Answer:
Combination reactions, also known as synthesis reactions, involve the combination of two or more reactants to form a single product. These reactions often involve the formation of chemical bonds between the reactants, and they are usually exothermic, meaning that they release energy in the form of heat. Examples of combination reactions include the formation of water from hydrogen and oxygen, the synthesis of ammonia from nitrogen and hydrogen, and the combination of sodium and chlorine to form sodium chloride.
Decomposition reactions involve the breakdown of a single compound into two or more simpler substances. These reactions often involve the breaking of chemical bonds, and they are usually endothermic, meaning that they absorb energy from their surroundings. Examples of decomposition reactions include the breakdown of water into hydrogen and oxygen by electrolysis, the decomposition of hydrogen peroxide into water and oxygen, and the thermal decomposition of calcium carbonate into calcium oxide and carbon dioxide.
Replacement reactions, also known as substitution reactions, involve the replacement of one element or group of atoms in a compound by another element or group. These reactions often involve the transfer of electrons between reactants, and they can be either exothermic or endothermic depending on the specific reaction. Examples of replacement reactions include the displacement of hydrogen by a metal in a metal-acid reaction, the substitution of chlorine for hydrogen in an alkyl halide, and the replacement of a metal ion by another metal ion in a precipitation reaction.
Overall, combination reactions involve the combination of two or more reactants to form a single product, decomposition reactions involve the breakdown