Collegechemistry

We found 24 articles

Chromatography: purifying your understanding
Maybe you were studying for the MCAT or just in your college chemistry lab when it dawned on you: why are there so many different types of chromatography? What do they have in common and what are their differences? 
How to solve an empirical formula problem
In this blog post, we will review how to determine the empirical formula of a compound using the mass percentages of the elements from which it is formed.
Quantum numbers
In this blog post, we explore the four quantum numbers, which allow us to describe the properties of each electron within an atom. According to the Pauli Exclusion Principle, no two electrons can share the same combination of quantum numbers. A carbon atom has six electrons, for example, and each of these electrons can be described by one of six ...
A painless introduction to VSEPR theory
Today we will discuss VSEPR (pronounced “vesper”), which stands for valence-shell electron-pair repulsion. The basis of VSEPR is that the electrons in bonds and lone pairs repel each other. To minimize the instability that results from these repulsions, a molecule will adopt the shape that places electron groups as far apart as possible. VSEPR ...
Tips for success in organic chemistry courses
Organic chemistry is historically considered a “weed-out” class for pre-medical students and often the cause of much frustration for students. After spending 3 years during college serving as a teaching assistant and tutor for organic chemistry courses at my undergraduate university, here are some tips for studying for your organic chemistry ...
Drawing the chair conformation of a pyranose ring
In this blog post, we will complete the following example problem:
How to balance redox reactions in acidic and basic solutions
Balancing redox reactions is an essential skill for the Chemical and Physical Foundations section of the MCAT, the GRE Chemistry Subject Test, and the AP Chemistry Exam. Today, we will learn how to use the half-cell method for balancing redox reactions in acidic and basic solutions. We will first balance a redox reaction in acidic solution, then ...
Using pKa to predict protonation state
When you've learned about pKa, you've most likely used it in acid-base calculations. However, some exams may ask you to apply a conceptual knowledge of pKa to predict whether a chemical compound is charged or uncharged.
S’more fun: simplifying limiting reactants using chocolate
Stoichiometry: it’s the bane of many chemistry students’ studies. It’s so easy to get tangled up in a jumble of numbers without any idea of what’s actually going on.
I just want to be a doctor, so does organic chemistry really matter?
Imagine: you’ve made it through your first semester or two of undergrad and weathered all the storms that come with this transition. And, now you find yourself facing a dreaded academic giant that has stricken fear in the hearts of scores of pre-medical students. A chemistry course unlike any other. If you are anything like most pre-medical ...
So, what is chemical engineering for, anyway?
Chemical engineering is a comprehensive and vast field of study with far-reaching impact. I have been a practicing chemical engineer in the biotechnology industry for the last 5 years, and prior to that, I earned my doctorate in chemical engineering at the University of Wisconsin, Madison. Over the last 10 years, I have seen the evolution and ...
Complex solution composition problems: knowing where to start
Thanksgiving dinner conversations can be uncomfortable… but solution composition problems don’t have to be! Recall that a solution is a homogenous mixture of two or more substances. Chemists have come up with many ways to describe the composition of a solution. Some ways are more appropriate than others depending on the situation. 
Dimensional analysis: why the factor-label method is a lifesaver
Ever lost points on a test because you forgot to write the units? Rightfully so! Numbers have no meaning without their units of measurement. Two can be greater than 12. Three can equal one. This is all dependent on the unit of measurement being used. In your general chemistry class, you will encounter measurements of all sorts. These measurements ...
Formal charge: what they didn’t tell you in your chemistry class
Formal charge is the charge that a bonded atom would have if its bonding electrons were shared equally. Note:
Orgo 2 strategies: “taking home” carboxylic acid derivatives
I’ve already covered how to easily manage carboxylic acid derivative formation and manipulation using the Reactivity Hill. Say we’re tired of whatever derivative we just created and want to bring the derivative back to its parent acid (the particular acid the derivative came from). There are two ways to “take home” any acid-derivative. We can ...
Golden rules to nuclear magnetic resonance spectroscopy (NMR) analysis: part 1
Nuclear magnetic resonance spectroscopy, or NMR, is a fundamental analytical technique used by chemists to determine the structure of organic compounds. Unlike other analytical techniques, such as infrared spectroscopy or mass spectroscopy, NMR allows for the complete interpretation of molecular structure and can be quantitative.
Two ways to determine equilibrium position in organic chemistry
A common exam question that comes up in both Orgo 1 and Orgo 2 requires students to determine a reaction’s equilibrium position. The question usually looks something like this: 
Orgo 1 strategies: finding and comparing alkene hydration products
We all know Orgo 1 professors love stereoisomers. Consider the equation A + B = C. Most professors expect you to fill in the question mark with all possible products and then indicate the major product(s), while other professors may provide you a potential C and then ask you if the statement is True or False.
How to get oriented to organic chemistry: 7 pillars of the course
Organic Chemistry (OChem or Orgo) seems like a scary course. But it should not be if you know what to expect. This road map is your guide to orientate yourself to Orgo1. It teaches you about the main topics covered in Orgo1 in the typical order they are taught in class. So, take a breath and sit back as you read, skim, or view the images that ...
Orgo 1 strategies: protocol for acid-base problems
  Determining which of two molecules is more acidic is tricky if you haven’t yet organized those factors that influence acidity. The protocol is a method I learned from my mastermind Orgo 2 professor to keep these ideas in order when they come into conflict. Namely: Size is more important than Electronegativity, which is more important than ...
What is the phospholipid bilayer and what determines its fluidity?
All cells are surrounded by a cell membrane that forms a barrier between the cell and its surroundings. This membrane is often referred to as the phospholipid bilayer. As you can probably tell from the name, a phospholipid bilayer is made up of two layers of lipids. The fluidity of this membrane must be maintained within a certain range for the ...
Tips and mnemonics for memorizing amino acid structures
Learning amino acid structures is a challenging part of biology and biochemistry coursework. Many students feel totally overwhelmed by the task. The best way to master this skill is lots of repetition (here is a link to a Sporcle quiz that may help you with the repetition part) but it can be helpful to have tricks and mnemonics to get you started. ...
topicTopics
academics study skills MCAT medical school admissions SAT expository writing college admissions English MD/PhD admissions GRE GMAT LSAT chemistry writing strategy math physics ACT biology language learning test anxiety graduate admissions law school admissions MBA admissions interview prep homework help creative writing AP exams MD study schedules summer activities history personal statements academic advice career advice premed philosophy secondary applications Common Application computer science organic chemistry ESL PSAT economics grammar test prep admissions coaching law statistics & probability supplements psychology SSAT covid-19 legal studies 1L CARS logic games reading comprehension Spanish USMLE calculus dental admissions parents research Latin engineering verbal reasoning DAT excel mathematics political science French Linguistics Tutoring Approaches chinese DO MBA coursework Social Advocacy academic integrity case coaching classics diversity statement genetics geometry kinematics medical school skills IB exams ISEE MD/PhD programs PhD admissions algebra astrophysics athletics biochemistry business business skills careers data science letters of recommendation mental health mentorship quantitative reasoning social sciences software engineering trigonometry work and activities 2L 3L Academic Interest Anki EMT English literature FlexMed Fourier Series Greek Italian Pythagorean Theorem STEM Sentence Correction Zoom algorithms amino acids analysis essay architecture art history artificial intelligence cantonese capacitors capital markets cell biology central limit theorem chemical engineering chromatography climate change clinical experience cold emails community service constitutional law curriculum dental school distance learning enrichment european history finance first generation student fun facts functions gap year harmonics health policy history of medicine history of science information sessions institutional actions integrated reasoning intern international students internships investing investment banking logic mandarin chinese mba meiosis mitosis music music theory neurology operating systems phrase structure rules plagiarism poetry pre-dental presentations proofs pseudocode school selection simple linear regression sociology software study abroad teaching tech industry transfer typology units virtual interviews writing circles