Biodiesel Lab (Classroom)

The Biodiesel Lab is an activity designed to introduce students to the chemistry of pH and acid/ base titrations through the lens of making biodiesel fuel. Biodiesel is a sustainable renewable energy source made from vegetable oil. Students will be guided to explore pH indicators and determine the percent composition of substances like vinegar all with materials they can find at home!

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Learning Objectives

Students will know

Molarity
Acids and base titrations
pH scale
pH indicators
Equivalence points within acid base reactions

Students will understand

How titration is used to determine molar concentrations
The balance between a reaction and the reverse reaction determines the numbers of all types of molecules present.
Matter is not lost through chemical reactions

Students will be able to

Search for natural pH indicating substances
Determine if substances are acidic or basic
Use conversion equations to find unknown variables, including unknown concentrations of solutions in Molar, percent composition and percent error within their solutions.
Neutralize acids and bases through titration experiments
Practice precise measuring

Standards Alignments

Next Generation Science Standards

HS-PS1-5 Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.

HS-PS1-6 Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium.

HS-PS1-7 Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.

Texas Essential Knowledge and Skills Connections

Process Standards

CHEM.2(F): collect data and make measurements with accuracy and precision;

CHEM.2(G): express and manipulate chemical quantities using scientific conventions and mathematical procedures, including dimensional analysis, scientific notation, and significant figures;

Concept Standards

CHEM.8(A): define and use the concept of a mole;

CHEM.8(C): calculate percent composition of compounds;

CHEM.8(F): differentiate among double replacement reactions, including acid-base reactions and precipitation reactions, and oxidation-reduction reactions such as synthesis, decomposition, single replacement, and combustion reactions;

CHEM.10(C): calculate the concentration of solutions in units of molarity;

CHEM.10(E): distinguish among types of solutions such as electrolytes and nonelectrolytes; unsaturated, saturated, and supersaturated solutions; and strong and weak acids and bases;

CHEM.10(H): define pH and calculate the pH of a solution using the hydrogen ion concentration.

Louisiana Standards for Science Connections

HS-PS1-5: Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.

HS-PS1-6: Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium.

HS-PS1-7: Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.

Unit Plan

Pre-Laboratory Engagement

Pre-Laboratory Engagement (30 minutes)

Students will be introduced to the pH scale and biodiesel as they watch the Khan Academy video (5:21), read a short article from Newsela, and watch the Biodiesel Education video (5:39).
Students will answer corresponding questions on their pre-laboratory handout.
Students will create an edible indicator from red cabbage and use it to determine the acidity or alkalinity of substances at home. Edible pH Indicator Student Handout

Laboratory Exploration

Laboratory Exploration (30-40 minutes)

Students watch the introductory lab video “Biodiesel Part One” (4:42)
• Students will answer the first three questions on page one of the lab handout.
Students will watch the lab video “Biodiesel: Part Two” (4:37)
• Students will answer quick check questions and fill in data for Part II and III of the lab handout.
After the video, students will complete part IV, V, and VI of the lab activity handout on their own.
• Students view the worksheet walkthrough to help them answer the questions and learn the material.
• Video can be supplied before or after student work is submitted

Post-Laboratory Extension

Post-Laboratory Extension (30-45 minutes)

Students will conduct a titration of vinegar with baking soda to determine the percent composition of acetic acid in vinegar and compare their measurements to commercial standards.
• At Home Titration Student Procedure and Worksheet

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