Skip Navigation

ACS is committed to helping combat the global COVID-19 pandemic with initiatives and free resources. Learn More

USNCO Exams - Reference Page

Below is the standard information that is provided as reference for all USNCO exams. No additional information may be accessed while taking any USNCO exam.

Abbreviations and Symbols

Full Name Abbreviation/Symbol
amount of substance n
ampere A
atmosphere atm
atomic mass unit u
Avogadro constant NA
Celsius temperature °C
centi– prefix c
coulomb C
density d
electromotive force E
energy of activation Ea
enthalpy H
entropy S
equilibrium constant K
Faraday constant F
free energy G
frequency ν
gas constant R
gram g
hour h
joule J
kelvin K
kilo– prefix k
liter L
measure of pressure mm Hg
milli– prefix m
molal m
molar M
molar mass M
mole mol
Planck’s constant h
pressure P
rate constant k
reaction quotient Q
second s
speed of light c
temperature, K T
time t
vapor pressure VP
volt V
volume V

Constants

R = 8.314 J mol–1 K–1
R = 0.08314 L bar mol–1 K–1
F = 96,500 C mol–1
F = 96,500 J V–1 mol–1
NA = 6.022 x 1023 mol–1
h = 6.626 x 10–34 J s
c = 2.998 x 108 m s–1
0 °C = 273.15 K
1 atm = 1.013 bar = 760 mm Hg
Specific heat capacity of H2O = 4.184 J g–1 K–1

Equations

E = Eo(RT/nF) x lnQ

lnK = (—ΔHo/R) x (1/T) + constant

ln(k2/k1) = (Ea/R) x ((1/T1) — (1/T2))

 

Periodic Table of the Elements

Thank you to the Olympiad Examinations Task Force

  • Seth N. Brown, Chair, University of Notre Dame, Notre Dame, IN
  • James Ayers, Colorado Mesa University, Grand Junction, CO
  • Jerry Bell, Simmons University, Boston, MA (retired)
  • Mark DeCamp, University of Michigan, Dearborn, MI (retired)
  • Joshua de Groot, College of Southern Idaho, Twin Falls, ID
  • James Dohm, Vanderbilt University, Nashville, TN
  • Xu Duan, Holton-Arms School, Bethesda, MD
  • Valerie Ferguson, Moore HS, Moore, OK
  • Julie Furstenau, Thomas B. Doherty HS, Colorado Springs, CO (retired)
  • Kimberly Gardner, United States Air Force Academy, CO
  • Paul Groves, South Pasadena HS, South Pasadena, CA
  • Nicolas Hamel, Clackamas Community College, Oregon City, OR
  • David W. Hostage, Taft School, Watertown, CT
  • John Kotz, State University of New York, Oneonta, NY (retired)
  • Michael A. Morgan, Francisco Bravo Medical Magnet HS, Los Angeles, CA
  • Jane Nagurney, Scranton Preparatory School, Scranton, PA (retired)

Thank you to the Olympiad Laboratory Practical Task Force

  • Kelli Slunt, Chair, University of Mary Washington, Fredericksburg, VA
  • Payton Bailey, University of Mary Washington, Fredericksburg, VA
  • Jesse Bernstein, Miami Country Day School, Miami FL (retired)
  • Alexsandra DaSilva, SUNY, Binghamton, NY
  • Myra Halpin, NC School of Science & Mathematics, Durham, NC (retired)
  • Nicolas Hamel, Clackamas Community College, Oregon City, OR
  • Innocent Pumure, University of Central Missouri, Warrensburg, MO
  • Lawrence Wilkinson, ExxonMobil, Baton Rouge, LA