# UTPA STEM/CBI Courses/Stoichiometry

Course Title: General Chemistry I

Lecture Topic: Stoichiometry

Institution: Texas A & M International University

## Backwards Design

Course Objectives

• Primary Objectives- By the next class period students will be able to:
• Explain the concepts
• Perform mole conversions
• Calculate the amount of a material needed to prepare another substance

• Sub Objectives- The objectives will require that students be able to:
• Balance chemical equation
• Calculations involving conversions from mole-gram and vice versa
• Calculations involving volume to mole using molarity

• Difficulties- Students may have difficulty:
• Converting given information to moles
• Using stoichiometry to deduce the mole of the required from the mole given

• Real-World Contexts- There are many ways that students can use this material in the real-world, such as:
• Stoichiometry is encountered when a student wants to prepare a particular dish using a recipe; or how much hamburger buns and patties are need to prepare hamburgers. or hamburgers with double patties. Using the right amount of ingredients in a recipe –scaling up or down
• Effectively planning a party

Model of Knowledge

• Concept Map
• Writing chemical formulas from names of compounds
• Writing chemical equations from chemical sentences
• Balancing chemical reactions
• Using dimensional analysis to introduce the mole concept
• Inter-conversions involving mole-gram-molar mass-molarity-volume
• Using dimensional analysis to write mole relationships between reactants and products
• Using the mole of a given substance to find the moles of a required substance

• Content Priorities
• Enduring Understanding
• Balancing chemical equation
• Calculate the amount(s) needed to make a compound
• Writing chemical compounds
• Dimensional analysis (unit conversions)
• Important to Do and Know
• Percent composition
• Limiting reactants
• Worth Being Familiar with
• Percent composition
• Density-mass-volume relationship

Assessment of Learning

• Formative Assessment
• In Class (groups)
• Group Assignments
• Presentations
• Homework (individual)
• Online homework
• Summative Assessment
• Report
• Quiz

## Legacy Cycle

OBJECTIVE

By the next class period, students will be able to:

• Write chemical equations from sentences and balance them
• Express quantities of substance given in mole

The objectives will require that students be able to:

• Set up a titration experiment
• Calculate an unknown from component

THE CHALLENGE

A food chemist determines the concentration of acetic acid in a sample of apple cider vinegar by acid–base titration. The density of the sample is 1.01 g/mL. The titrant is 0.0992 M NaOH. The average volume of titrant required to titrate 25.00 mL subsamples of the vinegar is 20.78 mL. What is the concentration of acetic acid in the vinegar? Express your answer the way a food chemist probably would: as percent by mass.

GENERATE IDEAS

Students engage in brainstorming: titration, given information; equation of the chemical reaction; balance the equation; etc

MULTIPLE PERSPECTIVES

Students listen to lecture on mole concepts Students are left to use resources-SI leaders, discussion leaders, instructor; textbook

RESEARCH & REVISE

Students perform a similar titration experiment in the laboratory Students are directed to use resources-SI leaders, discussion leaders, instructor; textbook

Student present work in the learning communities

GO PUBLIC

Students have their poster on Glogster (Glogster.com)

## Pre-Lesson Quiz

Various material can be tested here, depending on time constraints.