Tag Archives: Physical Chemistry

How many types of ice are there?

When we think of water, we usually think of it having three states: solid, liquid, and gaseous. Water is a liquid between 0°C and 100°C (32°F and 212°F) under our standard atmospheric pressure of 1 atmosphere (760 Torr, 14.7 psi, 1.013 bar). Above 100°C, water becomes a gas (vapour), and below 0°C, water becomes a solid (ice). The pressure also affects the temperature at which the phase change occurs: in a pressure cooker, the temperature can reach 121°C with an additional 1 bar of pressure (0.987 atm, 750 Torr, 14.5 psi) before boiling. In a freeze dryer, the vacuum reduces the pressure as low as 0.1 mbar (9.87 x 10^-5 atm, 75 mTorr, 0.00145 psi), where water can boil at almost -40°C. This information can be displayed in a graph called a phase diagram, displaying the phase of the substance at a given pressure and temperature.

Phase diagram of water. Credit: Wikimedia

However, there are multiple possible crystal structures the water molecules can arrange themselves into, with different forms being favoured at different temperatures and pressures, and with different stabilities and ordering. This can be shown in a more complex phase diagram.

Phase diagram of water, with multiple phases of ice included. Credit: Wikimedia

Most of the ice on earth is in the ice I phase, specifically ice Ih, which is the hexagonal form of ice that we encounter in everyday life. As of 2021, there are now twenty known crystalline forms of ice (Hansen, 2021) with scientists still attempting to discover more. This results in a very complicated phase diagram of different phases of ice (Fig 1 in link).

In addition to crystalline ice, there is also amorphous ice. Amorphous solids do not have a defined crystal structure – one example in daily life is glass. Hence, amorphous ice is often described as being “glassy” or “vitreous”. So far, three forms of amorphous ice have been identified (Martoňáka et al., 2005). All these forms of ice have distinct properties, as well.

Even though water may seem simple, there is still plenty of ongoing research on the peculiarities of water and its properties. Scientists speculate that there may be further forms of ice that have yet to be discovered… perhaps you will join the search?

CHEM 205: Physical Chemistry

A potentially fun course ruined by poor administration and lack of communication. CHEM 205 focuses on the fundamentals of thermodynamics, kinetics, and spectroscopy useful for life science students.

format of the course

Lectures consisted of a professor going through a slide deck, as well as in-class practice problems. Conceptually the material was quite interesting, however the derivations for different equations can be quite dry to listen to. There were homework questions which weren’t incredibly challenging, but doing the math can become quite tedious.

gpa 🙂 or 🙁

This is a GPA booster if you’re good at math, otherwise it’s pretty GPA neutral. Personally, I found the evaluations to be ridiculously unfair. For the final exam, it was an EXACT (WORD FOR WORD) copy of a past 2013 final exam. Although this final exam was not released formally, the solutions could be found on CourseHero. Basically, if you had access to this exam beforehand you were getting an A+.

What’s more off-putting is that several individuals on Piazza actually defended viewing the exam beforehand. Their reasoning being that everyone who didn’t have access were all idiots for not taking advantage of all their resources (we now know in these COVID times – Chegg and coursehero is tantamount to academic dishonesty).

Unfortunately, even before the final exam – these same individuals were stirring trouble within the class. After a particularly difficult midterm, they were taunting others telling them that “you wont make medical school if you didn’t get 100 on this midterm” – really living up to the toxic premed stereotype (funny thing being that noone brought up the subject of medical school either … how they correlated performance in a physical chemistry course to medical school admissions is beyond me).

CHEM 205 grade distribution. Credits: ubcgrades.com

verdict? to take or not to take

Considering my toxic experience with my course I cannot recommend this to anyone. In fact, I don’t think things have gotten any better.