Problem Types

In today's classrooms, Higher Order Thinking Skills (HOTS) are evaluated by both homework and in-class quizzes and exams. Obviously, in-class activities have the added benefit of being monitored to ensure that the submitted work reflects the true ability of the learner. But, it is technologically possible to create an online homework system that reports a reasonably accurate assessment of the learner's ability. The key is to randomly assign similar questions such that no two students have the same problems and that any help obtained on a problem will require the "helper" to demonstrate their thinking process from start to finish. Even in algorithmically generated questions, this is not the case. Algorithmically generated questions are a widely used approach in many online homework systems, but "short-cuts" are possible to "get the answer". Homework problems in the Chem21 approach are grouped into "problem groups" (with 3 - 10 questions in each group) that covers the major topics of each chapter. A student's homework assignment will contain 1 or 2 randomly selected problems from each of the "problem groups". This approach to generating a homework assignment guarantees that each student has a different problem set while covering the same material. There are a variety of problem types available and an overview of each type follows:

  1. Multiple Choice - 2 to 25 choices are possible for each question

  2. Short Answer (or Fill-in-the-Blank) - if a student enters an incorrect answer, the program will display to the student all the characters at the beginning and ending of the answer that they entered correctly. This information gives the student immediate feed-back on where they made a mistake. This problem type is used extensively for naming compounds in both General and Organic Chemistry.

  3. Unordered Text Answers - this problem type is used for drawing isomers and resonance structures where the answers can be entered in any order.

  4. Balancing Chemical Equations - an equation template has been developed that contains 4 pieces of information for each chemical species: coefficient, chemical formula, charge and physical state. Instructors can eassily customize this template such that the first assignment may require the student to enter the coefficient; a second assignment may require the student to enter the chemical formula and coefficient, a third assigment may require the student to enter an ionic equation (students must supply the charges and physical states), and a fourth assigment may require the student to enter a net ionic equation.

  5. Balancing Nuclear Equations - a slightly different template has been developed that contains 4 pieces of information for each species: coefficient, atomic number, mass number and chemical symbol. Both the chemical equation and nuclear equation templates provide immediate feedback to the student when incorrect information is entered - the incorrect entry is surrounded by a red box.

  6. Multiple Short Answers - this problem type is used for multi-part questions like

    How many protons, neutrons, and electrons reside in a Cr3+ ion that has a mass number of 53?

    The Lewis Structure of C2H2 contains ___ electrons, ___ π electrons, ___ σ electrons and ___ non-bonding electrons.


  7. Numeric Answers - this problem type requires a numeric answer that the computer evaluates to see if it falls within the tolerance established by the instructor.