BUFFER
iClicker Questions
Page 2: Ionization Reaction for Hydrobromic Acid
Identify the correct ionization reaction for hydrobromic acid (HBr). The options are:
A. $HBr(aq) ⇌ H^+(aq) + Br^−(aq)$
B. $HBr(aq) + H2O(l) ⇌ H3O^+(aq) + Br^−(aq)$
C. $HBr(aq) → H^+(aq) + Br^−(aq)$
D. $H^+(aq) + Br^−(aq) → HBr(aq)$
Page 3: Ionization Reaction for Acetic Acid
Identify the correct ionization reaction for acetic acid (HC₂H₃O₂). The options are:
A. $HC2H3O2(aq) ⇌ 4 H^+(aq) + C2O_2^{4−}(aq)$
B. $HC2H3O2(aq) + H2O(l) ⇌ H3O^+(aq) + C2H3O2^{−}(aq)$
C. $HC2H3O2(aq) → H^+(aq) + C2H3O2^{−}(aq)$
D. $H^+(aq) + C2H3O2^{−}(aq) → HC2H3O2(aq)$
Page 4: Ionization Reaction for Lithium Hydroxide
Identify the correct ionization reaction for lithium hydroxide (LiOH). The options are:
A. $LiOH(aq) → Li^+(aq) + OH^−(aq)$
B. $LiOH(aq) → LiO^−(aq) + H^+(aq)$
C. $LiOH(aq) ⇌ Li^+(aq) + OH^−(aq)$
D. $LiOH(aq) ⇌ LiO^−(aq) + H^+(aq)$
Page 5: Ionization Reaction for Ammonia
Identify the correct ionization reaction for ammonia (NH₃). The options are:
A. $NH3(aq) ⇌ H^+(aq) + NH2^{−}(aq)$
B. $NH_3(aq) ⇌ 3H^+(aq) + N^{3−}(aq)$
C. $NH3(aq) + H2O(l) ⇌ NH_4^+(aq) + OH^−(aq)$
D. $NH3(aq) + H2O(l) ⇌ NH2^{−}(aq) + H3O^+(aq)$
Page 6: Greatest H⁺ Concentration
Identify the solution that would result in the greatest H⁺ concentration. The options are:
A. 1.0 M HCl
B. 1.0 M NH₃
C. 1.0 M C₁₂H₂₂O₁₁
D. 1.0 M H₂CO₃
E. 1.0 M KOH
Page 7: Conjugate Acid-Base Pair
Identify a conjugate acid–base pair in the following reaction: HBr(aq) + H₂O(l) ⇌ H₃O⁺(aq) + Br⁻(aq) Options are:
A. H₂O (acid) and H₃O⁺ (base)
B. HBr (acid) and Br⁻ (base)
C. HBr (acid) and H₂O (base)
D. H₃O⁺ (acid) + Br⁻ (base)
Page 8: Another Conjugate Acid-Base Pair
Identify a conjugate acid–base pair in the following reaction: CH₃NH₂(aq) + H₂O(l) ⇌ CH₃NH₃⁺(aq) + OH⁻(aq) Options are:
A. CH₃NH₂ (acid) and CH₃NH₃⁺ (base)
B. CH₃NH₂ (acid) and H₂O (base)
C. CH₃NH₃⁺ (acid) and CH₃NH₂ (base)
D. CH₃NH₃⁺ (acid) and OH⁻ (base)
Page 9: Weak Acids and Conjugate Bases
As the strength of a weak acid increases, the strength of its conjugate base ____. Options are:
A. is constant
B. increases
C. decreases
D. can vary because conjugate base strength is unrelated to the strength of the acid
Page 10: pH and pOH Relationship
As the pH of a solution increases, the pOH of the solution ____. The options are:
A. is constant
B. increases
C. decreases
D. can vary because pH is unrelated to pOH
Page 11: General Form of Ka Expression
Identify the general form of the $Ka$ expression for the dissociation:
A. $Ka = \frac{[H3O^+][A^-]}{[HA]}$
B. $Ka = \frac{[HA]}{[H3O^+][A^-]}$
C. $Ka = \frac{[HA]}{[H2O][H_3O^+]}$
D. $Ka = \frac{[H2O]}{[HA][H_3O^+]}$
Page 12: Acidic Salt Solution
Identify the acidic salt solution:
A. CaBr₂
B. KNO₂(aq)
C. K₂SO₄(aq)
D. LiC₂H₃O₂(aq)
E. NH₄Cl(aq)
Page 13: Lewis Acid-Base Theory
According to Lewis theory ____. The possible statements are:
A. H⁺ is an acid because it donates electron pairs
B. H⁺ is an acid because it accepts electron pairs
C. H⁺ is a base because it donates electron pairs
D. H⁺ is a base because it accepts electron pairs
Page 14: Acid and Base Pairs
Example of acid-base pairs in reaction:
Reaction: $CH3COOH + H2O ⇌ CH3COO^{-} + H3O^+$
Acid: $CH_3COOH$
Base: $H_2O$
Conjugate acid: $H_3O^+$
Conjugate base: $CH_3COO^{-}$
Page 15: Acid and Base Ionization Constants
Equations:
$pKa = -\log{10}(K_a)$
For acids:
$HA + H2O ⇌ H3O^+ + A^-$
Acid ionization constant: $K_a$
For bases:
$B + H_2O ⇌ BH^+ + OH^-$
Base ionization constant: $K_b$
$pKb = -\log{10}(K_b)$
Water ionization constant:
$K_w = [H^+][OH^-] = 1.0 \times 10^{-14}$ at 25°C
Page 16: pH Calculations
Equations for calculations:
$pH = -\log[H^+]$
$pKa = -\log{10}(K_a)$
$pKb = -\log{10}(K_b)$
Page 17: Ionization Constants Relationship
The product of the ionization constant of an acid and the ionization constant of its conjugate base is equal to the ion-product constant of water:
Question: What is the $K_w$ value?
Page 18: RICE Table Example for HF
Reaction: $CH3COOH + H2O ⇌ CH3COO^{-} + H3O^+$
RICE Table:
Initial:
$CH_3COOH$: 0.50 M
$H^+$: 0
$CH_3COO^{-}$: 0
Change:
$CH_3COOH$: -$x$
$H^+$: $+x$
$CH_3COO^{-}$: $+x$
Equilibrium:
$CH_3COOH$: $0.50 - x$
$H^+$: $x$
$CH_3COO^{-}$: $x$
Page 19: Finalizing RICE Table for HF
Revisit the same reaction:
Use RICE table setup for calculating pH of 0.50 M HF when $K_a = 7.1 \times 10^{-4}$ at 298 K.
Page 20: Ionization of Weak Acids
The percentage of ionization of weak acids increases as their concentration decreases. For strong acids and bases, they are completely ionized at all concentrations.
Weak acids are 100% ionized at infinite dilution, i.e. $[weak acid] \approx 0M$.
Page 21: Fundamental Topics in Acid & Base Chemistry
Fundamental topics include:
Weak acids in water
Weak bases in water
Strong bases in water
Strong acids in water
Salts in water
Titrations
Buffers
Page 22: Definition of Salt
A salt is an ionic compound that contains a cation and an anion. The bonds are ionic. It is important to understand salts in the context of buffers.
Page 23: Ions and Electrons
Comparison between neutral atoms and ions:
Neutral atom: + -
Cation (positively charged ion)
Anion (negatively charged ion)
Mass Comparison:
Ions have mass greater than electrons, over 2000 times more.
Movement Comparison:
Which one is easier to move?:
A. Electrons
B. Ions
Page 24: pH Measurements in Different Solutions
Measurement of pH examples include:
pH = 7.0: pure water
After adding Acid: what happens to pH?
pH = 3.2: acidic solution
pH = 6.8: near neutral
pH = 11.5: basic solution
pH = 7.2: stable buffer solutions may hold pH steady.
Page 25: Behavior of Salts of Weak Conjugate Bases
Example: Cl^- does not react with H₂O!
Strong acids have weak conjugate bases:
Reactions:
For strong acids or bases: Will salts change the pH of water?
A: GO
B: NO GO
Page 26: Salts of Weak Acids and Bases
Example:
Weak acids with their conjugate bases can lead to basic solutions.
Page 27: Behavior Repeated for Conjugate Bases
Identical to above: Salt from weak acid or base will also affect water pH.
Page 28: Behavior of Weak Bases in Acids
Example reaction for NH₃ with water:
The salt $NH_4^{+}$ will lead to a solution acidic in nature.Kw = Ka \times KbKw = 1.0 \times 10^{-14}NH4Cl(s) → NH4^{+}(aq) + Cl^{-}(aq)NH4^{+} + H2O ⇌ NH3 + H3O^{+}
Relevant Constant: $K_b$ for ammonia = $1.8×10^{-5}$.
Page 32: Continuing pH Calculation for NH₄Cl
For $NH4^+$, $Ka = 5.6 × 10^{-10}$.
Page 33: Setting up Initial Conditions for Reaction with NH₄Cl
RICE Table Setup:
Initial:
$NH_4^+$ = 0.42 M
$NH_3$ = 0
$H_3O^+$ = 0
Page 34: Continuing RICE Table for Change
Reaction and changes should be established:
Change: NH_4^{+} o 0.42 - xNH₃ o +xH₃O^+ o +x$$
Page 35: Review of Equilibrium in RICE Table
Evaluate equilibrium change: $0.42 - x, x, x$.
Page 36: Assessing Assumptions
Assumption Check:
$0.42 M - 1.5 × 10^{-5} M ≈ 0.42 M$
Page 37: pH of Saline Solutions and Comparisons
Using solutions: $KX$, $KY$, and $KZ$.
Understand their pH levels (7, 9, and 11) as it connects to acid strength.
Page 38: Relating pH Values to Acid Strength
Identify strong acid and basic characteristics of $KY$ and $KZ$.
Page 39: Comparative Acid Strengths
Increase in pH value correlates to a decrease in acid strength.
Page 40: Problematic Salt Solutions
Example salts and their acidity/alkalinity when dissolved in water:
A. NH₄Cl
B. NaF
C. LiI
D. KNO₃
E. NaCH₃COO
Page 41:** Repeat Questions on Salty Acidity
Reiterative queries emphasizing salt combinations potency in acidic solutions.
Page 42: Confirmation of Acidic Solutions
Classifications again, identifying those turning acidic under solvation.
Page 43: Recognizing Key Salt Combinations
Follow-up questions regarding potential salt solutions turning acidic from aqueous solvent influence.
Page 44: Clear Acidic Solution Parameters
Another run through differing salt combinations leading to acidic behavior.
Page 45: Reiterating Acidic salts in Solutions
Rows of proposed acidic solutions through defined salts.
Page 46: Reaction of Acids and Bases with Salts
Example of interaction: $CH3COOH + H2O ⇌ CH_3COO^{-} + H₃O^+$
Acids and bases: Examine the reaction pathways.
Page 47: Effect of Salts in Acid Solution
Reaction descriptions reiterating salt formations leading to dissociation shares.
Page 48: Species in Weak Acid-Salt Solutions
Interaction models in solutions sharing presence of proton donors and base interactions.
Page 49: Buffer Solution Characteristics
Key Points:
A buffer solution resists pH change.
May consist of weak acid with conjoined conjugate basis or vice versa.
Highlight importance of components to counteract added H⁺ or OH⁻.
Page 50: Continued Characteristics of Buffers
Review same definitions but through differing reactive avenues for pH alterations.
Page 51: Identifying Buffer Solutions
Key Identifications:
Pairs containing weak acids and salts with conjugate bases.
Page 52: Identifying Weak Acids and Bases in Salts
Statements regarding utility of solid compounds to establish buffer capacity.
Page 53: Reactivity in Buffer Mixes
Responses: H³O⁺ presence noted from introduced acids and ways buffers can mitigate adjustments in pH influence from externalities.
Page 54: Buffering Capacity Indicators
Alert to mixtures’ sources sharing their base capacity to react attentively to acid inputs.
Page 55: Recognition of Buffer Reactions
Examples showcase successful recognition of weak bases buffer partnerships with salt components resulting in stability.
## Page 56: Buffer pH Value Comparisons
Chemical example: Discuss pH of clear concentrations of CH₃COOH isolated against buffer contributions with sodium acetate present.
Page 57: Repeat Analysis of Reactivity
Engage back to initial pH statements with presence of calculated conjugate elements.
Page 58: H⁺ Ion Concentration calculations
Utilize further equations for liquid reaction assumptions concentrating on weak acid behaviors vs. solvent ions.
Page 59: Components for reactions across CH₃COOH and NaCH₃COO
Concentration quantities highlight using reactive pairs against previous setups to determine pressure impact on ion positives or negatives.
Page 60: Comprehensive Reactions of Salt and Acidity
An example of sodium acetate indicates values expected amid potential calculations of solutions.
Page 61: Utilizing Volumes Effectively
Building with contributions from original compounds flowing through datasets managing equilibria following reactions.
Page 62: Assumptions for Promotable Phases
Assume integration through mixtures yields useful footing to measure anticipated behavior contributions across calculations.
Page 63: Assumptions Check with Weak Acids in Control
Guarded responses show methodical movements through fractional evaluations leading from vanishing acidic instances to stable supplies.
Page 64: Molarity and Prompted Acidity
Provide iterative analysis stopping amidst equilibrium setups contributing over buffer pH factors.
Page 65: Ending Calculations in Buffer Changes
Collating back initial focus through organized data shows useful methods pivoting from expanding ion sizes.
Page 66: Understanding Le Chatelier's Principle
Principle explains reactions shifts amid stress being the opposite of changes encountered leading to equilibrium correction.
Page 67: Example Scope absorbed
Various chemical reactions and resourcing their pH responses necessitating change.
Page 68: Buffers and Their Salt Compositions
Review formations across equal concentration compositions yielding effective mixing solutions.
Page 69: Determining Buffer Equilibrium Shifts
Analyzing if adding strong acids modifies systems and their expected pH outcomes.
Page 70: Titration Equivalence Points
Record pH conclusions tilting around equilibrium for acid bases engaging through volume measures.
Page 71: Structuring pH Inputs and Outputs
Distinguishing gradual levels of added solution management reflecting expected curve behaviors in titrations.
Page 72: Recognizing Midpoint Equivalence during Reactions.
Viable approach to connecting permanent interactions seen upon strict adherence amid reactive definitions.
Page 73: Strong Acid Examples
Introduced examples emphasizing strong acid elements through various chemical entities.
Page 74: Strong Bases Accompanying
Several references to strong bases reflecting reactive procedures through simple data outputs.
Page 75: Defining Buffer Pairs
Explain how combination pairs yield interactions across salutary mixture outputs.
Page 76: Additional Buffers Definition into Bases
Feedback on responsive indications relating across acid presence examples sharing significant buffer characterization.
Page 77: Confirmatory Le Chatelier's Reference
Reassurance on the basic tenets reiterating change responses involving equilibrium adjustments.
Page 78: Key Components of Effective Buffers
Quick hints at elements making up buffer solutions enhancing proportionality for purity.
Page 79: Evaluations across Buffer Capacity
Elicit constructive insights over how effective to resist pH inconsistencies within solutions.
Page 80: Henderson-Hasselbalch Equation for Buffers
General overview of how to employ equations systematically through pH projective outcomes following added ranges.
Page 81: Follow-up with Previous Calculations
Continue with the ratio analyses across sodium figures determining desirable equilibria solutions.
Page 82: Henderson-Hasselbalch Equation Breakdown
Specific equation breakdown summarizing the relationships within strong acid dissociations.
Page 83: Application of Henderson-Hasselbalch Solutions
Continues to drive on through inputs leading from connected views influencing outputs aligning across ratios.
Page 84: Utilize HH for Buffer Estimations
Show the interactions fluctuating through variables to forecast positives against multitudes.
Page 85: Strong Acid Base Network Calculations
Precursor analysis expected maximum efforts leading transitions proceeding from HCl reactors.
Page 86: Application through Results with HCl Addition
Delineating clear buffer ratios through effective molarities reporting outcomes under H⁺ while factoring appropriate buffer presence.
Page 87: Inputs within Buffer Specifications
Continued registration of assumption outputs staying connected with chemical processes.
Page 88: Overall Display of Alteration
Focus again leveraging outputs under reached standards incentivizing nuclear reductions to solvent concentrations.
Page 89: Buffer Reactions Adjustments as H⁺ is Fluctuated
Margin management displaying essential shifts while addressing integrals amongst fluctuating states.
Page 90: Assumptions within H⁺ Interacting Dynamics
Calculate from available observed listed ratios across structured references spawning chemical interactions.
Page 91: Dynamic Shifts Under Weak Acids
Buffer dynamics changes address movement through alterations leading measured shifts.
Page 92: Range Management on Molar Concentration Estimates
Under moles connect qualities’ responses viewed across deployments.
Page 93: Positive Outcomes Following Calculation Parameters
Outputs positioned amid overwatch remains fixated on contributions from calculations’ impacts.
Page 94: Inputs Solidified Following Calculations
Gain proactive states between molarity outputs paths as discussed while still reducing to obtaining measures.
Page 95: Buffer Inputs and Masked Reactions
Drive resolve presenting standards amended to forecast outputs from H₃O addition simplifying reciprocating analysis points.
Page 96: Titration Key Components
Essential equipment signifying watchfulness through titration protocols enhancing totality within practical objectives.
Page 97: Essentials of Acid-Base Titration Understandings
Foundational statements portraying effects stemming from equivalences noted.
Page 98: Acid and Base Titration Comparisons
Observe unique differences amid various titration techniques established across different reactions specified.
Page 99: Reemphasizing the Power of Weak Acids Definition
Depict integral pathways and identities closely matching strong acids and bases.
Page 100: Neutralization Queries with NaOH
Challenges raising awareness across sodium potency leading to complete checks through respective ratios
Page 101: Accompaniment Across Neutralized Solutions
Emphasize potential substances remaining present across ratios yielding direct molarity outputs undertaken.
Page 102: Finalizing Neutral Concentration from Equivalence
Focus back on balancing equations performing total equivalence reactions validating outcomes determined.
Page 103: H⁺ vs OH- in Comparative Titrations
Resolve savings communicating against ongoing checks confirming circles through chemical balances anchoring across sectors.
Page 104: Strong Acid/Strong Base Titration Insights
Analytical frameworks across sample titration types and their interpretable outputs through approaches conveyed.
Page 105: Clear Extrapolation of Results Across Neutral Outcomes
Incorporate utilitarian checkpoints necessary across enzymatic orders yielding valid titrations throughout
Page 106: Monitoring Methods Circulating Solutions in Reactions
Through iterative checks displaying live pH span monitoring processes bypassing localized variables invoked.
Page 107: Neutralization Constants Establishments
Bring forth clear references challenge logical equivalences directed along through effective traditional measures.
Page 108: Titration Midpoints Featured in Observations
Basic buffer specifications host meetings targeting steep endpoints noted visibly upon approached concentrations through recorded pH settings.
Page 109: Purpose of Visualizing Titration Midpoints
Giving clarity to speckled visualizations through echoed responses established.
Page 110: Culmination of Titration Stages
Capture mapping remains aligned toward colored transitions leading strong acid needless oversights witnessed.
Page 111: Final Observational Intercepted at Titration Endpoints
Movement through allowed evaluations results sustaining queries analyzing post-event thresholds projected.
Page 112: Endpoint Significations within Practical Bands
Using targeted iterations recognizing precise positions fostering depths across thresholds assuredly matched upon checking across results and signatures clearly defined.
Page 113: Indicator Choices in Titration Dynamics
Make decisive pH assorted tidbits available across recognized transition maps emphasizing credibility amid conditions remaining relevant.