Stoichiometry Skills Gateway Overview
Introduction
This Gateway is designed to insure that all students can do basic stoichiometry calculations
involving that include elements, compounds, atoms, ions and molecules:
1. Inter-conversion between mass and moles
2. Inter-conversion between volume and moles
3. Inter-conversion between number of entities and moles
4. Inter-conversion between moles (or between numbers of atoms, ions, molecules or
formula units) based on chemical formulas. For example determining the number of
oxygen atoms in a formula unit of copper nitrate or determining the moles of oxygen
atoms in a mole of copper nitrate.
5. Inter-conversion between moles (or between numbers of atoms, ions, molecules or
formula units of reactants and products in a reaction) based on chemical formulas.
In order to achieve the following students will learn to do the following amongst other skills.
1. Calculate molar mass and use it in mass-mole conversions.
2. Know the meaning and be able to use Avogadro’s number
3. Write and balance chemical equations
4. Calculate molarity and use it in volume-mole conversions. Be able to determine how
to prepare solutions of a desired molarity.
Copyright Notice
Sample Maple TA assignments (DRILLs and PRETESTs) are provided so that users of this
material can get an idea of the nature of the online assignments. Questions were selected
algorithmically so the assignment could be retaken numerous times with each instance being
unique. For this reason two versions of the assignments are usually provide to demonstrate
variations between repeat assignments Some of the questions may be taken from question banks
provided with the Prentice Hall GradeAssisst (PHGA) online homework system and may be
copyright protected. These assignments are provided only as samples.
Components of the Stoichiometry Skill Gateway
Laboratory
The principle mechanism for introducing the concepts of the Stoichiometry Skill Gateway
was the Track 2 Lab components. A complete description of the redesigned lab curriculum is
given in the document “README_Comments_on_Redesign_Lab.doc”. The labs that
contributed to the development of the Stoichiometry Skill Gateway Concepts will be listed
briefly here.
Week 4 Lab: “Determining the Concentration of Sugar in a Commercial Beverage”
The concepts of mole and molarity are introduced here to allow the concentration of
sugar to be expressed in molarity.
Week 5 Lab: “Chemical Reactions I: Some Chemical Reactions Involving Oxygen”
Students learn and practice writing and balancing chemical equations.
Week 6 Lab: “Chemical Reactions II: Reactions of Ions in Solution”
Students gain additional practice writing and balancing chemical equations.
Week 7 Guided inquiry activity: “Counting Numbers of Atoms and Molecules – POGIL
Activity” and “Molar Mass” lab. This lab provides thorough coverage of the mole
concept, meaning and use of Avogadro’s number, molar mass and formula and reaction
stoichiometry.
Week 8 “Determining the Percent Composition of Potassium Chlorate in a Mixture” and
“Titration of Vinegar” labs
Students learn both gravimetric and solution stoichiometry.
Module 1: “Moles and Molar Mass”
Module Assessments
DRILL - Stoichiometry I: atoms and elements
Students practice conversions between grams, moles and numbers of atoms using the
molar masses of elements.
Two samples generated by the online homework system are provided.
May contain copyrighted questions from PHGA online homework system.
Version 1: “DRILL - Stoichiometry I: atoms and elements No 1.pdf”
Version 2: “DRILL - Stoichiometry I: atoms and elements No 2.pdf”
DRILL - Stoichiometry 2: Compounds and Formulas
Students practice conversions between grams, moles and numbers of atoms, ions or
molecules in compounds.
Two samples generated by the online homework system are provided.
May contain copyrighted questions from PHGA online homework system.
Version 1: “DRILL - Stoichiometry 2: Compounds and Formulas No 1.pdf”
Version 2: “DRILL - Stoichiometry 2: Compounds and Formulas No 2.pdf”
Module 2: “Reaction and Solution Stoichiometry”
Module Assessments
Students practice stoichiometry problems involving chemical reactions both in terms of
mass and molarity of reactants and products. The reaction arrow (→) appears as a
in
this printouts. This is a result of changing html standards in the evolving Maple TA
software. These changes were an ongoing hindrance to advancement during the course
redesign.
DRILL Reaction Stoichiometry #1
Two samples generated by the online homework system are provided.
May contain copyrighted questions from PHGA online homework system.
Version 1: “DRILL Reaction Stoichiometry #1 No 1.pdf”
Version 2: “DRILL Reaction Stoichiometry #1 No 2.pdf”
DRILL Reaction Stoichiometry #2
Two samples generated by the online homework system are provided.
May contain copyrighted questions from PHGA online homework system.
Version 1: “DRILL Reaction Stoichiometry #2 No 1.pdf”
Version 2: “DRILL Reaction Stoichiometry #2 No 2.pdf”
Stoichiometry Gateway Exams
Stoich Skill Gateway Exam Opt 1.doc
Stoich Skill Gateway Exam Opt 2.doc
Note on Stoichiometry Skills Gateway
The online materials developed for the Stoichiometry Skills Gateway were limited by personnel
restraints. A more thorough Stoichiometry Skills Gateway is possible. Even with this limitation,
performance of students in the redesign section was similar to that of the control sections. This
is significant, due to the fact that these concepts were principally introduced in the lab
curriculum and reinforced with the gateway online homework, yielding similar results. This
supports one of the hypotheses of this project in demonstrating that computation and
stoichiometry can be developed independently in the lab curriculum.