Question

Q1. Define and give one example of each:
a) Combination reaction
b) Thermal decomposition
c) Displacement reaction
d) Double displacement reaction
e) Exothermic reaction​

Answer 1

Answer:

a) Combination reaction

combination reaction (also known as a synthesis reaction[1]) is a reaction where two or more elements or compounds (reactants) combine to form a single compound (product). Such reactions are represented by equations of the following form: X + Y → XY.The combination of two or more elements to form one compound is called a combination reaction.

In other words, when two or more elements or compounds react so as to form one single compound, then the chemical reaction that takes place is called a combination reaction. | a)- Between elements | C + O2 → CO2 | Carbon completely burnt in oxygen yields carbon dioxide |- | b) Between compounds | CaO + H2O → Ca(OH)2 | Calcium oxide (lime) combined with water gives calcium hydroxide (slaked lime) |- | c) Between elements and compounds | 2CO + O2 → 2CO2 | Oxygen combines with carbon monoxide,And carbon dioxide is formed. |}

example is magnesium oxide combining with carbon dioxide to produce magnesium carbonate.

MgO + CO2 → MgCO3

b) Thermal decomposition

thermal decomposition reaction can be defined as a decomposition reaction which is activated by thermal energy. ... A common example of a thermal decomposition reaction is provided below. CaCO3 → CaO + CO2. When heated, calcium carbonate decomposes into calcium oxide and carbon dioxide.

calcium carbonate → calcium oxide + carbon dioxide

calcium carbonate → calcium oxide + carbon dioxideCaCO3 → CaO + CO2

Thermal decomposition is an example of an endothermic reaction, a reaction that gains energy from the surroundings.

c) Displacement reaction

Displacement reactions occur when a metal from the electrochemical series is mixed with the ions of a metal lower down in the electrochemical series. The atoms of the more reactive metal push their electrons on to ions of the less reactive metal.

example can be seen below.

CuSo4 + Zn➡️ Znsu4 + Cu

d)Double displacement reaction

double displacement reaction is a type of reaction in which two reactants exchange ions to form two new compounds. Double displacement reactions typically result in the formation of a product that is a precipitate.

Double displacement reactions take the form:

AB + CD → AD + CB

Double Displacement Reaction Examples

The reaction between silver nitrate and sodium chloride is a double displacement reaction. The silver trades its nitrite ion for the sodium's chloride ion, causing the sodium to pick up the nitrate anion.

AgNO3 + NaCl → AgCl + NaNO3

Here's another example:

BaCl2(aq) + Na2SO4(aq) → BaSO4(s) + 2 NaCl(aq)

e) Exothermic reaction

Exothermic Reaction

An Exothermic reaction is a chemical reaction that involves the release of energy in the form of heat or light. These reactions are the opposite of endothermic reactions and can be expressed in a chemical equation as follows: Reactants → Products + Energy

An exothermic reaction is a reaction in which energy is released in the form of light or heat. Thus in an exothermic reaction, energy is transferred into the surroundings rather than taking energy from the surroundings as in an endothermic reaction. In an exothermic reaction, change in enthalpy ( ΔH) will be negative.

An example of a combustion reaction would be the combustion of methane which can be represented as follows: CH4 + O2 → CO2 + H2O + Heat

Another example of a combustion reaction is the combustion of glucose, given by the following reaction: C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy