Test: Language of Chemistry - Class 8 MCQ

The molecular formula refers to a representation that shows the actual number of each type of atom in a molecule. For example, C₆H₁₂O₆ indicates that a glucose molecule contains six carbon atoms, twelve hydrogen atoms, and six oxygen atoms.

Balancing a chemical equation is significant because it ensures that the same number of atoms of each element is present on both sides of the equation, adhering to the law of conservation of mass.

Some elements have more than one valency because they can lose or gain different numbers of electrons when forming compounds. This property is essential in understanding how these elements react in various chemical contexts.

A radical refers to a group of different atoms that act as a single unit with a positive or negative charge. Radicals play a crucial role in many chemical reactions, especially in organic chemistry.

The symbol (s) indicates a solid state in a chemical equation. This notation helps convey the physical state of each reactant and product, which is important for understanding the nature of the reaction.

The first step in writing a chemical formula is to write the symbols of the elements or radicals in the compound. This sets the foundation for accurately representing the compound's composition.

An endothermic reaction is characterized by the absorption of heat. Such reactions require energy input, which is often indicated in chemical equations by the presence of "Heat" on the reactant side.

Symbols and formulas in chemistry serve the essential purpose of representing elements, compounds, and reactions in a concise and understandable manner. They allow chemists to communicate complex ideas and chemical interactions clearly and efficiently.

The balanced equation for methane burning in air is CH₄ + 2O₂ → CO₂ + 2H₂O. Balancing equations ensures that the number of each type of atom is the same on both sides, in accordance with the law of conservation of mass.

A cation is formed when an atom or group of atoms loses electrons, resulting in a positive charge. Understanding cations is fundamental in the study of ionic compounds and their properties.

Valency indicates the ability of an element to combine with other atoms, reflecting how many atoms can bond with it to form compounds. This property is crucial for predicting how elements interact in chemical reactions.

Sodium is represented by the symbol Na, derived from its Latin name "natrium." This illustrates how many element symbols come from languages other than English, highlighting the historical context of chemical nomenclature.

The abbreviation "aq" in a chemical equation signifies that a substance is in an aqueous solution, meaning it is dissolved in water. This notation is vital for understanding the conditions under which reactions occur, especially in solution chemistry.

An anion is formed when an atom or group of atoms gains electrons, resulting in a negative charge. This characteristic is fundamental in the formation of ionic compounds, where anions pair with cations.

A word equation shows the names of the substances involved in a chemical reaction. For example, "Hydrogen + Oxygen → Water" is a word equation, contrasting with a chemical equation that uses symbols and formulas.

A chemical formula is used to show which elements are present in a compound and the number of atoms of each element. For example, CO₂ indicates one carbon atom and two oxygen atoms in carbon dioxide.

A balanced chemical equation should include symbols representing the physical states of reactants and products, such as (s) for solids, (l) for liquids, (g) for gases, and (aq) for aqueous solutions. This information is essential for understanding the conditions of the reaction.

Hydrogen has a valency of 1, meaning it can combine with one atom of another element. This simple valency is fundamental in forming many compounds, such as water (H₂O), where hydrogen bonds with oxygen.

The primary goal of balancing a chemical equation is to ensure the conservation of mass, meaning the mass of the reactants equals the mass of the products. This principle is critical for accurately representing chemical reactions.

The law of conservation of mass states that in a chemical reaction, the total mass of the reactants must equal the total mass of the products. This principle is vital for balancing chemical equations and understanding chemical reactions.