Create chemPad Questions for Formulas

When you create chemPad questions that are answered with a chemical formula, you can choose whether to allow chemically equivalent responses or to require your students to enter the standard formula that matches your answer key. You can also create chemPad questions for which the correct response is the keyword NONE.

You can enable support for specific kinds of chemically equivalent notation in your students' responses:

  • For some introductory chemistry questions, you can let your students specify elements in any order, for example, either CH4N2O or CN2H4O.
  • You can let your students enter condensed formulas such as (NH2)2CO for CH4N2O. Allowing condensed formulas also allows potentially undesirable variations like HNHCHNHO.
  • You can let your students enter charges with the sign either preceding or following the value, such as Mg2+ or Mg+2.
  • You can let your students specify ionizable protons either at the beginning of the formula or in their standard place, such as CH3CO2H or HCH3CO2.
  • You can let your students use alternative nuclear particle names, such as β or e, and specify nuclide superscripts and subscripts in either order, for example, by typing either ^0_-1beta or _-1^0beta to display 0-1 β.
  • You can let your students enter solvate dot notation, such as CoCl2 · 2 H2O.
  • When the correct chemical formula must be stated in exactly one way — or if the answer is the keyword NONE — you can require your students' responses to exactly match your answer key.
  1. Click Questions > Create. The Question Editor opens.
  2. In Name, type a name for the question.
  3. In Mode, select Fill-in-the-Blank.
  4. In Question, type your question. Provide relevant information about assumptions or expectations for the question, for example, the conditions for the question — STP, SATP, or reaction/prevailing conditions — or whether states-of-matter should be specified in the response. Use the answer placeholder string <_> to specify where the answer box should be displayed.
  5. In Answer, type the following items on a single line:
    <EQN $PAD='chem'; $CHEM='method'; ''>answer_key 

    where answer_key specifies the correct answer to the problem, and method is one of the following chemPad parsing methods:  

    Allowed Notation

    Example

    Method

    Only exact key match

    CH4N2O

    none

    (specify $CHEM='none')

    Formula elements in any order

    CH4N2O or CN2H4O

    fmla

    Condensed formulas

    (NH2)2CO or CH4N2O

    fmla,index

    Ion charges

    Mg2+ or Mg+2 

    ion

    Ionizable protons first

    CH3CO2H or HCH3CO2 

    ion,acid

    Nuclear particles and nuclides

    β 1- 0 or e 1- 0

    nclr

    Nuclear particles with charges

    He 2+ 2 4
    nclr,ion

    Solvate dot

    CoCl2 · 2 H2O

    solvate

    For example:  

    Answer

    Code

    H2SO4

    <EQN $PAD='chem'; $CHEM='none'; ''>H_{2}SO_{4}

    HNO3

    <EQN $PAD='chem'; $CHEM='fmla'; ''>HNO_{3}

    CH4N2O

    <EQN $PAD='chem'; $CHEM='fmla,index'; ''>CH_{4}N_{2}O

    Mg2+ 

    <EQN $PAD='chem'; $CHEM='ion'; ''>Mg^{2+}

    NH4+ 

    <EQN $PAD='chem'; $CHEM='ion,acid'; ''>NH_{4}^{+}
    0-1 β

     

    <EQN $PAD='chem'; $CHEM='nclr'; ''>^{0}_{-1}beta

    CuSO4 · 6 H2O

    <EQN $PAD='chem'; $CHEM='solvate'; ''>CuSO_{4} . 6 H_{2}O
    Note
    • If an answer extends beyond the right side of the Answer box, it is wrapped to the next line, but it is still considered a single line so long as you do not press ENTER.
    • As with other fill-in-the-blank questions, you can specify alternative answer keys separated by the characters {tab}.
    • For information about how to specify chemical notation in your answer key, see Creating chemPad Answer Keys.
  6. Optional: Type a Solution.

    The solution helps your students understand the steps they need to take to determine the correct answer to the question. Your assignment settings specify when to show the solution.

  7. Click Test/Preview to test the appearance and behavior of the question. See Test Questions.
  8. Click Redisplay to show certain kinds of errors in the Display section of the Question Editor. Make any needed changes to your question.
  9. Optional: Click Show Additional Information and change the question's sharing permission or add descriptive information.
    • By default, other instructors can use your question only if you provide them with the question ID, and only you can edit the question or find it in search results. To change the permission, see Share Questions With Other Instructors.
    • If you make your question publicly available, you might want to provide descriptive information to help others search for it. See Add Search Metadata to Questions.
  10. When your question displays and functions correctly, click Save.

    WebAssign assigns it a unique question ID (QID), which is displayed in parentheses after the question name.

    You can use your question in an assignment and see it in your My Questions list only after it is saved.

Example chemPad Question (Allow Equivalent Formulas)

The following table summarizes an actual question.

QID

1534325

Name

Template2 5.CHEMP.01.

Mode

Fill-in-the-Blank

Question

Write the formula for the product of SO<sub>3</sub> + 
H<sub>2</sub>O. <br>
<_>

Answer

<EQN $PAD='chem'; $CHEM='fmla'; ''>H_{2}SO_{4}

Display to Students

Question as displayed to students

Example chemPad Question (Require Exact Key Matching)

The following table summarizes an actual question.

QID

1534329

Name

Template2 5.CHEMP.02.

Mode

Fill-in-the-Blank

Question

Provide the chemical formula for nitric acid. <br>
<_>

Answer

<EQN $PAD='chem'; $CHEM='none'; ''>HNO_{3}

Display to Students

Question as displayed to students

Example chemPad Question (Solvate)

The following table summarizes an actual question.

QID

1534314

Name

Template2 5.CHEMP.03.

Mode

Fill-in-the-Blank

Question

Provide the chemical formula for cobalt(II) chloride 
dihydrate.<br>
<_>

Answer

<EQN $PAD='chem'; $CHEM='solvate'; ''>CoCl_{2} . 2 H_{2}O

Display to Students

Question as displayed to students