Which of the following phase changes is an exothermic change?
2 answers:
is an exothermic change.
Further Explanation:
Phase change:
The phase change is defined as the change from one state to another state without altering its chemical composition. It is also known as a phase transition, state change or physical change.
Phase changes are of two types:
1. Endothermic change: These changes take up energy from the surroundings, usually in the form of heat. For example, melting of ice is an endothermic phase change. It involves the change of solid state (ice) to the liquid state (water). Energy is to be supplied for this process and therefore it is an endothermic process.
2. Exothermic change: These changes release energy or heat to the surrounding environment. For example, freezing of water. It involves the conversion of liquid state (water) to the solid state (ice). Here, energy is released for this process and that’s why it is an exothermic process.
(A) Sublimation: It is the conversion of a substance directly from solid to vapor phase, without going through the liquid state. Naphthalene and dry ice are substances that undergo sublimation. The forces between the solid particles are very strong. In order to convert it into the gas phase, energy is to be supplied from the surrounding environment. So sublimation is an endothermic process.
(B) Deposition: It is the phase transition in which the vapors are directly converted into solid-state, without passing through the liquid intermediate. It is just the reverse of sublimation and is therefore known as desublimation. The gas particles have a high degree of randomness and the least intermolecular forces in them. So its particles move in all directions with high speed. In order to convert them into the solid-state, their motion needs to slow down and for this, energy is released. So deposition is an exothermic process.
(C) Vaporization: It is the phase transition that converts the liquid into vapors. In order to change the liquid state to the vapor state, the temperature is to be increased or heating is done. Heat is supplied to the system from the surrounding environment. So vaporization is an endothermic process.
(D) Melting: It is the phase transition that results in the conversion of solid-state to the liquid state. Since the solid particles have stronger intermolecular forces between them as compared to that in liquids. In order to overcome such strong forces, energy is supplied in the form of heat and therefore melting is an endothermic process.
Learn more:
1. Identify the phase change in which crystal lattice is formed: brainly.com/question/1503216
2. The main purpose of conducting experiments: brainly.com/question/5096428
Answer details:
Grade: Senior School
Subject: Chemistry
Chapter: Phase transition
Keywords: exothermic, endothermic, sublimation, deposition, vaporization, melting, phase transition, phase change, state change, physical change, solid state, liquid state, vapor state.
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