ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid...

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ACIDS AND BASES

Transcript of ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid...

Page 1: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

ACIDS AND BASES

Page 2: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

Additional KEY TermsHydroxide Hydronium

• Outline the historical development of acid base theories.

Include: Arrhenius, Bronsted-Lowry, Lewis • Write balanced acid/base chemical equations.

Include: conjugate pairs, amphoteric

Page 3: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

· Taste sour · Burn when touching skin· Turn blue litmus red· Neutralize basic solutions· Corrosive to metals· Strong or weak electrolytes

ACIDS

BASES· Taste bitter · Feel slippery· Turn red litmus blue · Neutralize acidic solutions· Strong or weak electrolytes

You should already be aware of most of these properties…except the taste. Don’t eat stuff in the lab, please.

Page 4: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

1. Arrhenius Definition

Svante Arrhenius (1859 - 1927)

Acids • Yield hydrogen ions (H+) in aqueous solution

Bases • Yield hydroxide ions (OH-) in aqueous solution

H+ is also called a “proton” because a Hydrogen atom without its electron is just a proton (it has no neutrons)

Page 5: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

HCl (aq) → H+ (aq) + Cl–

(aq)

NaOH (aq) → Na+ (aq) + OH–

(aq)

Page 6: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

2. The Bronsted-Lowry Theory

Lowry

Bronsted

20 years later:

What about ammonia (NH3) Bronsted? It acts as a base, but doesn’t have OH-.

I guess we need I new definition for acid and base, Lowry!

Acids• proton (H+) donor

Base • proton (H+) acceptor

Page 7: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

Ammonia accepts a proton from water:

NH3 (g) + H2O(l) NH4+

(aq) + OH-(aq)

H+

acceptor

Base is a proton (H+) acceptor:

donor

Follow the Hydrogen ion – who donated it, who accepted it.

Page 8: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

H3O+ ion called the hydronium ion

H+

acceptordonor

Acids is a proton (H+) donor:

Hydrochloric acid donates a proton to water:

HCl(g) + H2O(l)

H+ H2O

H3O+(aq)

H3O+ splits apart quickly, so H3O+ and H+ are written interchangeably.

+ Cl-(aq)

Page 9: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

Amphoteric: a substance which can act as either an acid or a base.

Water is amphoteric.Bicarbonate ion is also amphoteric.

HCO3- + OH- CO3

2- + H2OH+

acceptordonor

HCO3-

+ H2O H2CO3 + OH-

H+

acceptor donor

Page 10: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

Transition metal ions with charges of 2+ or 3+, create an acidic solution with water.

Step 1: Formation of a hydrate.

Water’s electrons are attracted to the BIG positive charge on Fe

Page 11: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

Step 2: Loss of H+ making acidic solution.

Fe(H2O)63+ + H2O H3O

+ + Fe(H2O)5(OH)2+ H+

H

All electrons are attracted inwards, so Hydrogen ion has

nothing to lose and leaves

Page 12: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

Acids Base • electron acceptor ● electron donor

3. Gilbert Lewis Definition

CH3COO-(aq) + H2O(l) OH-

(aq) + CH3COOH (aq)

H+

base acidWhat about those metals? I think we need a broader

definition?

Negative ions have extra electrons to donate to the lonely

H+

Page 13: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

Conjugate acid is what remains after a base has accepted a proton.

Conjugate base is what remains after the acid has donated its proton.

NH3 (g) + H2O(l)

base acid

NH4+

(aq) + OH-(aq)

Con. baseCon. acid

You are looking at the forward and reverse reactions – which compound donates for which direction?

Page 14: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

B + H2Obase acid

BH+ + OH-

Con. baseCon. acid

Each is called a conjugate pair.

HA + H2Obaseacid

H3O+ + A-

Con. baseCon. acid

These are generic equations for an acid or base reaction

Page 15: ACIDS AND BASES. Additional KEY Terms HydroxideHydronium Outline the historical development of acid base theories. Include: Arrhenius, Bronsted-Lowry,

Additional KEY TermsHydroxide Hydronium

CAN YOU / HAVE YOU?

• Outline the historical development of acid base theories.

Include: Arrhenius, Bronsted-Lowry, Lewis • Write balanced acid/base chemical equations.

Include: conjugate pairs, amphoteric