Chemical Reactions and Equations

Comprehensive vocabulary flashcards covering the core concepts, laboratory activities, reaction classifications, chemical equations, and everyday oxidation effects from Chapter 1: Chemical Reactions and Equations.

Chemical Reaction

A process in which the nature and identity of the initial substance change through the breaking and making of bonds between atoms to produce new substances.

Reactants

The substances that undergo chemical change in a chemical reaction, written on the left-hand side (LHS) of a chemical equation.

Products

The new substances formed during a chemical reaction, written on the right-hand side (RHS) of a chemical equation.

Word-Equation

A representation of a chemical reaction using the names of reactants and products, linked by an arrow pointing toward the products to indicate the reaction direction.

Skeletal Chemical Equation

An unbalanced chemical equation written with chemical formulae where the number of atoms of each element is not equal on both sides of the arrow.

Balanced Chemical Equation

A chemical equation in which the total mass and the number of atoms of each element are identical on both the reactant and product sides.

Law of Conservation of Mass

The principle stating that mass can neither be created nor destroyed in a chemical reaction, requiring total reactant mass to equal total product mass.

Hit-and-Trial Method

A method of balancing chemical equations by making successive trials to balance atoms on each side using the smallest whole-number coefficients.

Aqueous $(aq)$

The physical state notation indicating that a reactant or product is dissolved as a solution in water.

Combination Reaction

A chemical reaction in which two or more substances (elements or compounds) combine to form a single product.

Quick Lime

The common name for calcium oxide ($\text{CaO}$), which reacts vigorously with water to form slaked lime and releases a large amount of heat.

Slaked Lime

The common name for calcium hydroxide ($\text{Ca(OH)}_2$), formed when quick lime reacts with water.

Exothermic Chemical Reaction

A reaction in which heat is released along with the formation of products, making the reaction mixture warm.

Decomposition Reaction

A chemical reaction in which a single reactant breaks down to yield two or more simpler products.

Thermal Decomposition

A decomposition reaction that is driven by the application of heat to break down the reactant.

Endothermic Reaction

A chemical reaction in which energy is absorbed from the surroundings in the form of heat, light, or electricity.

Displacement Reaction

A reaction in which a more reactive element displaces or removes another element from its compound.

Precipitate

An insoluble solid substance that separates out from a solution during a chemical reaction.

Precipitation Reaction

Any chemical reaction that produces an insoluble precipitate.

Double Displacement Reaction

A reaction in which there is a mutual exchange of ions between two reacting compounds to form two new compounds.

Oxidation

A chemical process characterized by the gain of oxygen or the loss of hydrogen by a substance.

Reduction

A chemical process characterized by the loss of oxygen or the gain of hydrogen by a substance.

Redox Reaction

A reaction in which oxidation and reduction occur simultaneously, with one reactant being oxidised while the other is reduced.

Corrosion

The gradual deterioration of a metal when it is attacked by substances around it, such as moisture and acids.

Rusting

The specific corrosion process in which iron articles get coated with a reddish-brown powder when left exposed to a humid atmosphere.

Rancidity

The spoilage of fat- and oil-containing food items caused by oxidation, leading to an unpleasant alteration in taste and smell.

Antioxidants

Substances added to foods containing fats and oils to prevent oxidation and retard rancidity.

Chemical Reaction

A process in which initial substances undergo a chemical change involving the breaking and making of bonds between atoms to produce new substances with altered chemical identities and properties.

Reactants

The starting substances that undergo chemical transformation during a reaction, written on the left-hand side (LHS) of a chemical equation.

Products

The new substances formed as a result of a chemical reaction, written on the right-hand side (RHS) of a chemical equation.

Burning of Magnesium Ribbon

The combustion of a cleaned magnesium ribbon in air with a dazzling white flame to form a white powder of magnesium oxide ($2Mg + O_2 \rightarrow 2MgO$).

Evolution of Hydrogen Gas from Zinc

The chemical reaction occurring when dilute sulphuric acid or hydrochloric acid is added to zinc granules ($Zn + H_2SO_4 \rightarrow ZnSO_4 + H_2$), producing gas bubbles and an increase in temperature.

Skeletal Chemical Equation

An unbalanced chemical equation that represents a reaction using the chemical formulae of reactants and products, where the number of atoms of each element is not equal on both sides.

Balanced Chemical Equation

A chemical equation in which the total mass and the number of atoms of each element remain identical on both the reactant and product sides, satisfying the law of conservation of mass.

Hit-and-Trial Method

A systematic method of balancing chemical equations by testing smallest whole-number coefficients to equalize the number of atoms of each element on both sides of the arrow.

Aqueous State $(aq)$

A physical state notation added to a chemical formula in an equation to indicate that the reactant or product is present as a solution in water.

Combination Reaction

A type of chemical reaction where two or more substances (elements or compounds) combine to yield a single product.

Quick Lime

The common commercial name for solid calcium oxide ($CaO$), which reacts vigorously with water releasing large amounts of heat to form slaked lime.

Slaked Lime

The common name for calcium hydroxide ($Ca(OH)_2$), prepared by reacting quick lime ($CaO$) with water; used for whitewashing walls where it slowly reacts with atmospheric $CO_2$ to produce a shiny layer of $CaCO_3$.

Exothermic Chemical Reaction

A reaction in which energy or heat is evolved alongside the formation of products, such as in respiration, combustion of natural gas, and decomposition of vegetable matter.

Endothermic Reaction

A reaction in which energy is absorbed from the surroundings in the form of heat, light, or electricity to decompose or transform reactants.

Decomposition Reaction

A type of chemical reaction in which a single reactant breaks down into two or more simpler products.

Thermal Decomposition

A decomposition reaction that is driven by the absorption of heat energy, such as heating limestone ($CaCO_3$) to produce calcium oxide ($CaO$) and carbon dioxide ($CO_2$).

Thermal Decomposition of Ferrous Sulphate

A reaction where green ferrous sulphate crystals ($FeSO_4 \cdot 7H_2O$) lose water and decompose upon heating into solid ferric oxide ($Fe_2O_3$) and gases sulphur dioxide ($SO_2$) and sulphur trioxide ($SO_3$).

Electrolysis of Water

The electrochemical decomposition of acidified water into hydrogen gas at the cathode and oxygen gas at the anode in a $2:1$ volumetric ratio.

Photochemical Decomposition of Silver Chloride

The light-activated decomposition where white silver chloride ($AgCl$) turns grey when exposed to sunlight, separating into silver metal ($Ag$) and chlorine gas ($Cl_2$).

Displacement Reaction

A chemical reaction in which a more reactive element displaces a less reactive element from its aqueous salt solution, such as iron displacing copper from copper sulphate solution.

Double Displacement Reaction

A chemical reaction that involves a mutual exchange of ions between two reactant compounds to produce two entirely new compounds.

Precipitate

An insoluble solid substance that separates out from a liquid solution during a chemical reaction.

Precipitation Reaction

Any chemical process occurring between aqueous solutions that produces an insoluble salt or precipitate.

Oxidation

A chemical process characterized by the gain of oxygen or the loss of hydrogen by a substance during a reaction.

Reduction

A chemical process characterized by the loss of oxygen or the gain of hydrogen by a substance during a reaction.

Redox Reaction

An oxidation-reduction reaction where one reactant undergoes oxidation while the other undergoes reduction simultaneously.

Corrosion

The slow degradation of a metal surface caused by chemical attack from environmental agents such as moisture, oxygen, and acids.

Rusting of Iron

A form of metallic corrosion where iron articles develop a reddish-brown powdery layer upon prolonged exposure to moist air.

Rancidity

The aerial oxidation of fats and oils contained in foods over time, leading to an unpleasant alteration in taste and odor.

Antioxidants

Substances added to foods containing fats and oils that retard or prevent oxidation, thereby preventing rancidity.