Acids & Bases

acid dissociation constant / acidity constant / acid-ionization constant

(Ka) a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction known as dissociation in the context of acid-base reactions.

Dissociate

(with reference to a molecule) to split into separate smaller atoms, ions, or molecules, especially reversibly

dilute

.make (a liquid) thinner or weaker by adding water or another solvent to it.

7

A pH of ___ is neutral

Salt + hydrogen (hydrogen gas)

Acid + metal

Salt + water + carbon dioxide

Acid + metal-carbonate

Salt & water (products) ●A salt is any ionic compound formed by a neutralization reaction ●Water comes from the combination of the hydrogen ions and the hydroxide ions HCl + NaOH --> NaCl + H2O

Base + acid (reactants) =

By definition, acids are those that produce the hydrogen ion when dissolved in water (H+) while bases produce the hydroxide ion (OH-). These ions, when in water, act as charge carriers and can hence conduct electricity. ---------------------------------------------------------------------------- Electricity can be conducted through a material if one of two things happen: Either electrons can be made to move or ions can be made to move. Electrons move around in a metal, in which the delocalized bonding allows them to flow freely around. In an electrolyte solution, there are ions in solution that can be induced to move around with applied voltage. In both cases, charge moves around, allowing conductivity. When an acid dissociates in water, you see the general equation: HA → H+ + A− Where H is the hydrogen given off by the acid and A- is the anion. Because there are ions present when the acid dissociates, acid solutions conduct electricity. ---------------------------------------------------------------------------- Conductivity arises only from the prescence of ions in the solution ---------------------------------------------------------------------------- When ionic compound dissolves, its positive and negative ions break free from the bond. These opposite ions are able to carry the charge and conduct electricity. This type of ionic compound is also known as an electrolyte. In different conducting media, different particles serve to carry charge: In metals, the charge carriers are electrons. ... In electrolytes, such as salt water, the charge carriers are ions, which are atoms or molecules that have gained or lost electrons so they are electrically charged.

Do acids/bases conduct electricity? If yes, why, how?

- React with many oils and fats - do not react with metals or carbonates.

Do bases react with metals / carbonates?

Salt conducts electricity in an aqueous estate but not in a solid state - when sodium chloride dissolves in water, the water separates the sodium and chlorine ions. It become an electrolyte solution as the sodium ions will conduct electricity once it has been separated from its chlorine ion partner.

Does salt conduct electricity

●Acids in food such as: vinegar (acetic acid), soda water (carbonic acid) lemon juice (citric acid) [are weak acids.] ●Hydrochloric Acid - HCl ●Nitric Acid - HNO3 ●Sulfuric Acid - H2SO4

Examples of acids

●Sodium Hydroxide - NaOH ●Potassium Hydroxide - KOH ●Calcium Hydroxide - Ca(OH)2 ●Magnesium Hydroxide -- Mg(OH)2

Examples of bases

Bronsted-Lowry

From idea conductivity, he came up definition acid and base

water could donate hydrogen ion, which classifies it as an acid using the Brønsted concept. Water can also accept hydrogen ion.

How can water ACT AS acid or base?

Sour (vinegar)

How do acids taste

Bitter (baking soda)

How do bases taste

less concen. (of products), higher pH #.

How would a picture/graph change for more dilute strong acid solution? How would pH change?

a large dissociation constant

If acids have this, they dissociate completely in water.

Although it is called a neutralization reaction, the resulting solution is not always neutral (pH of 7) - It depends on the strength of the acid and the base that are combined.

Is the resulting solution from a reaction of an acid and a base always neutral? Why?

1. an Arrhenius acid increases the concen. of hydrogen ions in an aqueous solution, while Arrhenius base increases the concen. of hydroxide ions 2. Arrhenius definitions of acidity and alkalinity restricted to aqueous solutions 3. in Arrhenius acid-base reactions, reaction between acid & base is a neutralization reaction.

Key points of Arrhenius definitions

● HCl - Hydrochloric Acid ● HBr - Hydrobromic Acid ● HI - Hydroiodic Acid ● HNO3 - Nitric Acid ● HClO4 - Perchloric Acid ● H2SO4 - Sulfuric Acid

Name and formula the 6 strong acids

● LiOH - Lithium Hydroxide ● NaOH - Sodium Hydroxide ● KOH - Potassium Hydroxide ● Ca(OH)2 - Calcium Hydroxide ● Sr(OH)2 - Strontium Hydroxide ● Ba(OH)2 - Barium Hydroxide

Name and formula the 6 strong bases

is colorless below pH 8.5, but turns red above pH 9.0.

On the pH scale, when is a substance colorless or pink/red with phenolphthalein

Hydronium ion donated. Proton = H+

Proton donated =

Neutral

Substance that's neither acidic or basic is...

Substance that dissociates in water to form hydroxide ions

Svante Arrhenius definition of Base

Substance that dissociates in water to form hydrogen ions

Svante Arrhenius definition of acid

The warmer the color (oranger, redder, dark red)

The more acidic the substance, what's the color like

The cooler the color (greener, bluer, dark blue)

The more basic the substance, what's the color like

Svante Arrhenius

The other guy who came up with defs. for base and acid. Swedish, came before bronsted-lowry

neutralization reaction

The reaction between an acid and a base is called a...

always true strong acids concen.s (molecules) decrease w/ water, at one point there will be no molecules left.

True/False?: strong acids completely dissociate in water

sometimes true strong acids can have lower pH than weak acids if they're more dilute strong acids and are less acidic. But there can also be stronger weak acids, that can have higher pH than more dilute strong acids, so not always case that stronger acids have lower pH's.

True/False?: strong acids have lower pH's than weak acids

''Joined together" - compound formed by the joining of two or more chem. compounds - conjugate acid = a species formed by the reception of a proton (H+) by a base—in other words, it is a base with a hydrogen ion added to it. ... Acid + Base ⇌ Conjugate Base + Conjugate Acid. Acid lose H+ --> conjugate base Base gains H+ --> conjugate acids. . ----------------------------------------------------------------- HA --> H+ + A-, where HA is the acid, H+ is the hydrogen ion, and A- is the conjugate base of the acid (the result after it give H+, after H+ gone). Conjugate base - substance produced after an acid donated its proton Conjugate acid - substance formed when a base accepts a proton Conjugate acid can donate proton to conjugate base to reform original reactants in the reverse reaction

What are conjugates? Conjugate base? Conjugate acid?

Color turns pink

What color results when the indicator phenolphthalein is added to a base

Colorless

What color results when the indicator phenolphthalein is added to an acid

Turns it red

What do acids do to blue litmus paper

Stays red

What do acids do to red litmus paper

Stays blue

What do bases do to blue litmus paper

Turn it blue

What do bases do to red litmus paper

- Strong acids & bases dissociate completely in water --> produce more of the ions that conduct electricity - Strong conductivity results when dissociation is nearly complete - weak acids & bases dissociate slowly when dissolved in water

What has stronger conductivity, weak or strong acids? Weak or strong bases? Why?

Frequently burns nose

What smell do acids have

Usually no smell (except NH3)

What smell do bases have

watery

What texture do acids have

slimey or slippery

What texture do bases have?

Unlike Arrhenius, Bronsted-Lowry don't assume substance always in water. Not always the case.

What's main diff. Arrhenius and Bronsted-Lowry definitions

Salt: grainy, hard Water: slippery?

acids and bases both: Feel

Salty

acids and bases both: Taste

the hydrogen ion (H+) = proton

When dissolved in water, what ion do acids produce

The hydroxide ion (OH-)

When dissolved in water, what ion do bases produce

When it reacts with an acid

When does an amphiprotic molecule/ion act as a base?

the concentration of hydrogen ions is high.

When pH is low...

Shorthand [H3O+] (hydronium)

[H+] symbol meaning

Acid

a chem. substance that neutralizes alkalis, dissolves some metals, and turns litmus red; typically, a corrosive or sour-tasting liquid of this kind.

anything that donates a proton

acid, from Bronsted-Lowry definition

No color change

acids and bases both: Color from indicator litmus

Pretty much colorless

acids and bases both: Color from indicator phenolphthalein

Yes they could - Salt conducts electricity in aqueous state - some water has ions

acids and bases both: do they conduct electricity? Explain.

Yes

acids and bases both: do they react with metals?

- H2O - sodium chloride - ammonium dichlorate - magnesium sulfate - sodium bicarbonate

acids and bases both: examples

Metals & carbonates - Frequently react with metals to form H2 - Carbonate ions (CO32-) have a negative charge and when acids react with them CO2 produced

acids react with...

Conduct

allows electricity/heat to travel along or through it

strong acid

an acid that completely dissociates in water.

anything that accepts a proton

base from Bronsted-Lowry definition

1. strong acid reactions not reversible 2. as a result, strong acids only made of products while weak ons made of both (in fact, less product than reactant as it seems)

difference between strong acids and weak acids

when weak acid stronger it has smaller pH #, when strong acid solution more dilute it has bigger pH #. Their pH #s can come to a point where they are the same.

how can weak acid solution have same pH as strong acid solution?

it would have higher concen. (of reactants & products), pH # smaller.

how would a picture/graph change for stronger weak acid solution? How would pH change?

there be less H3O & A and more HA, would have higher pH # than strong acids pH

in a drawing, reactant HA = 0 and products A = 20, H3O+ = 19 (HA + H2O = A + H3O--> A + H3O) How would picture/graph change for weaker acid solution? How would its pH change?

In Arrhenius, an acid's definition is limited to cases in which water is a solvent (substances always assumed to be in water) In B.L., substances aren't always assumed to be in water Arrhenius says base is substance that when dissociated in water produces [OH-] ions (NaOH + H2O --> NaOH2+ OH-) B.L. says base is substance that accepts proton. (HCl + NH3 --> NH4+ + Cl-) Arrhenius says acid is substance that releases proton in water (produces H+ ions) (HCl + H2O --> H+ + Cl-) B.L. says acid is substance that donates proton. (HCl + NH3 --> Cl- + NH4+)

major differences between acid & base defined by Arrhenius Theory and Bronsted-Lowry Theory

amphiprotic/amphoteric molecule/ion

molecules/ions that can act as acid or base - can react as acid or base

- How acidic or basic a substance is - the concentration of Hydrogen Ions in a solution

pH scale measures...

0-14

pH scale ranges from ___ to ___

Base

substances that, in aqueous solution, are slippery to the touch, taste astringent, change the color of indicators (e.g., turn red litmus paper blue), react with acids to form salts, promote certain chemical reactions (base catalysis), accept protons from any proton donor, and/or contain completely or partially displaceable OH− ions. Examples of bases are the hydroxides of the alkali metals and alkaline earth metals (NaOH, Ca(OH)2, etc.). Ex: baking soda, soap, drain cleaner