1#Biochemistry unit first semester second for nurses students

BASIC CONCEPTS
OF CHEMISTRY
Dr. Muhammad Nabi
Doctor of Pharmacy,
M. Phil Biochemistry
M. Phil Pharmacology,
Ph. D Pharmacology

Outlines
 Basic concepts of Chemistry
1. Importance of Chemistry in nursing
2. Matter
3. Elements Mixtures & Compound
4. Structure of Atom (Periodic Table)
5. Chemical formula
6. Chemical Reactions
7. Equations
8. Bonding
9. Redox Reaction
10. Acid Base

What is Nursing?
Nursing is a healthcare profession focused on the care of
individuals, families and communities so they may attain,
maintain, or recover optimal health and quality of life from
conception to death.
(From Wikipedia)

Why is Chemistry Important to Nursing?
A nurse should have basic knowledge of all the processes
that occur at the cellular level, e.g.
 actions of enzymes
 diffusion across cell membranes
 oxygen transport
 How pH of the blood is balanced
 glucose metabolism
 what goes wrong in patients with diabetes?
All these questions and many, many more all need a good
understanding of the basic concepts of chemistry.

Continued
 Your patient might have acidosis or alkalosis which may
be metabolic or respiratory in nature or both.
 you also need an understanding about electrolytes ( Na,
K, Ca etc).
 The nurse will be handling so many different fluids and
if he/she does not know what it is for, and how it will
affect the patient, the patients life will be in danger.

Continued
 You need to know the language of chemistry.
 If someone says that substace X is in millimoles, you
must know what it means.
 You must know how to prepare 5% solution of a
medicine etc.

Continued
 Also, you need to have a basic understanding of the
difference between a base and an acid
 It will also help you understand how it is that some
medications are more readily absorbed than others in
the body.
 pH is a concept that comes up in urinalysis, blood work
and blood gasses.

 Nurses must understand how particular medicines will react in different
patients. This helps to avoid wrong combinations of drugs that can lead to
adverse effects.
 Your patient is feeling giddy. If you don’t know chemistry you will not be
able to treat that.
 Your patient is vomiting and you don’t know chemistry then you cannot
treat him.
 Your patient have ingested a toxic chemical. If you don’t know the
formula of that chemical and its anti toxin then you are not able to treat
him.

1#Biochemistry unit first semester second for nurses students

2.Matter
Matter is everything around . Atoms and molecules are all
composed of matter. Matter is anything that has mass and takes up
space.
Matter can be classified on the basis of chemical and physical
properties. On the basis of physical properties matter can be
classified into solids, liquids and gasses. And on the basis of
chemical properties matter is classified as elements, mixtures and
compounds. We will study about the classification of matter on the
basis of physical properties.

States of Matter
Copied from: http://media-2.web.britannica.com/eb-media/65/63065-004-07B69F7B.jpg
Date: October 7, 2015

Characteristics of Matter
• Particles of matter have spaces between them
• Particles of matter are constantly moving
• Particles of matter attract each other.

States of matter
On the basis of physical states, all the matter
can be classified into three groups: Solids,
Liquids and Gasses. For example:
i) Sugar, Sand, Iron, Wood, Rocks etc.
ii) Water, Milk, Petrol, kerosene etc.
iii) Air, Oxygen, Steam etc.

Properties Of
Solids
The solids have the following characteristic properties:
• Have a fixed shape and a fixed volume.
• Cannot be compressed much.
• Have high density.

Properties Of
Liquids
The liquids have following characteristics properties:
• Have no fixed shape .
• Cannot be compressed.
• Generally flow easily.

Properties Of
Gasses
The gasses have following characteristics properties:
• Have neither a fixed shape nor fixed volume.
• Gasses have very low density.
• Can be compressed easily.

1. Spaces between the particles . Spaces between the particles is
minimum in solids, maximum in gasses and intermediate in
liquids.
2.The force of attraction between particles. The forces of
attraction between the particles are the strongest in solids ,
less strong in liquids and negligible in gasses.
3. The amount of particles. The movement of particles is the
minimum in solids, intermediate in liquid an maximum in
gasses

3.Elements
An element is a pure substance that cannot be
separated into simpler substances by physical
or chemical means

Characteristic Properties
▫ Physical Properties
Boiling Point
Melting Point
Density
▫ Chemical Properties
Reactivity with different substances

Can you use: density, conductivity, reactivity,
melting point to identify each element?

Elements are grouped into categories
based on the properties they share
 Example: Iron, nickel, and cobalt are all shiny and conduct
heat and electrical current. They’ve been placed into a
large group called metals with similar elements. If you know
the category, you know the properties.

Elements
Metals Nonmetals Metalloids
are divided into

Major Categories of Elements
1. Metals: shiny, good conductors of
thermal energy and electric current,
malleable (can be hammered into
thing sheets) and ductile (can be
drawn into thin wires)
Elements in this category
Iron, Tin, Lead, Copper

2. Nonmetals: dull, poor conductors of
thermal energy and electric current,
brittle and unmalleable
Elements in this category
Neon, Bromine, Sulfur

3. Metalloids: have properties of
both metals and nonmetals,
some are shiny while others are
dull, some are good conductors
while others are not
Elements in this category
Silicon, Antimony, Boron

Compounds
▫ Pure substance composed of two or
more elements that are chemically
combined.
▫ In order for elements to combine, they
must react, or undergo a chemical
change, with one another.

Familiar Compounds
▫ Table Salt: Sodium and Chlorine
▫ Water: Hydrogen and Oxygen
▫ Sugar: Carbon, Hydrogen, and Oxygen
▫ Carbon Dioxide: Carbon and Oxygen
▫ Baking Soda: Sodium, Hydrogen, Carbon,
and Oxygen

Compounds Have
Unique Sets of Properties
▫ Physical properties
▫ Chemical properties
▫ Compounds have different
properties from the elements that
form it.
Ex: Table salt is made of sodium (which
reacts violently with water) and
chlorine (which is poisonous).

Compounds Can Be
Broken Down into Simpler Substances
▫ Either broken down into
elements through chemical
changes…

▫ Or undergo chemical changes and
form simpler compounds

Compounds Cannot Be
Broken Down by Physical Changes
▫ Only way to break down a compound
is through a CHEMICAL change.

Mixture: combination of two or more
substances that are not chemically
combined
Two or more materials form a mixture if
they do not react to form a compound

Substance in a mixture keep their
identities.
Mixtures can be physically separated.

Solutions
▫ Solution: mixture that appears to be a
single substance but is composed of
particles of two or more substances that
are distributed evenly amongst each
other
▫ Also described as a
homogenous mixture

▫ Process in which particles separate
and spread evenly throughout a
mixture is known as dissolving.
▫ The solute is the substance that
is dissolved, and the solvent is
the substance in which the solute
is dissolved.

Salt water
Solute: Salt
Solvent:Water

Examples of Different
States in Solutions
Gas in gas Dry air (oxygen in nitrogen)
Gas in liquid Soft drinks (carbon dioxide in water)
Liquid in liquid Antifreeze (alcohol in water)
Solid in liquid Salt water (salt in water)
Solid in solid Brass (zinc in copper)

 Particles in solutions are so small that they never settle out,
nor can they be filtered out, and they don’t scatter or block
light.

Concentration:
How much solute is dissolved?
▫ Concentration: measure of the amount of
solute dissolved in a solvent
▫ Knowing the exact concentration of a
solution is very important in chemistry
and medicine because using the wrong
concentration can be dangerous.

Suspensions
▫ Mixture in which particles of a material
are dispersed throughout a liquid or gas
but are large enough that they settle
out.
▫ A suspension can be separated
by passing it through a filter

Application
▫ Many medicines, such as remedies for
upset stomachs, are suspensions.
The directions on the label instruct you
to shake the bottle well before use.
▫ Why must you shake the bottle?
▫ What problem could arise if you don’t?

Biology Connection
▫ Blood is a suspension. The
suspended particles, mainly red blood
cells, white blood cells, and platelets,
are actually suspended in a solution
called plasma. Plasma is 90% water
and 10% dissolved solutes including
sugar, vitamins, and proteins.

S T R U C T U R E O F A N
ATO M
CHEMISTRY GROUP WORK

INTRODUCTION
Atom was discovered by John Dalton. He
proposed the famous atomic theory in
1807. Atoms are fundamental unit of
matter. The existence of different kinds of
matter is due to different atoms constituting
them.

A major challenge before the scientists at the
end of the 19th century was to reveal the
structure of the atom as well as to explain its
important properties. Many scientists worked
hard and proposed many models for the
atom, here we are going to learn about the
structure of an atom

What is in the structure of an
atom?
• Nucleus - center of the atom
Home of Protons and Neutrons
Has a positive charge
• Proton
Has a relative mass of 1u
Has a positive (+) charge
Determines the atomic number
Found inside the nucleus

What is in the structure of an
atom?
• Neutron
Has no (0) charge
Has a relative mass of 1u
Found inside the nucleus

Structure of an atom
• Electron
Has a negative (-) charge
Found outside the nucleus
• Rutherford atom model - electrons are
around the nucleus
• Bohr model – electrons are in specific
energy levels called shells

How are p, n, e
related?
• No. protons = No. electrons
• No. protons = atomic number
• No. protons + No.neutrons = mass number
• No. neutrons=mass no. - atomic no.

• The outermost shell of an atom is known as its
valence shell.
• The electrons present in the outermost shell
of an atom are known as the valence electrons
• The Valency of an element may be defined as
the combining capacity of its atoms with
atoms of other elements in order to acquire
octet configuration.
• For eg; The valency of hydrogen is 1.

• The number of protons in an atom is referred
to as its Atomic Number.
• It is denoted by the letter ‘ Z ’.
• Elements are defined by the number of
protons they posses.
• The atomic number of hydrogen is 1.

• The mass of an atom resides in its nucleus.
The mass of an atom is practically due to
protons and neutrons alone.
• Therefore, Mass Number of an atom is the
sum of neutrons and protons present in the
nucleus of an atom
• for hydrogen, its mass number is 1u.

• Isotopes are atoms of same element, which
have different mass numbers but same atomic
number.
• Their chemical properties are similar but
physical properties are different.

• An isotope of uranium is used as a fuel in
nuclear reactors.
• An isotopes of cobalt is used in the treatment
of cancer.
• An isotope of iodine is used in the treatment
of goitre.

• Atoms of different elements with different
atomic numbers ,which have the same mass
number are known as isobars.
• Examples of isobars are: calcium(z=20)and
argon(z=18).their mass number is 40 u.

Dictionary:
The chemical formula of a molecule shows the number
of atoms of each element in the molecule.
Formula consists of the symbols for the elements that
make up the molecule, each followed by a number.

Example
soxygen molecule contains 2 atoms O2
bromine molecule contains 2 atoms Br2
nitrogen molecule contains 2 atoms N2
If the formula contains only one atom of a particular type,
there is no need to put in ‘1’.

Exercise:
 Draw a target diagram for the following covalent compounds
 Draw a diagram of the molecule using lines to represent the covalent
bonds
 Write the formula for each compound under the target diagram
9. Hydrogen fluoride
10. Carbon
chloride
11. Phosphorus hydride
12. Sulphur
oxide
HF
CCl4
PH3
SO

Valencies can be used to work out formula.
Step 1: Write down the symbols for the elements present
e.g. calcium cholride
Ca Cl
Step 2: write the valencies of the elements
present above each symbol
2 1
Ca Cl

Step 3: Cross over the valencies
Ca Cl
2 1
Ca1Cl2
Step 4: if there are any common factors cancel them
out and omit any ‘1’ present
The formula of calcium chloride is: CaCl2

What about silicon oxide:
Step 1: Write down the symbols for the elements
present Si O
Step 2: write the valencies of the
elements present above each symbol
Si O
4 2

Step 3: Cross over the valencies
4 2
Si O
Si2O4
Step 4: if there are any common factors cancel them
out and omit any ‘1’ present
In this case both factors can be divided by 2.

Examples
:
•Phosphorus chloride
•Boron sulphide
•Silicon fluoride
•Sulphur chloride
•Phosphorus iodide
•Iodine bromide
•Boron chloride
PCl3
B2S3
SiF4
SCl2
PI3
IBr
BCl3

The same method works for compounds containing
metals and non metals.
Try these examples:
•Magnesium oxide
•Sodium chloride
•Aluminium iodide
•Potassium sulphide
•Lithium oxide
MgO
NaCl
AlI3
K2S
Li2O

Exercise
2. Tin(IV) chloride
3. Iron(II) oxide
4. Iron(III) sulphide
•Work out the formula for copper(I) chloride and
copper(II) chloride
•Work out the formula for the following transition
metal compounds:
1. Copper(I) oxide Cu2O
SnCl4
FeO
Fe2O3

Chemical Reaction
 A chemical reaction occurs when one or more
chemicals react to become different chemicals.
 A chemical reaction is characterized by the re-
arrangement of atoms from the reactant side of
the equation to the product side.
-: Example :-
Hydrogen gas burns in oxygen to make water.
2H2 + O2 2H2O

Types of Chemical Reaction
 Decomposition Reactions
 Combination Reactions
 Single-Replacement Reactions
 Double-Replacement Reactions
 Combustion Reactions

Decomposition Reaction
A decomposition reaction is a reaction in which
a single compound decomposes to two or
more other substances.
AB A + B
Where A and B can be elements or compounds.
Most compounds can be broken down into simpler
substances or decomposed.

-: Example :-
The industrial preparation of calcium oxide (Lime)
involves the decomposition of calcium carbonate
by heating it.
CaCO3(s) CaO(s) + CO2(g)

Combination Reaction
A combination reaction is a reaction in which
two substances combine to form a third.
A + B AB
Where A and B can be elements or compounds.
Decomposition and combination reactions can
be considered to be the reverse of each other.

Combination Reaction
-: Example :-
The reaction of calcium oxide with sulfur dioxide
to form calcium sulfite
CaO(s) + SO2(g) CaSO3(s)

Single-Replacement Reaction
A single-replacement reaction is a reaction in
which an element reacts with a compound and
replaces another element in the compound.
A + BC AB + C
Where A and C are elements and BC and AB are
compounds.

Single-Replacement Reaction
-: Example :-
The reaction in which copper displaces silver
from an aqueous solution of silver nitrate
Cu(s) + 2AgNO3(aq) Cu(NO3)2(aq) + 2Ag(s)

Double-Replacement Reaction
A double-replacement reaction is a reaction in
which there is an exchange of positive ions between
two compounds. These reactions generally take
place between two ionic compounds in aqueous
solution.
AB + CD AD + CB
Where A and C are cations and B and D are anions.
For a double-replacement reaction to occur, at least
one of the products must be a gas or water, or a
precipitate.

Double-Replacement Reaction
-: Example :-
Precipitation reactions are one type of double-
replacement reaction.
AgNO3(aq) + NaCl(aq) AgCl(s) +
NaNO3(aq)

Combustion Reaction
 A combustion reaction is a reaction in which a
substance reacts with oxygen, usually with the fast
release of heat and the production of a flame.
 Organic compounds usually burn in the oxygen in air
to produce carbon dioxide and if the compound
contains hydrogen, another product will be water.
 For example butane burns in air as follows.

Combustion Reaction
-: Example :-
In general:
CxHy + O2 CO2 + H2O
Products in combustion are ALWAYS carbon dioxide
And water.
Combustion is used to heat homes and run
automobiles (octane, as in gasoline, is C8H18).

 The simplest form of description of a
chemical reaction in a shorter form is by
writing it in the form of an equation.
E.g.-
Mg + O2 MgO
 The reactants are written on the left side
and product is written on the right side.
 An arrow is placed between them to
show the direction of reaction.

The equation must contain the correct
formulas for the reactants and products.
The law of conservation of mass must
be satisfied.

• According to the law of conservation of
mass, total mass must be equal on the both
sides of the equation.
• This type of equation is known as a
balanced chemical reaction. E.g.-
2Mg + O2 2MgO
• Here both sides have two atoms of
Magnesium and
two atoms of
Oxygen.

Cl
Cl
Cl
H
H
H
Cl
Cl H H
Cl Cl
H
H
H
Cl
H
Cl
2 2
2 2
2 1
2 1
H2 + Cl2  HCl (unbalanced)
reactants products
H2 + Cl2  2 HCl (balanced)
reactants products
Unbalanced and Balanced Equations

Reactants
1 C
atom
4 H
atoms
Products
1 C atom
4 H
atoms
4 O

Visualizing a Chemical Reaction
2 Na + Cl2 2 NaCl
_1_0_mole
Na
_5 mole Cl2
_1_?0_ mole
NaCl

1. Combination reaction A + B 
AB
AB  A + B
A + BC
 AC +
B AB
+
2. Decomposition reaction
3. Single-displacement reaction
4. Double-displacement reaction
5. Redox reaction

 These type of reactions occur
when two reactants combine to
form one or more products. E.g. –
1. CaO +
H2O
2. C + O2
Ca(OH
)2CO2
 They are generally exothermic reactions
which involve evolution of heat during
reaction.

• The types of reaction in which a single reactant
breaks down to give simpler products are called
decomposition reaction. E.g.-
• When a decomposition reaction is carried out by
heating, it is known as thermal decomposition.
2 H2O 2 H2 + O2

electricity
2 H2O2
2 H2O + O2
Hydrogen Peroxide
Electrolysis of water
2 H2O 2 H2 + O2
AB A + B
General Form
Nitrogen triiodide
2 NI3
N2 + 3
I2

Double-replacement reaction
CaCO3 + 2 HCl  CaCl2 +
H2CO3
General form:
AB +
CD
 AD + CB
Single-replacement reaction
Mg + CuSO4  MgSO4 +
Cu
General form:
A +
BC
 AC + B

•
•
•
If a substance gains oxygen during a
reaction, it is said to be oxidised.
If a substance loses oxygen during a
reaction, it is said to be reduced.
Reactions in which this type of change
occurs is known as Oxidation and
Reduction reactions or Redox reactions.
E.g. –
CuO + H2 Cu +H2O

Introduction
© iTutor. 2000-2013. All Rights Reserved
Chemical bonding provides the energy
necessary to hold two different atoms
together as part of a chemical compound.
Strength of the bond depends on the
molecules or atoms involved in the process
of bond formation.

Types of Chemical Bonding
Ionic Bonds
Covalent Bonds
Hydrogen
Bonds Metallic

Ionic Bonds
An Ionic bond is when an electron leaves
one atom and exothermically enters into
orbit around another. These to oppositely
charged ions now attract each other.
Ionic bonds are generally formed between
metals and nonmetals

Example of Ionic Bond
A classic example of ionic bonding is between Na and Cl. Na is a
silvery metal. It has 1 valence electron. Cl is a yellow-green gas, and
it needs 1 electron to fill its valence shell. If you put the gas and
the metal together, then they will burn as electrons are exchanged.
The metal dissolves and the gas disappears. The ions now have
opposite charges and are attracted to each other by electrostatic
forces. They form a crystal with the rock salt structure.

Covalent Bonds
A type of chemical bond in which there is
mutual sharing of electrons between two
atoms is called covalent bond. It is
further classified into single, double, and
triple covalent bond with respect to
mutual sharing of one, two, and three
bonds respectively.

Example of Covalent Bond
when two hydrogen atoms get close enough together, the attraction
is balanced in both directions and they share the electrons
between them. A covalent bond is made and hydrogen gas (H2) is
formed.
In the hydrogen molecule (H2) the darker area between the two
nuclei shows where the two electrons, which are now shared,
are most likely to be.

Hydrogen Bonds
A hydrogen bond is the attractive force
between the hydrogen attached to an
electronegative atom of one molecule and
an electronegative atom of a different
molecule.
Usually the electronegative atom is
oxygen, nitrogen, or fluorine, which has a
partial negative charge.

Example of Hydrogen Bond
Each hydrogen atom is covalently bonded to the oxygen via a
shared pair of electrons. Oxygen also has two unshared pairs of
electrons. Thus there are 4 pairs of electrons surrounding the
oxygen atom, two pairs involved in covalent bonds with hydrogen,
and two unshared pairs on the opposite side of the oxygen
atom.
Oxygen is an "electronegative“ atom compared with hydrogen.

Metallic Bonds
Metallic bonding is the type of bonding
found in metallic elements. This is the
electrostatic force of attraction between
positively charged ions and delocalized
outer electrons.
Metallic bonding refers to the interaction
between the delocalized electrons and the
metal nuclei.

Example of Metallic Bond
As the metal cations and the electrons are oppositely charged,
they will be attracted to each other, and also to other metal
cations. These electrostatic forces are called metallic bonds, and
these are what hold the particles together in metals.

INTRODUCTION
Redox reaction include all chemical
reactions in which atoms have their
oxidation state changed; in general,
redox reactions involve the transfer of
electrons between species.

 The term "redox" comes from two concepts involved with electron transfer: reduction
and oxidation. It can be explained in simple terms:
• Oxidation is the loss of electrons or an increase in oxidation state by a molecule,
atom, or ion.
• Reduction is the gain of electrons or a decrease in oxidation state by a molecule,
atom, or ion.

OXIDIZING AND REDUCING AGENT
 An oxidizing agent (also called an oxidant or oxidizer) is
a chemical compound that readily transfers oxygen atoms
or a substance that gains electrons in a redox chemical
reaction.
 An oxidizing agent oxidizes other substances
and gains electrons; therefore, its oxidation state
will decrease.

An reducing agent (also called a reductant or reducer)
is the element or a compound in a redox reaction that
reduces another species. In doing so, it becomes oxidized,
and is therefore a electron donor in redox reaction.
 A reducing agent reduces other substances
and lose electrons; therefore, its oxidation state
will increase.

 In simple terms:
* The oxidizing agent is reduced.
* The reducing agent is oxidized.
*All atoms in a molecule can be assigned an
oxidation number. This number changes when an
oxidant acts on a substrate.
*Redox reactions occur when electrons are
exchanged.
 A mnemonic for differentiating the reactions is "OIL
RIG": Oxidation Is Loss, Reduction Is Gain (of
electrons) or "LEO the lion says GER" (Lose Electrons:
Oxidation, Gain Electrons: Reduction).

EXAMPLE
Ca0 + 2 H+1Cl-1  Ca+2Cl-1 + H 0
2 2
 Since Ca0 is being oxidized and H+1 is being reduced,
the electrons must be going from the Ca0 to the H+1.
 Since Ca0 would not lose electrons (be oxidized) if
H+1 weren’t there to gain them, H+1 is the cause, or
agent, of Ca0’s oxidation. H+1 is the oxidizing
agent.
 Since H+1 would not gain electrons (be reduced) if
Ca0 weren’t there to lose them, Ca0 is the cause, or
agent, of H+1’s reduction. Ca0 is the reducing
agent.

BALANCING REDOX REACTIONS
 STEP 1. Split Reaction into 2 Half-Reactions
 STEP 2. Balance Elements Other than H & O
 STEP 3. Balance O by Inserting H2O into eqns. as
necessary
 STEP 4. Balance H with H+ or H2O (see 4a, 4b)
 STEP 5. Balance Charge by Inserting Electrons as
needed
 STEP 6. Multiply Each 1/2 Reaction by Factor needed
to make no. of Electrons in each 1/2 Reaction Equal
 STEP 7. Add Eqns. & Cancel Out Duplicate terms,
where possible

 STEP 4a. In ACID: Balance H by Inserting H+, as
needed
 STEP 4b. In BASE: Balance H by (i) inserting 1 H2O
for each missing H & (ii) inserting same no. of
OH- on OTHER SIDE OF REACTION as H2Os added
in (i)

EXAMPLE
 Complete and Balance Following Reaction:
CuS (s) + NO3
- (aq) Cu2+(aq) + SO4
2- (aq) + NO (g)
 STEP1. Split into 2 Half-Reactions
a.1 CuS
b.1 NO3
-
Cu2+ +
SO4
2- NO
 STEP 2. Balance Elements Other than H & O (It is already balanced).
 STEP 3. Balance O by inserting H2O into equations as necessary.
Cu2+
a.3 CuS + 4H2O + SO4
2-
b.3 NO3
- NO + 2H2O
 STEP 4. ACIDIC, so Balance H by inserting H+ as needed.
a4. CuS + 4H2O
-
+
b4. NO3 + 4H
Cu2+
2-
+
+ SO4 + 8H
NO + 2H2O

Acids
• An acid is a substance that releases H+ ions in
an aqueous solution
– Aqueous means water
• Example: when hydrochloric acid is dissolved
in water, the compound separates into
chlorine ions (Cl-) and hydrogen ions (H+)

Strong Acids
• A strong acid breaks down completely in
water and gives off many H+ ions

Weak Acid
• A weak acid only partially breaks down. It
gives off much less H+ than a strong acid.

Characteristics of Acids
• Acids have a sour taste
• Acids react with metals & carbonates to
produce gas
• Acids contain hydrogen
H

Characteristics of Acids: Taste Sour
• Acids in foods taste sour and produce a
burning or prickling feeling on the skin

Characteristics of Acids
• Since tasting or touching an unknown
chemical is extremely dangerous, other
methods are needed to tell whether a solution
is an acid

Characteristics of Acids: Reacts
with Carbonate
• A safe way to test to see if a solution is an acid is
to place a few drops on a compound that
contains a carbonate (CO3)
• Example: limestone is a rock that contains
calcium carbonate (CaCO3) When an acid touches
a piece of limestone, a reaction occurs that
produces carbon dioxide gas

Characteristics of Acids: Reacts
with Metal
• Acids also reacts with most
metals
• The reaction produces
hydrogen gas, which you
can see as bubbles

Characteristics of Acids:
Contain Hydrogen

Bases
• A base is a substance that releases hydroxide
(OH-) ions in an aqueous solution
• Example: When sodium hydroxide (NaOH) is
dissolved in water, the compound separates
into sodium ions (Na+) and hydroxide ions
(OH-)

Characteristics of Bases
• Bases usually taste bitter
• Bases feel slippery
• Bases contain hydroxide ions (OH-)

Characteristics of Bases: Taste
Bitter
• Example: Baking soda

Characteristics of Bases: Taste
Bitter
• Mild bases in foods taste bitter and feel
slippery, but as with acids, tasting and
touching are not safe ways of testing whether
a solution is a base
• In fact, some strong bases can burn the skin as
badly as strong acids

Characteristics of Bases: Feel
Slippery
• Bases feel soapy or slippery because they
react with acid molecules in your skin called
fatty acids

Characteristics of Bases: Feel
Slippery
• In fact, this is exactly how soap is
made. Mixing base- usually
sodium hydroxide – with fatty
acids produces soap
• So when a base touches your
skin, the combination of the base
with your own fatty acids
actually makes a small amount
of soap

Characteristics of Bases:
Contain Sodium
Hydroxide (OH-)
Strong Bases The Formulae
Lithium hydroxide
Sodium hydroxide
Potassium hydroxide
Rubidium hydroxide
Caesium hydroxide
Barium hydroxide
Calcium hydroxide
Strontium hydroxide
LiOH
NaOH
KOH
RbOH
CsOH
Ba(OH)2
Ca(OH)2
Sr(OH)2

Properties of Acids & Bases
• Similarities between acids and bases
– Dissolve in water
– Conduct electricity in aqueous solution
– Can irritate or burn skin

Acid-Base Strength
• pH stands for “potential hydrogen” and is a
measure of how many H+ ions there are
in solution.
• The strength of an acid or base is usually
measured using a pH scale
• The more H+ there are, the lower the pH will
be

Acid-Base Strength
High H+ concentration
Low H+ concentration

Acid-Base Strength
• The numbers of the pH scale usually range
from 0 – 14, but numbers outside this range
are possible
• The middle number, 7, represents a neutral
solution
• A neutral substance is neither an acid nor a
base. Pure water has a pH of 7

Acid-Base Strength
• pH < 7 indicate acidic solution
• pH = 7 indicate neutral solution
• pH > 7 indicate basic solution

Acid-Base Strength
• A concentrated strong acid has a low pH value
• A concentrated strong base has a high pH
value

Acid-Base Indicators
• An acid-base indicator is a compound that will
change color in the presence of an acid or
base
• Litmus is a plant extract that can be blue or
red (pink)
– Litmus turns red/pink in an acidic solution
– Litmus turns blue in a basic solution

• The color of hydrangea flowers is dependent
upon the pH of soil

• It would be impossible to determine the pH of
all solutions using just one indicator, such as
litmus
• Several other acid-base indicators exist, each
producing a color change at a specific pH level

• A universal indicator is a mixture of chemicals
that changes color through a wide range of
pH values

Acids and Bases Neutralize Each
Other
• The salts formed may be soluble in
water or can be insoluble
• If the salt is insoluble, a precipitate
will form
• Recall: a precipitate is a suspension
of a small, solid particles formed
during a chemical reaction

Other
from an acid/base reaction
NaCl !!
• General formula for acid base reaction
Acid + Base → H2O + Salt
HCl + NaOH → H2O +
NaCl
• Salt means any ionic compound formed

Other
• A common example of neutralization reaction occurs
when you swallow an antacid tablet to relieve an
upset stomach.
• The acid in your stomach has a pH of about 1.5 due
to mostly hydrochloric acid produced by the stomach
lining

Other
• An antacid tablet contains a base, such as sodium
bicarbonate, magnesium hydroxide or calcium
carbonate. The base reacts with the stomach acid
and produces a salt and water.
• This reaction lowers the acidity and raises to pH to its
normal value (about 2)

REFRENCES
1. Rayner- Canham, G. Descriptive Inorganic Chemistry;
Freeman:New York,1996; Chapter 9
2. Douglas, B; McDaniel, D.; Alexander, J. Concepts and Models of
Inorganic Chemistry, 3rd ed.; Wiley & Sons: New York, 1994;
Chapter 8.
3. J. Kotz, P
. Treichel, J. Townsend, D. Treiche, Chemistry &
Chemical Reactivity, 9th ed. ; Cengage Learning.
4. J.E. Huheey, E.A. Keiter, R.L. Keiter, O.K. Medhi, Inorganic
Chemistry: Principles of Structure and Reactivity, 4th ed. ; Pearson
Education.
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