Reason: Gases are more disordered than solids. Ii) 1 mole of NaCl(s) or 1 mole of HCl(g) at 25 oC Reason: Although both diamond and graphite are solids and have a giant molecular structure, graphite has a less ordered structure. Which of the following substance has a greater entropy in each pair and explain your choice. GCE A-Level H2 Chemistry Exam-Based Questions on Entropy: This is because H 2 molecules are free to move in a larger volume and the system becomes less orderly. randomness) of the system increases when the pressure decreases from 3 atm to 1 atm. system becomes more ordered, less random.Įntropy (i.e. randomness) of the system decreases because the crystalline structure of NaCl(s) formed is highly ordered and very regular i.e. randomness) of the system increases because when temperature is increased, water molecules can now move more freely in the liquid and orderliness is reduced.Įntropy (i.e. system becomes more random, less orderly.ī) Liquid Water at 25 oC –> Liquid Water at 30 oCĮntropy (i.e. randomness) of the system increases because as ice melts to form liquid water, the regular crystalline structure of ice is broken and water molecules move freely in the liquid state i.e. To predict whether the entropy is increasing or decreasing in a particular system, let’s look into a few examples below:Įntropy (i.e. Next, we are going to look at the application side of how entropy is commonly discussed in everyday Chemistry. I am sure you learned something useful today regarding how changes in temperature, phase, number of moles of particles and mixing can cause changes in the entropy of a system. When you mixed 2 gases together, diffusion will occur randomly between the gases and their orderliness is reduced i.e. When you dissolve a solute into a solvent to form a solution (a mixture), the entropy increases since the solute particles are now randomly arranged in between the solvent particles. Mixing always leads to increase in disorderliness i.e. 3) Change in Number of Particles (especially for Gases)Īs the number of moles of particles in a system increases, it causes more disorderliness and thus entropy increases. 2) Change in TemperatureĪs temperature increases, the entropy of a system also increases.Īs temperature increases, the particles undergo greater vibration (in solids) and more rapid movement (in liquids and gases). They are not constrained to be close to each other. The entropy of a gas is much greater than that of a liquid because gaseous particles are very far apart from each other and can move freely at great speeds. Thus, it’s structure is highly ordered.Ī liquid has higher entropy than solid because its particles are arranged in an irregular pattern, although the particles are still quite close together. 4 Factors that affects the Entropy of a chemical system: 1) Change in Phase (Physical State)Ī solid has the lowest entropy because their particles are closely packed together and held in regular pattern. The more “mixed up” or “disorderly” or “messy” a system becomes, we say the entropy of the system increases. Entropy, S, is defined as the measure of the disorder or randomness in a system.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |