Chemical Reactions and Equations – Lecture Review

Vocabulary flashcards covering major terms and definitions from the lecture on chemical reactions and equations. 44 flashcards provided to encompass oxidation–reduction concepts, reaction types, safety practices, and factors influencing reaction rates.

Rusting

Slow oxidation of iron producing reddish-brown hydrated iron(III) oxide (Fe₂O₃·H₂O).

Galvanization

Applying a protective zinc layer on iron to prevent rusting by sacrificial protection.

Redox Reaction

A chemical reaction in which oxidation and reduction occur simultaneously.

Oxidation Reaction

Process in which a substance gains oxygen or loses hydrogen/electrons.

Reduction Reaction

Process in which a substance gains hydrogen or loses oxygen/electrons.

Electrolysis of Water

Decomposition of acidulated water into hydrogen and oxygen by passing electric current.

Double Displacement Reaction

Reaction in which ions of two compounds exchange partners, often forming a precipitate.

Displacement Reaction

Reaction where a more reactive element replaces a less reactive element in a compound.

Combination Reaction

Reaction in which two or more reactants combine to form a single product.

Decomposition Reaction

Reaction in which one reactant breaks down into two or more products.

Endothermic Reaction

Reaction that absorbs heat from its surroundings.

Exothermic Reaction

Reaction that releases heat to its surroundings.

Reactant

Substance that starts a chemical reaction and is consumed during the process.

Product

Substance formed as a result of a chemical reaction.

Balanced Chemical Equation

Equation containing equal numbers of each type of atom on both reactant and product sides.

Rate of Reaction

Speed at which reactants are converted into products per unit time.

Catalyst

Substance that increases the rate of a reaction without being consumed.

Manganese Dioxide (MnO₂)

Catalyst that speeds up the decomposition of hydrogen peroxide.

Ferrous Sulphate (FeSO₄)

Iron(II) compound that can be oxidized to ferric sulphate.

Ferric Sulphate (Fe₂(SO₄)₃)

Iron(III) compound obtained by oxidation of ferrous sulphate.

Limewater Test

Use of Ca(OH)₂ solution that turns milky in presence of CO₂ due to CaCO₃ formation.

Calcium Carbonate (CaCO₃)

Compound present in limestone; decomposes to CaO and CO₂ on heating.

Calcium Hydroxide (Ca(OH)₂)

Weak base formed when CaO reacts with water; constituent of limewater.

Rancidity

Spoilage of oils/fats due to air oxidation producing unpleasant odor and taste.

Antioxidant

Substance added to foodstuffs to prevent oxidative spoilage like rancidity.

Surface Area Effect

Increase in reaction rate when reactant is powdered, as in Shahabad tile vs. pieces.

Dilution of Sulphuric Acid

Exothermic process requiring slow addition of acid to water with stirring for safety.

Corrosion

Undesirable oxidation of metals by environmental agents causing damage.

Precipitate

Solid produced in a solution during a chemical reaction, e.g., BaCrO₄ in double displacement.

Barium Chromate (BaCrO₄)

Yellow precipitate formed from K₂CrO₄ and BaSO₄ reaction.

Silver Nitrate (AgNO₃)

Compound used in voter’s ink, mirrors, wound treatment, and electrical contacts.

Strong Alkali

Base that completely dissociates in water, e.g., aqueous NaOH.

Weak Alkali

Base that partially dissociates in water, e.g., aqueous Ca(OH)₂.

Factors Affecting Reaction Rate

Nature of reactants, particle size, concentration, temperature, and catalyst presence.

Nature of Reactants

Intrinsic chemical properties influencing how fast they react.

Concentration

Number of reactant particles per unit volume; higher concentration generally speeds reactions.

Temperature (Reaction)

Higher temperatures increase particle kinetic energy, raising reaction rate.

Anode (Rusting)

Region on iron surface where Fe is oxidized to Fe²⁺, releasing electrons.

Cathode (Rusting)

Region on iron surface where O₂ is reduced, often forming water.

Hydrogen Peroxide Decomposition

2H₂O₂ → 2H₂O + O₂; slow at room temp but accelerated by MnO₂ catalyst.

Stoichiometric Balancing

Adjusting coefficients to satisfy the law of conservation of mass in equations.

Air-Tight Storage

Keeping food or oils sealed from air to prevent oxidation and spoilage.

Sacrificial Protection

Prevention of corrosion by coating with a more reactive metal that oxidizes first (e.g., zinc).

Electrochemical Reaction

Chemical change involving electron transfer, such as rusting.