Chemistry Reviewer

WORD Technology Chemistry Matter Volume Mass Weight Properties Structure Laws/ Principles

TERMS DEFINITION Application of science to improve the quality of life The branch of science that deals with matter, its properties, changes ,composition and laws or principles governing the changes Anything that occupies space and has mass Other word for space Amount of matter present in an object (kg, g, mg, lb, oz) Gravitational pull acting on an object (N, dyne) Characteristics/ qualities Arrangement of matter Explanation to the changes

IMPORTANCE OF CHEMISTRY • We need to study Chemistry because we and the environment are matter ant to familiarize the matter around us BRANCH OF CHEMISTRY Biochemistry Analytical Chemistry Organic Chemistry Inorganic Chemistry Physical Chemistry General Chemistry

BRANCHES OF CHEMISTRY DEFINITION Study of organic compounds where humans are made of Analysis of the composition of substances/ materials Study of carbon and its compounds Study of non carbon containing compounds Deals with the energy changes happening in chemical reactions Basic concepts of chemistry STATES OF MATTER

Molecules are compress Molecules are slightly apart

Solid Liquid Gas

Molecules are far from each other

Plasma

A form of gas

Bose-Enstein Condensate

A form of liquid

Definite volume Fixed volume Don’t have fixed volume

SCIENTIFIC METHOD • Systematic way of finding answers in a problem STEPS 1. Know the problem 2. Making observation 3. Making hypothesis 4. Test the hypothesis through experimentation 5. Analyze the data gathered 6. Make a conclusion SCIENTIFIC ATTITUDES

Has definite shape Only occupies the shape of the container Composed of energy charged particles Produced only in a temperature near absolute zero Don’t have fixed shape

1. 2. 3. 4. 5. 6. 7. 8.

Keen observer/ Curiosity Open-mindness/ Objectivity Resourcefulness Intellectual Honesty Patience/ Perseverance Humility Acceptance of failure Healthy skepticism PROPERTIES OF MATTER

PROPERTY Chemical Properties

Physical Properties

DEFINITION Can be observed/ measured only after a matter underwent a change in composition Can be observed/ measured even without the matter undergoing a change in composition

• • •

EXAMPLE combustibility chemical reactivity rusting formation

•

5 senses

• • • • • • •

Mass Volume Taste Odor Density Boiling point Elasticity

• • • • • • • •

EXAMPLE Breaking Melting Freezing Grinding Rusting Decomposition Cooking Digestion

TYPES OF PHYSICAL PROPERTIES Extensive/ extrinsic

Properties that depend on the amount of matter present

Intensive/ intrinsic

Properties that depend on the kind of matter present CHANGES IN MATTER

CHANGE

DEFINITION

Physical Change

Changes that do not alter the composition of substance

Chemical Change

Changes in the composition of substances to form a new substance

Melting

Solid to liquid

Evaporation

Liquid to gas

Sublimation

Solid to gas

Freezing

Liquid to solid (solidification)

Condensation Deposition

Gas to solid

PHASE CHANGES Melting of snow and ice Evaporation of water or refrigerant Sublimation of dry ice, free-drying of coffee Freezing of water or a liquid metal Formation of dew Formation of frost and snow

Heat is absorbed by the matter

Heat is released by the matter

CLASSIFICATION OF MATTER (Classified according to composition) •

Pure substance o A matter that is composed of only one kind of particle KINDS o o o

OF PARTICLES Atoms Molecules Ions

KINDS OF PURE SUBSTANCES o Elements – Periodic Table  Simplest form of matter  Made up of only one kind of atom or molecule METALS Usually hard and solid except Hg, which is a liquid. Cs and

KINDS OF ELEMENTS NONMETALS Some are solid, liquid (bromine), or gas. Usually soft

METALLOIDS Solids

Ga melt in unprotected hand Malleable and ductile Conductor of heat and electricity Lustrous and shiny High density High melting and boiling points High tensile strength

o

except diamond Brittle Basically insulators Dull except diamond Low density Low melting and boiling points Low tensile strength

Brittle Intermediate electrical conductivity Intermediate reflectance Intermediate density Low melting and boiling points Low tensile strength

Compounds  Formed when 2 or more elements combined chemically in fixed proportions

CLASSIFICATION OF COMPOUNDS  According to Composition

•

Organic – C6H12O6 , CH4 o with carbon

•



Inorganic – NaCl , H2O , H2 , SO4 o without carbon According to Chemical Bond • Ionic – M + NM , ENaCI o Ionic bond is present

• •

Covalent – NM + NM , H2O o Covalent bond is present

Mixture o Composed of 2 or more substances that combined physically in variable proportions CLASSIFICATION OF MIXTURE (According to number of phases) o Homogenous/ Solutions – sea water, air  Single-phased mixtures  All the parts are identical o Heterogeneous – Salad, soup, garbage  Mixtures consisting of 2 or more phases  With parts that are dissimilar KINDS OF HETEROGENEOUS  Suspension • The suspended particles can be seen and are large to be trapped in a filter  Colloid • Mixture with particles bigger than the particles of a solution but smaller than those of a suspension  Coarse Mixture • The particles can be separated mechanically • Brownian Movement o Rapid, haphazard motion of colloidal particles o Caused by the collision of the colloidal particles with the molecules of the dispersion medium o Colloidal particles do not settle because of the Brownian Movement • Tyndall Effect o The reflection of light by colloidal particles

• • • •

DIFFERENCE BETWEEN COMPOUND AND MIXTURE COMPOUND MIXTURE Fixed proportion • Variable proportion Cant be separated by ordinary • Cant be separated by ordinary physical means physical means Chemically combined • Physically combined Can be expressed in formulas • Cant be express in formulas

METHODS OF SEPARATING MIXTURES • • • • • •

•

• •

Filtration o The pouring of the mixture through a piece of paper (filter paper) which lets the liquid (filtrate) pass through but catches the solid (residue) Flotation o The removal of suspended particles either by sedimentation or coagulation o Used in mining to separate precious metals/ minerals from impurities Distillation o Makes use of the differences in boiling points (evaporation and condensation). The gas is then condensed back to a liquid (distillate) Decantation o The pouring of the liquid from a mixture to separate the liquid (decante) from the solid particles Crystallization o Occurs when simple sea water is allowed to evaporate Centrifugation o The settling of tiny suspended particles using a centrifuge. Tis hastens the settling of the precipitate in a suspension.  Centrifugate • The liquid that comes from centrifugation Chromatography o A solution ca nbe separated by allowing it to flow along a stationary substance o Uses the different degrees of adsorption of the components to a stationary substance KINDS OF CHROMATOGRAPHY  Paper Chromatography  Column Chromatography Magnetism o Used to separate a metal from a non metal Mechanical Spearation o Use machines to separate mixtures

EVIDENCE OF CHEMICAL CHANGE 1. Change in color, taste, odor 2. formation of a new substance 3. evolution of gas 4. production of heat and light 5. formation of precipitate 6. production of sound and mechanical energy ENERGY • capacity to do work or to transfer heat POTENTIAL ENERGY • the energy stored in an object because of its position or composition KINETIC ENERGY • energy in motion

• • • • • • • •

LAVOISIER, ANTOINE LAURENT (1743-1794) “Father of Modern Chemistry” chemist, politician, lawyer, farmer, banker born in Paris, France on August 26, 1743, son of a wealthy lawyer suited law, also attended lectures on scientific studies in 1771, married Marie Paulze (acted as secretary and made many drawings for his book) they had no children member of “farm General” (collect taxes for the king) during French Revolution; members were arrested tried and sentenced to death on May 8, 1794, Lavoisier was beheaded (guillotine)

IMPORTANT CONTRIBUTIONS • Oxygen Theory of Burning (Phlogiston Theory of Burning) o Accepted explanation of burning

• • •

Found out that water is composed of 2 gases (O2,H2) Explained the respiration process ( the body uses breathened oxygen to burn food, which gives the body its heat) Worked with other chemists to set up a system of naming chemicals

IMPORTANT QUALITIES

• • • • •

Lavoisier didn’t make any discoveries of his own but he gave correct explanations to the discoveries of others He insisted on exact measurements in all his experiments He helped introduce methods of exactness in chemistry He would accept no idea unless it could be proved LAWS OF CHEMICAL COMBINATION Law of Conservation of Mass o The total mass in any chemical or physical change does not change. o The number of substances may change, the properties may change, but the total amount of matter remains constant. Fe S FeS + = (10g) (5g) (15g)

•

Law of Definite Composition o Formulated by Joseph Proust (1754 – 1826), a French chemist o Elements combine to form compounds in definite proportions by mass H2 O + = 2H:1O 11.11% 88.89%

•

Law of Multiple Proportions o When 2 elements combined to form 2 or more compounds, the masses of one element that combined with a fixed mass of the elements are in a ratio of small whole numbers C O 1st compound 3.00g 5.00g 2nd compound 6.00g 10.00g Ratio (mass of O)

=

Mass of O (1st compound) Mass of O (2nd compound)

=

5.00g 10.00g

=

½ or 1:2

DEVELOPMENT OF THE ANATOMIC THEORY •

•

Leucippus (teacher) and Democritus (student) o Believed that the atoms were invisible, indestructible, and the smallest particle of matter called “atomos”. o He believed that these atoms differ in shape, size, weight, sequence, and position Aristotle o Rejected the idea of the atomism of matter o Believed that there’s no limit in subdividing matter 4 ELEMENT THEORY OF EMPEDOCLES  All the matter were made of water, air, fire, and earth

•

John Dalton (1766-1844) o An English chemist and physicist o Stated that his atomic theory based on approximately 150 years of investigation by scientists such as Robert Boyle, Joseph Priestley, and Antoine Lavoisier IDEAS OF JOHN DALTON  Matter is composed of tiny indivisible spheres called atoms  Atoms of the same element are identical, but atoms of one element are different from those of all other elements  Atoms cannot be created or destroyed during a chemical change  Atoms of different elements combine in simple whole number ratios to form compounds

•

William Crookes (1832- 1919) o Studied matter using a powerful vacuum pump called the “Crookes’ Tube” o Discovered the “cathode rays” by connecting the tube to an external source of electricity and noticing that a flash of light or ray coming from the negative electrode (cathode) and moving to the positive electrode (anode)

•

Joseph o o o

John Thomson Gave the name of “electron” to the cathode rays Discoverer of the electrons Used magnetic and electric fields to measure the value of the ratio of the electron charge to its mass

E M o o

•

=

1.759 x 108

coulomb/ gram

Found out that hydrogen is the lightest atom with its mass of 1/1840 Proposed a model of an atom as a positively charged sphere where the electrons are embedded. This model is called the “raisin cake model” or “watermelon model” where the raisins or seeds are the electrons

Robert Millikan (1868- 1953) o Measured the charge of the electron with the use of his oil-drop experiment E = -1.602 x 10-19 coulomb o

And later the results of Thomson and Millikan, the calculation of the mass of an electron (E) -1.602 x 10-19 c (M) -1.759 x 108c/g M = 9.11 x 10-28g = mass of a negative electron

•

Eugen Goldstein o Discovered the canal rays  Particle that were left out of the atoms or molecules after electrons had been pulled out

•

Wilhel Prentgen (145- 1923) o Discovered that highly energetic rays could penetrate matter and later called these “X-rays”

•

Henri Becquerel (1852- 1908) o Associated X-rays with fluorescent materials by using a used uranium ore o Discovered radioactivity (uranium)  Any material such as uranium that spontaneously emits radiation said to radioactive

•

Ernest Rutherford o Discovered the 2 types of radiation from radio active materials –alpha and beta TYPE OF RADIATION Alpha Beta Gamma

SYMBOL

NATURE

CHARGE

a β δ

Helium nuclei Electron Radiant energy

+2 -1 0

PENETRATIN G POWER 1 100 10,000

o Performed the alpha-scattering except to test the raisin bread RESULTS OF THE ALPHA-SCATTERING EXPERIMENT  Most of the gamma particles passed through undeflected • The atom is mostly an empty space

 

o o

A few passed through with large angles of deflection • Gamma particles hit the side of the tiny solid part in the atom A few gamma particles bounced back • They had a “head on” collision with the tiny solid part of the atom

proposed that most of the mass and positively charged parts of the atom, the protons, must be concentrated in a small region called the nucleus Thought that the electrons are distributed in the space outside the nucleus of the atom

•

James Chadwick (1871- 1974) o Atoms of the same element that have the same atomic number but with different atomic mass

•

Isaac Newton o A scientist that works on light o Believed that the light was made of “corpuscles” or particles, although a later theory held that light was made of waves

ISOTOPES • atoms that have the same number of protons but different number of neutrons

ATOMIC NUMBER (Z) • gives the number of protons or electrons in an atom • It is shown by the subscript ATOMIC MASS (A) • gives the sum of the number of protons and neutrons in an atom • it is shown by the superscript EXAMPLES A. NEUTRAL ATOMS 17 13 75 33 B. MONOANATOMIC IONS 24 12 80 35

DALTON MODEL THOMSON MODEL NUCLEAR MODEL BOHR MODEL

Al

Protons : 13 Electrons : 13 Neutrons : 14

As

Protons : 33 Electrons : 33 Neutrons : 42

Mg Br

+2

-1

Protons : 12 Electrons : 10 Neutrons : 12 Protons : 35 Electrons : 36 Neutrons : 45

EARLY MODELS OF AN ATOM Atoms are solid indestructible spheres Raisin bread model Rutherford discovered that the atom possessed a small dense core(nucleus) First quantum model of the atom w/ the electrons following circular orbits around the nucleus

BOHRSUMMERFELD MODEL

Electrons in elliptical orbit

QUANTUM MECHANICAL MODEL

Schrodinger proposed a wave equation from which atomic orbitals are derived. It is concerned w/ the probability of finding a given electron in the space outside the nucleus  Excited state-transfer to higher energy level  Ground state-lowest possible state  Energy absorbed  Energy released-light

QUANTUM NUMBERS • numbers used to describe the probable locations of the electron PRINCIPAL QUANTUM NUMBERS • Tells the number of main energy level where e- can be found o n = 1,2,3,4… o if n = 1 -1st energy level

o o

n=2 -2nd energy level n=3 – 3rd energy level…..

AZIMUTHAL QUANTUM NUMBERS • defines the shape of the orbital • tells the kind of sublevel occupied by the eo l=0–s o l=1–p o l=2–d o l =3 - f MAGNETIC QUANTUM NUMBERS • Describes the orientation of orbitals in space • Tells the number of orbitals occupied by the eo ml = -1 → 0 → +l

o

l = 0 → ml =0 →1 orbital → 2e- → s

o o o

l = 1 → ml = -1 0 +1 →3 orbital → 6e- → p l = 2 → ml = -2 -1 0 +1 +2 →5 orbital → 10e- → d l = 3 → ml = -3 -2 -1 0 +1 +2 +3 →7 orbital → 14e- → f

SPIN QUANTUM NUMBERS • tells how the e- spin in their axes as they revolve around the nucleus o clockwise- Ms= -1/2

o

counterclockwise – Ms = +1/2

ELECTRON CONFIGURATION • arrangement of electrons in an atom RULES TO BE FOLLOWED 1. Aufbau Principle  e- occupy the orbitals in order of increasing energy level 2. Pauli’s Exclusion Principle 3.

 2 e- occupying the same orbital should have opposite spins ↑↓ Hund’s Rule  when e- enter a sublevel w/ more than 1 orbital (p,d,f), e- will occupy first all the available orbitals w/ their spins in the same direction before they can pair up w/ another e- of opposite spin 8e- → ↑↓ ↑↓ ↑↓ ↑ ↑ = d sublevel

THE MODERN PERIODIC TABLE • periods/series o horizontal rows o 7 periods/series • groups/families o vertical columns o 18 groups/families  A-8 groups/families (representative elements) • IA – Alkali metals • IIA – Alkaline Earth Metals • IIIA – Boron group • IVA – Carbon group • VA – Nitrogen group • VIA – Oxygen group • VIIA – Halogen group • VIIIA – Noble gases/ Inert gases  B- 10 groups/families (transition metals/elements) VALENCE ELECTRON • electron in the outer most main energy level DETERMINING THE PERIOD AND FAMILY ON AN ELEMENT

•

11

•

22

Na – 1s2 2s2 2p5 3s1 o n=3 o val e- = 1 o period=3 o family=IA Ti – 1s2 2s2 2p6 3s2 3p6 4s2 3d2 o n=4 o val e- = 2 o period = 4 o family = IVB

DETERMINING ATOMIC NUMBER 1A 2A 3A 4A

ns1 ns2 ns2np 1

ns2np 2

ns2np

5A

3

2

ns np

6A

4

ns2np

7A

5

2

ns np

8A

6

ns1md

1B

10

2

ns md

2B

10

ns2md

3B

1

2

ns md

4B

2

2

ns md

5B

3

ns2md

6B

4

2

ns md

7B

5

ns2md 6

2

ns md

8B

7

2

ns md 8

• •

period-3 Family-3A o 1s2 2s2 2p6 3s2 3p1 o Z = 13

• •

period-4 Family-4A o 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2 o Z = 32

PERIODIC PROPERTIES • Properties of an element seem to be determined largely by the electron configuration of the outermost electrons and by how far away those electrons are from the nucleus IONIZATION ENERGY • Amount of energy needed to remove an e- from atom to form (+) ions • Ionization o when an atom loses or gains electrons to form ions ELECTRON AFFINITY • Amount of energy released when an atom or molecule gains e- forming a (-)ion IONIC RADIUS • Isoelectric o

equal numbers of electrons in identical configurations

ELECTRONEGATIVITY • General tendency of an atom to attract e- toward itself METALLIC PROPERTY • w/ few valence e• tend to give up or donate e→ E, IE, EA ↓AS, MP, IS • •

Octet rule o an atom should have 8 valence e- to become stable Duet rule o needs 2 valence e- to be stable

WAYS OF REPRESENTING AN ATOM • Electron Configuration • Use of Orbitals • Use of Main energy level • Lewis electron dot formula o consists of a chemical symbol surrounded by dots(Gilbert Newton Lewis) • Chemical symbol o represents the nucleus and inner e• Dots o represents the valence e- of the atom