Test: Substance and it's Nature - SSC CGL MCQ

Plasma is a high-energy state of matter where atoms are ionized, meaning electrons are separated from nuclei. This state is commonly found in stars like the sun and certain laboratory conditions. An interesting fact about plasma is that it is often referred to as the fourth state of matter, distinct from solids, liquids, and gases due to its unique properties.

A Bose-Einstein Condensate (BEC) is a state of matter that forms at temperatures close to absolute zero. In this state, particles occupy the same space and quantum state, essentially acting as a single quantum entity. This phenomenon was first predicted by Satyendra Nath Bose and Albert Einstein in the early 1920s. BECs exhibit unique quantum effects on a macroscopic scale, making them fascinating subjects of study in physics.

Liquids are characterized by particles that are closely packed but not in a fixed arrangement. They have a definite volume but take the shape of their container. This property allows liquids to flow and adapt to the shape of their surroundings. An interesting fact about liquids is that they exhibit surface tension, a phenomenon that gives rise to unique behaviors such as capillary action and droplet formation.

Density is the property of matter that is defined as the mass per unit volume of a substance. It is calculated using the formula Density (ρ) = Mass (m) / Volume (V). An interesting fact is that density is a key characteristic used to identify and classify materials in various fields such as physics, chemistry, and engineering.

Conductivity is the property of matter that describes its ability to conduct electricity or heat. Materials can be classified based on their conductivity properties, with metals typically being good conductors of electricity and heat. This property is crucial in various applications ranging from electrical wiring to thermal management in industrial processes.

The characteristic of matter that refers to the temperature at which a solid transforms into a liquid is known as the melting point. It is an essential property used to identify substances and understand their behavior under different conditions. Interestingly, the melting point can vary widely among different materials, influencing their physical states and applications in various industries.

Democritus is credited with proposing that matter is composed of indivisible particles called "atomos." This concept of atoms as the fundamental building blocks of matter laid the foundation for modern atomic theory.

Ernest Rutherford is known for conducting the gold foil experiment, which led to the proposal of the nuclear model of the atom. This model suggested that atoms have a dense, positively charged nucleus surrounded by electrons.

Compounds are formed when two or more elements chemically combine in a fixed ratio, resulting in a substance with properties different from the elements that form it. Unlike elements, compounds can be broken down into simpler substances through chemical means.

The primary component of atoms that accounts for most of the atom's mass is the nucleus, which contains protons and neutrons. The nucleus is surrounded by electrons in various energy levels or orbitals. Neutrons and protons are located within the nucleus, while electrons orbit around it in shells.

Covalent bonds are formed by the sharing of electrons between atoms. This sharing of electrons allows each atom to achieve a more stable electron configuration. Covalent bonds are commonly found in molecules such as H2, O2, and H2O.

Henry Moseley arranged elements in the periodic table by atomic number, which led to the modern periodic table organization we use today. By organizing elements by atomic number, Moseley's work provided a more accurate way to categorize elements and understand their properties based on the number of protons in their nuclei.

Combination reactions involve two or more substances combining to form a single product. In this type of reaction, two or more reactants come together to form a single product. An example of a combination reaction is the formation of water from hydrogen and oxygen gases.

Balancing chemical equations is essential to ensure the conservation of mass. This process involves making sure that the number of atoms of each element is the same on both sides of the equation. By balancing chemical equations, we maintain the fundamental principle of conservation of mass, which states that matter is neither created nor destroyed in a chemical reaction.

The mole concept in stoichiometry is based on Avogadro's number, which is 6.022 × 10^23 particles in one mole of a substance. This concept allows chemists to relate the mass of a substance to the number of particles it contains, facilitating calculations in chemical reactions.