L07 Chem 151 Lecture Notes - Lecture 5: Litmus, Polyatomic Ion, Conjugate Acid

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harlequinimpala978

13 Dec 2016

School

WUSTL

Department

University College - Chemistry

Course

L07 Chem 151

Professor

Redden

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28 September 2015

Lecture 5

I. Properties of Acids and Bases

A. Brønstead-Lowry Acid and Bases Diagram

Acids

Bases

General Properties

• Change litmus paper to red

• React with carbonates to form CO2

• React with active metals (that are

electropositive) to form H2 gas

• Change litmus paper to blue

• React with many metal ions to form

precipitates

Arrhenius Definition

A substance, that when dissolved in

H2O, increases the concentration of

hydrogen (hydronium) ions in the

solution

A substance, that when dissolved in H2O,

increases the concentration of hydroxide

ions (OH-) in solution

Neutralization

An Arrhenius acid reactions with an Arrhenius base to form a salt in which the cation

comes from the base and the anion comes from the acid

Brønstead-Lowry

Definition

An acid is a substance that can donate a

proton to another substance

A base is a substance that can accept a

proton from another substance

Lewis Definition

(broadest definition)

An acid is an electron pair acceptor

A base is an electron pair donor

Basic Formulas

• HnA: A-N is a simple anion (forming

binary acids, such as in HCl, H2S,

HCN, and HI) or a polyatomic anion

(forming oxoacids, such asH2SO4,

HNO3, HCLO)

• -COOH: organic acids (such as

CH3COOH and C6H5COOH)

• M(OH)m: Mm+ is a metal cation (such

as KOH and Ca(OH)2)

• R3N: Ammonia or an organic amine

where R can be H or an alkyl group (-

CH3, -CH2CH3, etc.)

Anhydrides

Nonmetal oxides are acid anhydrides:

• SO3 + H2O -> H2SO4

• CO2 + H2O -> H2CO3

• P2O5 + H2O -> H3PO4

Metal oxides are base anhydrides:

• Na2O + H2O -> 2NaOH

• Li2O + H2O -> 2LiOH

• CaO + H2O -> Ca(OH)2

Strong

Strong acids completely dissociate in

water and are strong electrolytes:

HCl, HBr, HI, HClO3, HClO4, H2SO4,

HNO3

Strong bases completely dissociate in water

and are strong electrolytes:

Any group one or two metal hydroxides are

strong bases

Weak

Weak acids only partially dissociate in

water and are weak electrolytes:

organic acids, oxoacids with fewer

oxygens, etc.

Weak bases only partially dissociate in

water:

Ie- NH4OH <---> NH4+ + OH-

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Document Summary

Acids: change litmus paper to red, react with carbonates to form co2, react with active metals (that are electropositive) to form h2 gas. H2o, increases the concentration of hydrogen (hydronium) ions in the solution. Bases: change litmus paper to blue, react with many metal ions to form precipitates. A substance, that when dissolved in h2o, increases the concentration of hydroxide ions (oh-) in solution. An arrhenius acid reactions with an arrhenius base to form a salt in which the cation comes from the base and the anion comes from the acid. An acid is a substance that can donate a. A base is a substance that can accept a. An acid is an electron pair acceptor proton from another substance. A base is an electron pair donor (broadest definition) Basic formulas: hna: a-n is a simple anion (forming, m(oh)m: mm+ is a metal cation (such binary acids, such as in hcl, h2s,

Related Questions

need help with 1 through 4

QUESTION 1

Which of the following substances is most acidic?

		Cowâs milk - pH 6.6
		Apple juice - pH 3.0
		Tomato juice - pH 4.5
		Distilled water - pH 7.0

2 points

QUESTION 2

A buffer is a substance that converts:

Alkaline solutions to neutral solutions.

Acidic solutions to alkaline solutions.

Strong bases or acids to weak bases or acids.

Acidic solutions to neutral solutions.

QUESTION 3

How does a solution of pH 7 compare to a solution of pH 10?

		pH 7 has more OH^- ions
		pH 7 is more basic
		pH 7 has a higher pH
		pH 7 has more H⁺ ions

2 points

QUESTION 4

According to the Arrhenius Theory of acids and bases, a base is:

A substance that decrease the amount of hydroxide ions present.

A substance that increases the amount of hydroxide ions present when it is dissolved in water.

A substance that increase the amount of hydrogen ions present.

A substance that increases the amount of hydrogen ions present when it is dissolved in water.

QUESTION 5

Which of the following are true regarding acid-base titrations?

		They are used to determine the concentration of an unknown acid or base.
		The acid or the base must be a standard solution with a known concentration
		The standard solution is titrated into the chemical with the unknown concentration.
		All of the above are true regarding acid-base titrations.

2 points

QUESTION 6

Which of the following is not an example of a neutralization reaction?

HCl + NaOH NaCl +H₂O

2 NaOH + H₂CO₃ Na₂CO₃ +2 H₂O

H₂SO₄ + 2 NH₄OH (NH₄)₂SO₄ + 2 H₂O

2 AgNO₃ + Zn 2Ag +Zn(NO₃)₂

QUESTION 7

Which acid base theory defines an acid as a proton donor and a base as a proton acceptor?

		Arrhenius Theory
		Bronsted-Lowery Theory
		Conjugate Pairs Theory
		Lewis Theory

2 points

QUESTION 8

The Arrhenius Theory states that acid-base reactions create a solution composed of a water and a salt. This is because mixing an acidic and basic solution together yields:

A neutral solution

A solution with a pH at or near 7

Both A and B are correct

QUESTION 9

Which of the following correctly defines a standard solution?

		A solution which always has the same molecular geometry.
		A solution in which the concentration is precisely known.
		A solution in which the volume is precisely known.
		A solution which always has different levels of solutes and solvents.

2 points

QUESTION 10

Acids naturally present in food are generally safe to eat because they are usually:

		Concentrated
		Dilute
		Weak
		Strong

None of the above are correct

L07 Chem 151 Lecture Notes - Lecture 5: Litmus, Polyatomic Ion, Conjugate Acid

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