Acid/Base Unit
April 27-May 6 (2016)
Day 1: Conjugate Acid/Base Pairs
Objectives (SWBAT):
Physical Science 31- Describe chemical changes and reactions using diagrams and descriptions of the reactant and
products
Evaluated by:
Conjugate Acid/Base Practice
Class structure:
Do Now: How do you recognize an acid from its formula.
1. Engage- Class will review the Arrhenius definitions of acids and bases (common definitions) then the
teacher will introduce the Bronsted-Lowry definitions of acids and bases.
2. Explore- Students will label compounds in a reaction as acids or bases based on proton movement.
3. Explain- Students will draw brackets to indicate acid/base pairs.
4. Elaborate- Students will predict partners in conjugate acid/base pairs and write equations.
Summary: Acids and Bases are types of solutions with specific properties. Acids are proton donors, and their formula
usually starts with H. Bases are proton acceptors and usually have a formula ending in OH.
Day 2: pH Lab
Objectives (SWBAT):
Physical Science 32- Determine the concentration hydronium in an unknown acid or base (pH level) by using data from a
laboratory investigation
Inquiry 5-Students will use organizational skills to build their own pH scale for future reference
Evaluated by:
pH Lab
Class structure:
Do Now: Identify the acid, base, conjugate acid, and conjugate base below.
H2O + OH -1  H3O+1 + H2O
1. Engage- Teacher will introduce the vocabulary word amphoteric regarding water. Students will review
the safety precautions for the day’s lab and check their partners for safety compliance
2. Explore- Students will test the pH of various solutions with universal pH paper, red litmus, and blue
litmus paper.
3. Explain- Students will explain the terms acid, base, and neutral using the notes from Day 1.
4. Elaborate- Students will create a pH reference scale for themselves comparing household substances.
Summary: Acids are sour, have a low pH, and turn litmus paper red. Bases are bitter, have a high pH, and turn litmus
paper blue.
Day 3: pH Calculations
Objectives (SWBAT):
Physical Science 32- Determine the concentration of an unknown acid or base by using data from a titration with a
standard solution and an indicator
Physical Science 33- Calculate pH of acids and bases using the concentration of hydronium and hydroxide ions
Inquiry 5- Use mathematics to solve problems
Evaluated by:
pH Calculations and Intro to Titrations
Class structure:
Do Now: What type of pH would hand soap have?
1. Engage- The class will review the main ideas from Day 2’s lab- pH scale, properties of acidic solutions,
properties of basic solutions, and properties of neutral solutions.
2. Explore- Students will calculate pH, pOH, [H+], and [OH] from data and use this to distinguish between
acidic and basic solutions.
3. Explain- Teacher will introduce the terms “strong” and “weak” for acids and bases and demonstrate how
this affects pH. Students will continue these calculations, showing all work.
4. Elaborate- Teacher will introduce titrations and students will complete pre-lab questions for Day 4.
Summary: Strong acids and bases dissociate completely in water to produce the maximum amount of H or OH. Weak
acids and bases do not dissociate completely and thus a larger concentration is needed to achieve the same pH.
Day 4: Titration Lab Part 1
Objectives (SWBAT):
Physical Science 32- Determine the concentration of an unknown acid or base by using data from a titration with a
standard solution and an indicator
Physical Science 33- Calculate pH of acids and bases using the concentration of hydronium and hydroxide ions
Inquiry 5-Use mathematics and graphing skills to solve problems
Evaluated by:
Titration Lab Part A
Class structure:
Do Now: Calculate the [H+], pOH, and [OH-] of a solution with a pH of 12.5.
1. Engage- Teacher will check the titration prelab problems as students log into their computers and gizmo
to complete a warm-up.
2. Explore- Students will perform a titration of a strong acid and strong base to determine the
concentration of the base.
3. Explain- Students will explain what the indicator means and how it is represented on the graph.
4. Elaborate- Students will perform a second strong and then a weak titration on day 5.
Summary: A titration is when an acid and base are reacted together until the solution is neutralized (equivalence point).
The concentration of one solution is known and volumes of both are known. This information can be used to calculate
the concentration of the unknown solution.
Day 5: Titration Lab Part 2
Objectives (SWBAT):
Physical Science 32- Determine the concentration of an unknown acid or base by using data from a titration with a
standard solution and an indicator
Physical Science 33- Calculate pH of acids and bases using the concentration of hydronium and hydroxide ions
Inquiry 5-Use mathematics and graphing skills to solve problems
Evaluated by:
Titration Lab Parts B and C
Class structure:
Do Now: Log into the computer and into gizmo.
1. Engage- Students will complete questions 1-3 of activity B on the titration lab.
2. Explore- Students will calculate the concentration of the acid and its pH.
3. Explain- Students will explain the difference in titration experiments and graphs for strong and weak
acid titrations.
4. Elaborate- Students will work on their acid/base review for additional practice.
Summary: Titrations rely on the use of an indicator to tell the technician when the endpoint (and therefore equivalence
point) has been reached. When a strong acid a base is mixed, this point is near neutral, 7 on the pH scale. When the
acid is stronger, the point is in the acidic range of the pH scale. When the base is stronger, the point is in the basic range
of the pH scale. This is important to know so that the correct indicator can be chosen- one that changes color in the
appropriate range.
Day 6: Catch up day from EOC testing
Objectives (SWBAT):
Physical Science 31- Describe chemical changes and reactions using diagrams and descriptions of the reactant and
products
Physical Science 32- Determine the concentration hydronium in an unknown acid or base (pH level) by using data from a
laboratory investigation
Physical Science 33- Calculate pH of acids and bases using the concentration of hydronium and hydroxide ions
Inquiry 5-Students will use organizational skills to build their own pH scale for future reference
Evaluated by:
Old Work from Acid/Base Unit
Class structure:
Do Now: Find the section of the room marked for the day you missed class for an EOC and complete the makeup
assignment.
1. Engage- Students will look at their calendars to find the days they missed class and sit in the appropriate
area.
2. Explore- Students will complete the make-up assignment and turn it in by the end of class.
3. Explain- Students will show all work on assignments.
4. Elaborate- Students will work on the test review (due Day 7) for additional practice.
Summary: Solutions have different properties that the solvent (boiling point elevation, freezing point depression,
conductivity) but this unit has focused on ability to change litmus paper, taste, and potential dangers of acids and bases.
These are solutions with high H+ concentrations or high OH- concentrations.
Day 7: Review for Acid/Base Test
Objectives (SWBAT):
Physical Science 31- Describe chemical changes and reactions using diagrams and descriptions of the reactant and
products
Physical Science 32- Determine the concentration hydronium in an unknown acid or base (pH level) by using data from a
laboratory investigation
Physical Science 33- Calculate pH of acids and bases using the concentration of hydronium and hydroxide ions
Inquiry 5-Students will use organizational skills to build their own pH scale for future reference
Evaluated by:
Review for Acid/Base Test
Class structure:
Do Now: Write a test question about titrations that could appear on your test tomorrow.
1.
2.
3.
4.
Engage- Teacher will review the list of study topics on the board with student suggestions.
Explore- Teacher will discuss the answers to the test review.
Explain- Teacher will show all work during the discussion of the review questions.
Elaborate- Teacher will also review vocabulary and test layout.
Summary: This is our last unit for the year and will close with a test on Day 8. This is your final chance, aside from the
exam review, to affect your Chemistry grade. Be prepared.
Day 8: Acid/Base Test
Objectives (SWBAT):
Demonstrate at least 67 % proficiency on the standards of this unit.
Evaluated by:
Test- Acids and Bases
Class structure:
Do Now: Take out a calculator and something to write with, open your binder to the table of contents and place
it on the back bench, move your bags to the A/C, and clear your calculator RAM
TEST
Summary: The upcoming exam will cover all material since January. Please begin studying as soon as possible.
Testing Preparation
GLE
Objective
Day(s) Addressed
Inquiry 5
Utilize mathematics to solve problems
2, 3, 4, 5, 6, 7
Physical
Science 31
Describe chemical changes and reactions using diagrams and descriptions of the
reactant and products
1, 6, 7
Physical
Science 32
Determine the concentration hydronium in an unknown acid or base (pH level) by
using data from a laboratory investigation
2, 3, 4, 5, 6, 7
Physical
Science 33
Calculate pH of acids and bases using the concentration of hydronium and
hydroxide ions
3, 4, 5, 6, 7
Vocabulary
Acid (Arrhenius and Bronsted-Lowry)
Base (Arrhenius and Bronsted-Lowry)
Amphoteric
Strong (acid or base)
Weak (acid or base)
Equations
pH= -log[H+]
pOH= -log[OH-]
Assessment Design
Basic: 6 Questions
Titration
Endpoint
Equivalence Point
Indicator
pH + pOH= 14
NaVa=NbVb
Standard: 12 Questions
Expanded: 6 Questions
Essential Skills and Learning Objectives
Type of
Question
(MC, CR, P)
Basic
(Remember &
Understand)
Standard
(Apply &
Analyze)
Expanded
(Evaluate &
Create)
Predict conjugate acid-base pairs and write equations for
the reactions
Calculate the [H+], pOH, and [OH-] of a solution
MC/CR
2 MC
2 MC
2 CR
MC/CR
MC/CR
1 MC
4 CR
5 CR
2 CR
Evaluate data from a titration (numbers and graphs) to
choose indicators for reactions and calculate the
concentration and pH of an unknown solution
1 MC
1 CR
1 MC
1 CR
2 CR