I want YOU to participate in the USNCO!

Passionate about chemistry, I have participated in a prestigious science competition known as the USNCO. In this post, I will provide key information on how to crack the USNCO. Hope this benefits you and Merry Christmas!

About USNCO

USNCO or United States National Chemistry Olympiad is a chemistry competition for high school students that starts of at the local levels, then the national level, and finally the international level. Moving up levels requires an excellent performance at the previous levels.

Local Level

At the local level, there is only one exam - the aptly named local exam. A multiple-choice exam with 60 questions and a time limit of 110 minutes, the local exam covers a wide variety of topics, most of which are AP Chemistry exam topics. However, the difficulty in this exam comes from the questions that cover topics not on the AP Chemistry exam and the questions that involve clever applications of AP Chemistry exam concepts. If you do well, you will proceed to the national level. However, if more than two students from your school qualify to proceed to the national level, then only the two highest scoring students will proceed to the national level. When I attempted USNCO last year, 3 students from my school qualified that included me, but unfortunately I could not make it to the national level because of this rule.

National Level

At the national level, there are three national exams that must be taken (it’s one national exam with three parts, but it truly feels like three exams).

The first part/exam is another multiple-choice exam. The topics are not that much different than those at the local level, but the questions get significantly more difficult and sometimes require some insane ways of applying concepts. Even more challenging is the time constraint, 60 questions again, but now you only have 90 minutes to complete them. At the end of the exam there is a quick survey that you can complete, and it does not affect your score on the exam.

The second part/exam is composed of eight free-response questions (eight questions with MANY parts, that is) and has a time limit of 105 minutes. The difficulty is on par with the first part/exam, but now you cannot rely on lucky guesses to score you a few extra points.

The final part/exam is a lab practical. A lab practical is where you will perform an actual lab procedure or experiment to collect data to answer some lab questions given to you. In this lab practical you are given two questions (again, with many parts to each question) to complete within 90 minutes. If you really hit it out of the park, if you are in the top 20 at the national level, welcome to study camp.

Study Camp

This is the final level before the famous International Chemistry Olympiad (IChO). This study camp is full of intense studying and practice. The top four students in study camp will represent the United States team in IChO.

IChO

AP Chemistry topics will not cut it anymore. There is not much information about IChO, but the few recent IChO exams that I have reviewed are beyond anything I have ever seen. Physical chemistry, biochemistry, materials chemistry, no field of chemistry is left out.

How to prepare

If you aspire to make it to the national and international levels of the Chemistry Olympiad, keep reading. Preparing for USNCO requires knowledge of many topics. Practice the topics listed below to ensure that you can complete USNCO exams within their time limits:

Stoichiometry & Solutions

Stoichiometry is often tested in questions 1-6 of USNCO multiple-choice exams. Stoichiometry is not difficult to learn, as it is applying basic arithmetic and algebra to quantify various amounts in chemistry. The difficulties that come with stoichiometry problems in USNCO exams include whether you can find the shortcut to solve the question quickly and the presence of other topics that are mixed with stoichiometric problems. A strong knowledge of solutions is also required. Knowledge of solutions includes solubilities of salts and the dissolution of salts.

Descriptive/Laboratory

Descriptive/Laboratory chemistry is often tested in questions 7-12 of USNCO multiple-choice exams. Knowledge of descriptive/laboratory chemistry includes the uses of various laboratory glassware, the color of ions in solution, the flame test, reactions of different elements and compounds in liquids, error analysis, iodometry, and many other analytical techniques.

States of Matter

States of matter are often tested in questions 13-18 of USNCO multiple-choice exams. Knowledge of states of matter is very broad, including ideal and non-ideal gas laws, intermolecular forces, boiling points, crystal structures, phase changes, and phase diagrams.

Thermodynamics

Thermodynamics is often tested in questions 19-24 of USNCO multiple-choice exams. Knowledge of thermodynamics includes comparison of thermodynamic properties for various substances at various phases of matter and equations for heat/enthalpy, entropy, and Gibbs free energy.

Kinetics

Kinetics is often tested in questions 25-30 of USNCO multiple-choice exams. Knowledge of kinetics includes the equation for the rate of a reaction, determining the change in concentrations of an occurring reaction, determining what the rate of a reaction is dependent upon, and the various properties of kinetically different reactions.

Equilibria

Equilibria are often tested in questions 31-36 of USNCO multiple-choice exams. Knowledge of equilibria include Le Chatelier’s principle, determining whether a reaction is at equilibrium or not, equations involving the equilibrium constant, and determining the concentrations and pressures of both reactants and products at equilibrium.

Redox

Redox is often tested in questions 37-42 of USNCO multiple-choice exams. Knowledge of redox includes oxidation states, determining oxidants and reductants, balancing redox reactions, electrochemistry, and any equations related to cell potentials in electrochemistry. This section tends to be difficult.

Atomic Structure/Periodicity

Atomic structure/periodicity is often tested in questions 43-48 of USNCO multiple-choice exams. Knowledge of atomic structure/periodicity includes electron configurations, quantum numbers, periodic trends, fundamental principles about electrons, various atomic models and their equations, and radioactive decay.

Bonding/Molecular Structure

Bonding/molecular structure is often tested in questions 49-54 of USNCO multiple-choice exams. Knowledge of bonding/molecular structure includes VSEPR theory, MO theory, valence bond theory, hybridization, dipoles, crystal field theory, and isomers in coordination compounds.

Organic/Biochemistry

Organic/biochemistry is often tested in questions 55-60 of USNCO multiple-choice exams. Knowledge of organic/biochemistry includes organic chemistry I, II, and III.

Knowledge of all these topics will also help you answer the free-response exam at the national level. Lab experience prior to the lab practical exam at the national level is highly recommended.

Tips and Tricks

The only tips and tricks for this competition are the tried-and-true ones that I am listing below:

• Do the easy questions first.
• Guess if you do not know the answer to the question.
• If you can, avoid using intuition. Many of the questions can be misleading if math is involved.
• There is a time constraint, dwelling is a surefire way to failure. Be mindful of time.

Resources

There is a lot to know to compete in USNCO. I found the below resources helpful in the preparation:

General Chemistry

• A good starting point is the book Chemistry by Zumdahl
• Chemical Principles: The Quest for Insight by Atkins is challenging, but definitely worth studying.

Organic Chemistry

• Start here on the Master Organic Chemistry website
• Organic Chemistry by Klein is a good read
• Aspiring for IChO? Read Organic Chemistry by Clayden

Other Resources

• CODSite for all other competitive chemistry needs
• Insightful videos from CODSite
• Past USNCO exams that can be done for practice and prep

Good luck, and may the best chemists win.