C/P Advice

For all of those reactions that the MCAT wants us to memorize, like Aldol Condensations, your time is best utilized being able to simply look at a reactant and pick out a product, or vice versa. You don’t particularly need to know the movement of all of the electrons at every single step, it’s vastly more important to understand the before and after. Memorize the highlights of a reaction!

All questions, such as, “which proton is the most acidic?” or, “where is the condensation most likely to occur?” all can be more easily answered if you have a good understanding of what makes a molecule stable. If you nail the foundations of resonance, the inductive effect, etc., it’ll be easier for you to see why those reactions happen in those locations, or why one molecule may be more reactive than another. In other words (and as an example), I’m saying to try to understand why carboxylic acids are more acidic than alcohols and other functional groups, not simply to memorize that fact.

In general, if something is going to have a really stable product after the reaction, that means it’s really likely to react. Check for the stability of the product, and the most stable product is the most reactive reactant!

There are a bunch of lab techniques that you’ll want to know for the MCAT, and it’s important that you understand the basic steps within each lab technique, and most importantly, be able to predict the results/interpret data. For example, you want to be able to understand a Western Blot, if they mention doing Mass Spectrometry you want to have a basic understanding of deflections and know what the results would be, etc.

I will have a cheat sheet for the lab techniques sometime in the future, sign up for updates to know when I’ve released it!

The MCAT loves to ask, “If we increase this, what happens to this?”, or, “If we double this, what happens to this?”. By getting practice understanding the relationships between variables with the equations, you’ll have a much easier time answering those questions.

For example, in the equation P = V²/R, you should be able to figure out that, if power is held constant (we are never told it changes), every time you double V, R would have to quadruple to keep the ratio the same. Or conversely, if R is held constant, every time we double V, P would quadruple. Being able to see relationships like this is instrumental to the C/P section of the MCAT.

Having a good understanding of the units of each variable in an equation used on the MCAT is going to help you out a ton with dimensional analysis and manipulating other equations they give you, as well as analyzing constants. I found it helpful to always try to cancel out units/include units in my math whenever I first started to practice physics and gen chem math, which made it much easier for me to understand the equations themselves, as well as where the equations came from.

As another example of how units are helpful for constants, the gas constant R = 0.082 atm*L/mol*K, L is a measurement of volume (V), atm is a measurement of pressure (P), K is a measure of temperature (T), and mol is just the number of moles (n). Notice that, if we substitute the units for the gas constant with the variable that the unit measures, L*atm/K*mol = PV/nT, which probably looks a lot like the PV = nRT equation (which, in fact, it is).

The units of a constant will cancel out with the other variables that are included in the equation, so in a way, the full equation is hidden within the units of the constant. If you understand this, it’ll make the equations and constants they give you on the MCAT easier to understand.

There’s a giant list of equations that you probably need to know (see my Equations Sheet), but you can make your life a bit easier by combining several equations into one.

For example, you’ll need to know that V = Ed, as well as F = qE, as well as W = Fd, so one and so forth. However, through the equation of Work, we can put all of these equations into one longer one that may be easier to memorize and then just pick and find which parts you need. W = Fd = qEd = qV, one long equation that shows you how V, E, F, d, and q are all linked to each other directly, and you can pick V = Ed out of that equation if you need to. It’s all there!

I also found this strategy to be helpful in connecting the many different equations with each other. It’s pretty hard at first to know where you’re supposed to go with the information they gave you, but after practice linking similar equations to each other like this, you’ll have a better grasp of where things are going.

This is only something I did at the start of my MCAT studying, but it really helped me to know how they like to connect a series of equations to each other.

For example, if they give you voltage, resistance, and an amount of time, looking to solve for Work. I would list out every equation I knew that included V or R (or t). For V, I know that V = IR, P = IV (which = V²/R = I²R), V = Ed, and several others, but by writing them out, I’m hoping that you can see that we can solve for power using the V and R that we were given through the question, and since Power is Work/time, we can use the time that they gave us to solve for Work.

Basically, if you’re stuck trying to use the equations, it may help to practice vomiting out every equation you know for a given variable to see if you can figure out how to link them all together. It takes time, but once those connections are made, they never go away!

You do not need to solve for exact numbers. On the MCAT, as long as you round properly, you will get close enough to the real answer that you shouldn’t need to worry about any more than 0 or 1 decimal places. Round 170 to 200, round 0.00426 to 0.004, etc., just make sure you keep track of which direction you rounded so you know whether you’re going to be higher or lower than the actual answer.

Everyone will approach the math slightly differently on the MCAT, but especially with nasty units like nanometers that are a super small decimal and hard to use when doing dimensional analysis, you may want to try converting all complex numbers to scientific notation to try out the math that way.

For example, let’s say you want to solve for the velocity of a wave, and the frequency is 1.8 kilohertz and the wavelength is 6.2 nanometers. We need to convert those to meters and Hertz, which would be .0000000062 meters and 1800 hertz, which we would be plugging into v = lambda*f. However, that’s not going to be super fun to do, so leave them in scientific notation and round: v = (6×10^-9 m)(2×10³ Hz). Multiply the two coefficients together: 6×2 = 12. Add the two exponents together (since we’re multiplying): (10^-9)(10³) = 10^-6. Put them together: 12×10^-6 m/s, and simplify: 1.2×10^-5 m/s is your answer (or roughly near it).

Find a math trick that works for you! I just always found scientific notation super helpful to do complex math by splitting it up like that.

This goes a bit into a discussion on “low vs high yield” stuff which I will discuss further in my General MCAT Advice section, but for now, I want to reiterate that those topics you don’t think a medical exam would ask about, such as nuclear decay, friction, polarization of light, etc., are entirely fair game. You don’t need to know a ton about most of those more complex topics within Physics, but you still need to know about them. You don’t need to be able to solve Heisenberg’s uncertainty equation, but you need to know what it’s for!