CEM 142 Besocratic (Chp 5+6) Questions With Complete Solutions

CEM 142 Besocratic (Chp 5+6) Questions With Complete Solutions What happens to the number of distinguishable arrangements as the number of molecules in the system increase? Increase Once dye molecules are mixed up with the water molecules, they will not "unmix" why? The probability of the molecules in an "unmixed" state is much less compared to being in the "mixed" stat. The molecules have a higher positional entropy when mixed, as there are more possible ways the molecules can be arranged when they are mixed. As the number of molecules increase, the number of distinguishable arrangements increase. Suppose you have two copper blocks at different temperatures, what will happen when they come in contact? The hot block will transfer energy to the cold block, until both blocks are at the same temperature. Explain WHY energy transfers from a hot block to a cold block until they are both at the same temperature. Transferring energy from hotter to colder objects has more possible arrangements. Explain why we use Gibbs energy instead of considering the total entropy change when we are determine whether a process will occur? Gibbs energy express the changes that ONLY take place in the system, without the surroundings. It is easier to look at the system than the surroundings, because we are using criteria that only refers to the system. Also Gibbs's energy tells us how much energy is left to bring further change, since energy is always lost in the form of heat during phase change. What is the sign of delta H,S, and G when water freezes at -10c? H = - S = - G = - What is the sign of delta H,S, and G when water freezes at +10c? H = - S = - G= + What does the sign of delta G tells us about the system? The sign of delta G tells us whether a process will occur or not. If delta G is negative, then overall entropy is increasing. If delta is positive, then the overall entropy is decreasing and the process will not occur. oil is insoluble in water, why? non polar molecules cause water molecules to cluster around them. the water molecules become "fixed" in a cage like structure around the oil molecules. This decreases the entropy of the system and therefore the mixed state is thermodynamically unfavorable. Hence water and oil molecules remain