Endothermic Reactions Explained
An endothermic reaction is a type of chemical reaction that absorbs energy, usually in the form of heat, from its surroundings. This absorption of energy causes the temperature of the surroundings to decrease. In contrast, exothermic reactions release energy into the surroundings.
We need to identify which of the given reactions is endothermic. Let's analyze each option:
Reaction Analysis: Option 1 - Methane Combustion
The reaction provided is:
This reaction appears to represent the combustion of methane (\(CH_4\)). Although the products listed (\(CO_2 (g) + 2O_2 (g)\)) seem unconventional (typically it should be \(CO_2 (g) + 2H_2O (g)\)), combustion reactions, where a substance reacts rapidly with oxygen, are almost always exothermic. They release significant amounts of energy as heat and light.
Reaction Analysis: Option 2 - Glucose Respiration
The reaction provided is:
This equation represents the aerobic respiration of glucose (\(C_6H_{12}O_6\)). This biological process breaks down glucose in the presence of oxygen to produce carbon dioxide and water. Respiration is a fundamental metabolic process that releases energy for living organisms and is highly exothermic.
Reaction Analysis: Option 3 - Ammonia Synthesis
The reaction provided is:
This is the Haber-Bosch process for the synthesis of ammonia (\(NH_3\)) from nitrogen (\(N_2\)) and hydrogen (\(H_2\)). This reaction is known to be exothermic, releasing heat when ammonia is formed.
Reaction Analysis: Option 4 - Lead Nitrate Decomposition
The reaction provided is:
This reaction describes the thermal decomposition of solid lead(II) nitrate (\(Pb(NO_3)_2\)) into solid lead(II) oxide (PbO), nitrogen dioxide gas (\(NO_2\)), and oxygen gas (\(O_2\)). Decomposition reactions, especially those involving the breakdown of nitrates upon heating, typically require energy input (heat) to occur. Therefore, this is an endothermic process, as it absorbs heat from the surroundings.
| Reaction Option | Description | Energy Change |
|---|---|---|
| 1 | Methane Combustion (Assumed) | Exothermic |
| 2 | Glucose Respiration | Exothermic |
| 3 | Ammonia Synthesis (Haber Process) | Exothermic |
| 4 | Lead Nitrate Decomposition | Endothermic |
Based on the analysis, the decomposition of lead(II) nitrate is the endothermic reaction among the choices.
Similar Questions
- The chemical reaction:
\(2AgCl (s) \to 2Ag (s) + Cl_2 (g)\)
takes place Which one among the following is an example of oxidation reaction?
Which one among the following is an example of chemical change?
- Which one of the following is NOT a chemical change?
- The reaction that occurs on passing carbon dioxide gas through lime water is
Match List I with List II and select the answer using the code given below the Lists:
List I
(Reaction)List II
(Type)A. \(CaO (s) + H_2O (l) \rightarrow Ca(OH)_2 (aq)\) 1. Single displacement B. \(CaCO_3 (s) \rightarrow CaO (s) + CO_2 (g)\) 2. Double displacement C. \(Pb (s) + CuCl_2 (aq) \rightarrow PbCl_2 (aq) + Cu (s)\) 3. Combination D. \(Na_2SO_4 (aq) + BaCl_2 (aq) \rightarrow BaSO_4 (s) + 2NaCl (aq)\) 4. Decomposition
Code:
Important Questions from Chemical Reactions
Which of the following is/are the example/examples of chemical change?
(1) Crystallization of sodium chloride
(2) Melting of ice
(3) Souring of milk
Select the correct answer using the code given below.
Aspartame is an artificial sweetener sold in the market. It consists of amino acids and provides calories like other amino acids. Yet, it is used as a low-calorie sweetening agent in food items. What is the basis of this use?
Photochemical smog is a resultant of the reaction among
- Phosphorus is kept in water because
What is the product formed when sodium bicarbonate is heated strongly?
