Molecular systems tend to move spontaneously to a state of maximum randomness or disorder. Molecular randomness, or disorder, is called entropy and is denoted by the symbol S. As a state function, entropy change, ΔS, depends only on initial and final states. ΔS has a positive value when disorder increases and a negative value when disorder decreases. The following conditions usually result in an increase in entropy: a change of phase: solid→liquid→gas, an increase in the number of gas molecules, or a solid dissolving to form a solution. Although the sign of the entropy change can be predicted as described above, the actual value of ΔS∘ must be calculated from the absolute entropy values, S∘, of the reactants and products: ΔS∘=S∘(products)−S∘(reactants).

Electromagnets coils of wire paper clips picked up 10 3 15 6 20 9 25 12 ms. owens' class was studying magnets. ms. owens showed her students how to make an electromagnet using a nail, a d-cell battery, and plastic coated wire. the students wrapped the wire around the nail and then attached the ends to the battery. when they were finished, they tested their magnets by investigating how many paperclips their magnets could pick up. they also tested whether they could increase the strength of their electromagnets by using more coils of wire. they recorded the class average of their results in the data table seen here. ms. owens asked her students to graph their data in a line graph. how should the students label the x-axis on their line graph? a) size of battery b) number of paper clips c) number of coils of wire d) strength of electromagnet