Weight evaluator to grade chemistry answers

Updated 30 Aug 2024

Use the Weight evaluator (expressionOchemEvalWeight) to compare the molecular weight of the student’s response to the evaluator answer. The Rings evaluator works with the skeletal answer type.

  1. Select Grade as Correct or Grade as Incorrect, then enter the conditions you want to be checked in student answers.
  2. Select one of the following “if” conditions.
    • exact molecular weight
      Uses the most abundant isotopes of an element to calculate the mass of a molecule.
    • average molecular weight
      Uses the weighted average of the masses of all of an element's isotopes in the distribution found in the Earth's crust.
  3. Select an “is” condition, like exactly or other.

    exactly
    Student answer number = the number in this box

    more than
    Student answer number > the number in this box

    fewer than
    Student answer number < the number in this box

    not exactly
    Student answer number <> the number in this box

    fewer than or equal to
    Student answer number ≤ the number in this box

    more than or equal to
    Student answer number ≥ the number in this box

  4. Enter a real number and a range (∓).

    The plus or minus accounts for variations in significant figures and changes in the scientific precision of molecular weights. You must specify a range; no default range is provided.

    SymbolElementWeight
    HHydrogen1.00794
    HeHelium4.002602
    LiLithium6.941
    BeBeryllium9.012182
    BBoron10.811
    C Carbon12.0107
    N Nitrogen14.0067
    O Oxygen 15.9994
    F Fluorine18.9984
    Na Neon 20.1797
    Na Sodium22.98977
    Mg Magnesium 24.305
    Al Aluminum26.98154
    Si Silicon 28.0855
    P Phosphorus 30.97376
    S Sulfur 32.065
    Cl Chlorine35.453
    Ar Argon 39.948
    K Potassium39.0983
    Ca Calcium 40.078
    Sc Scandium 44.95591
    TiTitanium 47.867
    V Vanadium50.9415
    Cr Chromium 51.9961
    Mn Manganese 54.93805
    FeIron 55.845
    CoCobalt58.9332
    Ni Nickel 58.6934
    Cu Copper 63.546
    Zn Zinc 65.409
    GaGallium69.723
    Ge Geranium 72.64
    As Arsenic 74.9216
    Se Selenium 78.96
    Br Bromine 79.904
    Kr Krypton 83.798
    Rb Rubidium 85.4678
    Sr Strontium 87.62
    Y Yttrium88.90585
    Zr Zirconium 91.224
    Nb Niobium 92.90638
    Mo Molybdenum 95.94
    Tc Technetium98
    Ru Ruthenium 101.07
    Rh Rhodium 102.9055
    Pd Palladium 106.42
    AgSilver107.8682
    Cd Cadmium 112.411
    In Indium 114.818
    Sn Tin 118.71
    SbAntimony121.76
    Te Tellurium 127.6
    I Iodine 126.9045
    Xe Xenon 131.293
    Cs Caesium132.9055
    Ba Barium 137.327
    la Lanthanum 138.9055
    Ce Cerium 140.116
    PrPraseodymium140.9077
    Nd Neodymium 144.242
    Pm Promethium 145
    Sm Samarium 150.36
    EuEuropium151.964
    Gd Gadolinium 157.25
    Tb Terbium 158.9254
    Dy Dysprosium 162.5
    HoHolmium162.9303
    Er Erbium 167.259
    Tm Thulium 168.9342
    Yb Ytterbium 173.04
    LuLutetium174.967
    Hf Hafnium 178.49
    Ta Tantalum 180.9479
    W Tungsten 183.84
    ReRhenium186.207
    Os Osmium 190.23
    Ir Iridium 192.217
    Pt Platinum 195.084
    AuGold196.9666
    Hg Mercury 200.59
    Tl Thallium 204.3833
    Pb Lead 207.2
    BiBismuth208.9804
    Po Polonium 209
    At Astatine 210
    Rn Radon 222
    FrFrancium223
    Ra Radium 226
    Ac Actinium 227
    Th Thorium 232.0381
    PaProtactinium 231.0359
    U Uranium 238.0289
    Np Neptunium 237
    Pu Plutonium 244
    AmAmericium243
    Cm Curium 247
    Bk Berkelium 247
    Cf Californium 251
    EsEinsteinium252
    Fm Fermium 257
    Md Mendelevium 258
    No Nobelium 259
    LrLawrencium262
    Rf Rutherfordium 261
    Db Dubnium 262
    SgSeaborgium 263
    Bh Bohrium 264
    Hs Hassium 265
    MtMeitnerium 268

Select Show this response to enter wrong answer feedback for when the student’s answer matches a Grade as Incorrect condition.

Use your keyboard and options from the editing toolbar and menus. Wrong answer and follow-up text can include an image, link, and formatted text like bullets or TeX.

 

See also:

Answer evaluators list (for correct or incorrect answers) | How grading evaluators work | Properties for the Marvin JS drawing tool setup