9.27 A

[Michelle Dong 1F]

Which substance in each of the following pairs has the higher molar entropy at 298 K?
(a) HBr (g) or HF(g)

Can someone explain why HBr (g) has higher molar entropy? How can you tell if something has higher molar entropy in general? Is there a trend?

[Mitch Mologne 1A]

The more particles the molecule has, the higher the molar entropy. Because HBr is a bigger molecule (thus more particles) it will have the higher molar entropy.

[SitharaMenon2B]

The trend is that the more complex a molecule is, the higher the molar entropy is. This is because a more complex molecule with more atoms can be arranged in a lot more configurations.

[Felicia Fong 2G]

Bromine is farther down the periodic table than Flourine. Thus, Bromine is larger and contains more elementary particles than F in HF. More particles means more entropy. To compare entropies, look at the states of matter if they are different. Entropy increases from solid to liquid to gas.

[Sarah Clemens 1B]

Since Br is a bigger molecule than F it makes it more complex which means it also has a larger entropy.

[Jana Sun 1I]

Bromine is farther down the periodic table than Flourine. Thus, Bromine is larger and contains more elementary particles than F in HF. More particles means more entropy. To compare entropies, look at the states of matter if they are different. Entropy increases from solid to liquid to gas.

What exactly are the "elementary particles" you mention?