For example, sodium chloride is formed from hydrochloric acid and sodium hydroxide.

An element that is typically shiny, malleable, ductile, and a good conductor of heat and electricity. Metals tend to lose electrons to form positive ions.

An element that generally lacks metallic properties, is a poor conductor of heat and electricity, and tends to gain or share electrons. Examples include oxygen, sulfur, and carbon.

A mixture of two or more metals, or a metal with a non-metal, to improve properties such as strength or resistance to corrosion. Steel is an alloy of iron and carbon.

A compound containing only carbon and hydrogen atoms, such as methane, propane, and ethene. Hydrocarbons are the main components of fossil fuels.

The basic structural and functional unit of all living organisms. Cells contain genetic material and carry out life processes such as respiration and reproduction.

The thin, flexible barrier that surrounds a cell and controls the movement of substances into and out of the cell. It is selectively permeable.

The process by which green plants and some other organisms use sunlight, carbon dioxide, and water to produce glucose and oxygen, using chlorophyll. It occurs in chloroplasts.

The process by which living cells break down glucose to release energy, often using oxygen and producing carbon dioxide and water. It occurs in all living organisms.

A group of similar cells that work together to perform a specific function. Examples include muscle tissue, nervous tissue, and epithelial tissue.

A structure made of different tissues working together to perform a particular function, such as the heart, lungs, or leaves of a plant.

A segment of DNA that contains the instructions for making a specific protein or trait. Genes are passed from parents to offspring and determine inherited characteristics.

Deoxyribonucleic acid, the molecule that carries genetic information in cells. It has a double-helix structure and consists of nucleotides with bases A, T, C, and G.

A thread-like structure of DNA and proteins found in the nucleus, carrying genes. Humans have 46 chromosomes (23 pairs) in most body cells.

The process by which individuals with traits better suited to their environment are more likely to survive and reproduce, passing those traits to offspring. It is a mechanism of evolution.

A diet that provides all the necessary nutrients in the correct proportions for good health, including carbohydrates, proteins, fats, vitamins, minerals, and water.

A health condition caused by a lack of a specific nutrient in the diet, such as scurvy from vitamin C deficiency or anaemia from iron deficiency.

A push or pull that can change an object's motion, direction, or shape. Force is measured in newtons (N) and has both magnitude and direction.

In physics, work is done when a force moves an object over a distance in the direction of the force. It is calculated as force multiplied by distance (W = F × d).

The capacity to do work or cause change. It exists in many forms, including kinetic, potential, thermal, chemical, and electrical energy, and is conserved in transformations.

A basic mechanical device that makes work easier by changing the magnitude or direction of a force. Examples include the lever, pulley, inclined plane, and wheel and axle.

The rate of flow of electric charge through a conductor, measured in amperes (A). It requires a closed circuit and a source of electromotive force.

A community of living organisms interacting with each other and with their non-living environment (such as air, water, and soil) in a particular area.