This chapter introduces chemical reactions and equations, detailing how substances transform during reactions and the significance of balanced equations.
Chemical Reactions and Equations - Quick Look Revision Guide
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Key Points
Define chemical reaction with an example.
A chemical reaction involves the transformation of reactants into products through chemical changes. Example: Burning of magnesium ribbon in air to form magnesium oxide.
State the law of conservation of mass.
Mass can neither be created nor destroyed in a chemical reaction. The total mass of reactants equals the total mass of products.
Explain balanced chemical equations.
Balanced equations have equal numbers of each type of atom on both sides. Example: 2H2 + O2 → 2H2O.
Describe combination reaction.
Two or more substances combine to form a single product. Example: CaO + H2O → Ca(OH)2.
Explain decomposition reaction.
A single compound breaks down into two or more simpler substances. Example: 2FeSO4 → Fe2O3 + SO2 + SO3.
Define exothermic reaction.
Reactions that release heat energy. Example: Respiration releases energy used by cells.
Define endothermic reaction.
Reactions that absorb heat energy. Example: Decomposition of calcium carbonate requires heat.
Explain displacement reaction.
A more reactive element displaces a less reactive one from its compound. Example: Fe + CuSO4 → FeSO4 + Cu.
Describe double displacement reaction.
Exchange of ions between two reactants to form new compounds. Example: Na2SO4 + BaCl2 → BaSO4 + 2NaCl.
Define redox reaction.
Reactions involving oxidation and reduction. Example: CuO + H2 → Cu + H2O.
Explain oxidation.
Gain of oxygen or loss of hydrogen. Example: 2Cu + O2 → 2CuO.
Explain reduction.
Loss of oxygen or gain of hydrogen. Example: CuO + H2 → Cu + H2O.
Define corrosion.
Deterioration of metals due to reaction with environment. Example: Rusting of iron.
Explain rancidity.
Oxidation of fats/oils leading to bad smell/taste. Example: Spoilage of butter.
State the importance of balancing equations.
Ensures the law of conservation of mass is followed and provides correct stoichiometry.
Describe thermal decomposition.
Decomposition caused by heating. Example: 2Pb(NO3)2 → 2PbO + 4NO2 + O2.
Explain electrolysis of water.
Decomposition of water into hydrogen and oxygen using electricity. Example: 2H2O → 2H2 + O2.
Define precipitation reaction.
Formation of an insoluble solid (precipitate) during a reaction. Example: BaCl2 + Na2SO4 → BaSO4 + 2NaCl.
Explain the effect of light on silver chloride.
Silver chloride decomposes in sunlight to form silver and chlorine. Example: 2AgCl → 2Ag + Cl2.
Describe the reaction of zinc with sulphuric acid.
Zinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas. Example: Zn + H2SO4 → ZnSO4 + H2.
This chapter explores acids, bases, and salts, focusing on their properties, reactions, and everyday applications. Understanding these concepts is crucial for practical science and daily life.
This chapter focuses on the classification, properties, and reactivity of metals and non-metals.
This chapter explores the significance of carbon and its wide range of compounds. It highlights the unique properties of carbon that enable it to form various essential materials for life and industry.
This chapter discusses vital life processes that are essential for maintaining life in organisms. It explains the significance of these processes in ensuring survival and growth.
This chapter explains how living organisms control and coordinate their activities through nervous and hormonal systems. Understanding these processes is essential for grasping how organisms interact with their environments.
This chapter covers the various methods of reproduction in organisms and explains their significance for species survival and diversity.
Explore the fascinating world of heredity, understanding how traits are passed from parents to offspring through genes and chromosomes.
This chapter explains the concepts of light reflection and refraction, which are crucial for understanding how we see objects around us.
This chapter explores the structure and function of the human eye and explains optical phenomena like rainbows and the scattering of light.
This chapter introduces electricity, explaining its significance as a vital energy source in various applications. It covers the principles of electric current, circuits, and their regulation.
