Natural

Science 1

Chemistry Part

Dr. Florenda S. Valera

Institute of Chemistry

UP Diliman

�Classes start on time and end 10-15 mins before

allotted time

�You may ask questions at any point during the

lecture.

�During exams : you may look upward for

inspiration, downward in desperation but not

sideways for information.

�Turn off all electronic gadgets.

Some policies

�Readings in Natural Science I -Chemistry Portion, available at Rm. PH 1203A

�The Extraordinary Chemistry of Ordinary Things, by Carl Snyder, John Wiley and Sons, Inc.

�Any General Chemistry Book

References

Grading system

Exemption grade is 50

%

Missed 1 LE, double F.

Present excuse slip.

Missed 1 LE and F,

grade is Inc. if passing;

5.0 if failing. Present

excuse slip

Missed 2 exams, zero

for the 2nd exam.

100x4

LE4grade% =

100x5

F2LE3grade%

+=

100x3

LE3grade% =

100x5

F2LE2grade%

+=

�TTh 10:00 am – 12:00 nn

�WF 1:00 – 4:00 pm

� PH 1214 or PH 1217

Consultation Hours

�One-hour exams

� IDs will be checked

�1st exam on Feb 23: Modules 1-4

�2nd exam on Mar 18: Modules 5-12

Chemistry Exams

History of Chemistry

Prehistoric period Before 1500 BC

Alchemical period 1500 BC to 1500 AD

Iatrochemical period 1500 to 1650

Phlogiston period 1650 to 1775

Quantitative period 1775 to 1900

Atomic period 1900 to 1960

Sub-atomic period 1960 to present

Pre-historic period

(before 1500 B.C.)� From the practical arts to the Greek theories

� Metallurgical processes, cosmetic preparations, drugs and

pottery were empirically developed (based on practical

experience without reference to underlying chemical principles

of the chemical change)

� Shu Ching (Chinese book): everything was made of earth, fire,

water, metal and wood

� Empedocles (Greek, 424 – 484 BC): 4 chief “roots” of matter –

earth, fire, water and air; basic properties – coldness, hotness,

dryness and wetness

� Leucippus and Democritus (5th century B.C.): substances were

made up of basic units called atoms

�Alchemists’ objectives: (1) find the “philosopher’s

stone” that would change lead, iron and other base

metals into gold; and (2) discover or produce the

“elixir of life”

�Roger Bacon (1214 – 1292), English philosopher

and alchemist, laid the foundations for the

experimental method of chemical research by

carefully planning and interpreting his laboratory

work

Alchemical period

(1500 B.C.-1500 A.D.)

� Search for new medicinal substances

�Theophrastus von Hohenheim (1493 – 1541),

better known as Paracelsus, pioneered in

iatrochemistry or the study of the effects of

medicine on the human body

Iatrochemical period

(1500-1650)

� Jan Baptista van Helmont (Belgian 1577 – 1644): air

and water were the only elements, studied gas released

from burning charcoal (gas sylvestre, now known as

carbon dioxide) and fermenting wine

� Robert Boyle (Irish, 1627 – 1691): considered the first

real chemist and the founder of Chemistry

� Georg Ernst Stahl (German) taught that “phlogiston”

escaped whenever a material was burned or when

metals like iron became rusty

� Carl Scheele, Joseph Priestley and Henry Cavendish

supported phlogiston theory

Phlogiston period

(1650-1775)

�Birth of Modern Chemistry

�Antoine Lavoisier (French): father of modern

chemistry, found in 1772 that some burning

objects gained rather than lost weight; combustion

in dephlogisticated air (oxygen) gave the same

products as combustion in air

Quantitative period

(1775-present)

Chemistry is the

central science.

Chemistry

Deals with the study of matter :structurepropertiestransformationsenergy involved in its transformations

☺ Matter is anything that occupies space and has mass.

☺ Matter is the material of the universe.

� Mass is a measure of the quantity of matter.

� Weight is the gravitational force of attraction exerted by the earth on a body.

Some definitions

Properties of matter

�Intrinsic Properties :�Independent of the amount of material�Density (m/v), optical rotation, texture, boiling pt

�Extrinsic Properties :�Dependent on the amount of material�Size, mass, volume, heat content

�Solid

incompressible

definite shape and volume

�Liquid

indefinite shape but definite volume

�Gas

indefinite shape and volume

Phases of matter

Changes that matter may undergo

Physical changes :

No change in the composition of matter

Phase Changes are physical changes :

Melting (S to L) freezing (L to S)

Evaporation (L to G) condensation (G to L)

Sublimation (S to G) deposition (G to S)

Chemical Changes :

�change in the composition of matter

�both intrinsic and extrinsic properties

are changed

� represented by a chemical reaction

Changes that matter may undergo

� Synthesis or combination

A + B → C

� Decomposition

C → A + B

� Single displacement

AD + B → AB + D

� Double displacement

AD + CB → AB + CD

Types of chemical reactions

Can you tell whether the ff is a chemical or a physical change?

1. Burning of wood

2. Formation of snow

3. Ripening of mangoes

4. Digestion of food in the stomach

Test yourself !

Mixtures

• Heterogenous mixtures

made up of two or more phases

indefinite composition and properties

• Homogenous mixtures

made up of only one phase

indefinite composition and properties

• Colloids

intermediate phase

Types of matter

•

Types of matter

Substances

definite composition and properties

�Elements (109 in all)

simplest type of matter

�Compounds

combination of elements in a definite ratio

Molecules

Ionic compounds (cation + anion)

Test yourself !

�Can you tell the type of matter in each number?

1. Vinegar2. Halo-halo3. Smog4. Sand and sugar5. Baking powder6. Salt7. Metal key

�Matter consists of tiny particles

� Atoms are indestructible and

unchangeable

�Elements are made up of the same kind of

atoms

�Elements combine in simple whole

number ratios

Dalton’s Atomic Theory

� Law of Conservation of Matter

Matter is neither created nor destroyed in a chemical reaction.

� Law of Definite Proportion

Elements combine in fixed amounts in a compound.

�Law of Multiple Proportion

Compound and/or elements combine in simple whole number ratios.

Fundamental Laws

� Made up of protons, neutrons and electrons

� Protons and neutrons are called nucleons (nuclear particles)

�Electrons are found outside the nucleus

� Protons are positively charged

� Electrons are negatively charged

� Neutrons are uncharged

Element

•

Element

EA

Z

A – mass number

Z – atomic number

A= number of protons + neutrons

Z= number of protons

For an electrically neutral element : number of protons

is equal to the number of electrons

Isotopes : same atomic number but different atomic

masses

Element

S32

16

Sulfur has :

• 16 protons (Z)

• 32-16 = 16 neutrons (A)

• 16 electrons since it is electrically neutral

Test yourself !

Can you tell the number of protons, neutrons and electrons

in each element ?

Pt

Cl-

195

78

35

17Ra2+226

88

Fe3+55

26