Acids and Bases (Intro to pH)

Chem catalyst

List three examples of solutions.

For each, tell us what the solute is and
what the solvent is.

Chem Catalyst

1. Calculate the molarity of a solution

that has .500 moles of H+ in 2.5 L.

2. What is the molarity of a solution that

has 45.0 grams of NaCl dissolved in
400 mL?

Acids & Bases

They are everywhere!

​Why are some solutions different pHs?

​In any solution, the product of the hydrogen ion, H+, concentration and hydroxide ion, OH–, concentration is a constant.

What is an acid?

▪ An acid is a solution that has an excess

of Hydrogen (H+ ions). They DONATE H+ ions

example HBr: hydrobromic acid

▪ Weak organic acids look a little

different and are molecules which
contain a -COOH, yet these also have an
excess of H+ ions

example acetic acid: CH3COOH

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Acids are substances that have ​

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​ of ​

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Acids ​

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H⁺ ions.

Three famous strong

acids

Strong Acids Ionize 100% in aqueous solution so they
are strong electrolytes and conduct electricity when
they are dissolved in water!
Hydrochloric Acid
(HCl) HCl (aq) → H+

(aq) + Cl-(aq)

Nitric Acid
(HNO3) HNO3(aq) → H+

(aq) + NO3

-(aq)

Sulfuric Acid (battery acid)
(H2SO4) H2SO4(aq) → H+

(aq) + HSO4

-1(aq)

Acetic acid is a famous weak acid!

Properties of an Acid

▪ Tastes Sour
▪ Conducts Electricity
▪ Corrosive; (they break

down certain substances.
Many acids can corrode
fabric, skin,and paper).

▪ Some acids react

strongly with metals.

▪ Turns blue litmus

paper red

Uses of Acids

▪Acetic Acid = Vinegar

▪Citric Acid = lemons, limes,
& oranges. It is in many
sour candies such as
lemonhead & sour patch.

▪Ascorbic acid = Vitamin C
which your body needs to
function.

▪Sulfuric acid is used in the
production of fertilizers,
steel, paints, and plastics.

▪Car batteries

What is a base?

▪ A strong base is a solution

that has an excess of OH-
ions.

▪ Bases are also defined

as substances that can
accept hydrogen ions
from an acid

▪ H+ + OH-→ H2O

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Bases are substances that have ​

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​ of ​

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Bases ​

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H⁺ ions.

Three famous strong

bases

Strong Bases Ionize 100% in aqueous solution so they
are strong electrolytes and conduct electricity when
they are dissolved in water!

Lye: NaOH is a strong base that ionizes 100% in
water

Lime: Ca(OH)2

Magnesia: Mg(OH)2

Ammonia is a famous
weak base

Weak Bases Ionize 1% of less in aqueous solution so
they are weak electrolytes and barely conduct
electricity

NH3 (aq) + H+OH - → NH4

+

(aq) + OH-

(aq)

*notice that NH3 accepts the hydrogen ion
from water to leave behind the OH-. So
ammonia is still considered a base

Properties of a Base

▪Feel Slippery

▪Taste Bitter

▪Corrosive (burn skin, tissue)

▪Can conduct electricity.
(Think alkaline batteries.)

▪Do not react with metals.

▪ Turns red litmus

paper blue.

Have You Used Bases Before?

▪ Bases give soaps,

ammonia, and many other
cleaning products

▪ The OH- ions interact

strongly with certain
substances, such as dirt
and grease.

▪ Chalk and oven cleaner are

examples of familiar
products that contain
bases.

▪ Your blood is a basic

solution.

Video to 12:37 pH scale

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Acid or Base?

Hydrogen iodide (HI)​

Select answer

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Acid or Base?

Hydrogen flouride (HF)​

Select answer

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Acid or Base?

Strontium hydroxide Sr(OH)₂ ​

Select answer

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Acid or Base?

Carbonate ion (CO₃^2-) ​

Select answer

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Acid or Base?

Formic Acid (HCOOH) ​

Select answer

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Acid or Base?

Lye (NaOH) ​

Select answer

pH Scale preview!!!

▪pHis a measure of how acidic or basic a
solution is.

•The pH scale ranges from 0 to 14.

▪Acidic solutions have pH valuesbelow 7

▪A solution with a pH of 0 is very acidic.

▪A solution with a pH of 7 is neutral.

•Pure water has a pH of 7.

•Basic solutions have pH values above 7.

pH Scale

• A change of 1 pH unit represents a

tenfold change in the acidity of the
solution. (X 10)

• For example, if one solution has a pH of 1

and a second solution has a pH of 2, the
first solution is not twice as acidic as the
second—it is ten times more acidic.

How to Calculate pH and pOH

Key patterns

1.The sum of the two exponents (in the row) always equal 14.

•  pH  +  pOH  =  14

2. The pH in the third column equals the absolute value of the exponent of the H+ concentration.

Multiple Choice

If the H+ concentration of a solution is 1.0 x 10^-5, what is the OH- concentration?

• 1.0 X 10^-5

• 1.0 X 10^-1

• 1.0 X 10^-19

• 1.0 X 10^-9

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If the concentration of H+ in a solution is 1.0 x 10^-6, what is the overall pH value?​

Select answer

Acid – Base Reactions

▪A reaction between an
acid and a base is
called neutralization.
An acid-base mixture
is not as acidic or
basic as the individual
starting solutions.

Open Ended

How did you demonstrate this neutralization last class? EXPLAIN.

Acid – Base reactions

Each salt listed in this table can be formed by the reaction between an acid and a base.