Physical Sci Reviewer

ELEMENT- It is a pure substance made up of one kind of atom. Nucleosynthesis-The process of creating new atomic nuclei

from preexisting nucleons (protons and neutrons)

Nuclear Reactions-It is the processes in which a nucleus either combines with another nucleus or splits into smaller. BIG BANG THEORY- is the accepted theory that explains the

formation and expansion of the universe. (Hydrogen, Helium)

SINGULARITY>INFLATION> COOL DOWN

Seconds after the explosion of Big bang, protons, neutrons and electrons were made. Protons and nuetrons fused

forming heavier nuclei of deuterium, tritium and helium. Isotopes: Element that possesses the same atomic number but a different mass number. STELLAR FORMATION AND EVOLUTION: Starting from a small, young, yellow star, successive nuclear

reactions which leads to the formation of main-sequence

star - fusion shells. Successive nuclear reactions occurred

until it became a RED GIANT STAR. The reactions that

produced new element in the region called FUSION SHELLS

(Region of formation of new elements "Onion skin structure"). Hydrogen core is the first step in the formation of the stars by means of nuclear fusion and the proton- proton chain

reaction(stars fuse hydrogen into helium). CARBON FORMATION: Thru the triple alpha processes

resulting to the formation of 12 Carbon. This happens once

the temperature of the core is exceeding 100 million degree. (Elements up to Fe)

STELLAR EXPLOSION This happens once the red giant are

exhausted the nuclear fuel of light elements, its ocre started

to collapse that eventually led to the explosion of star. This

violent explsion is called Supernova which released a huge amount of nuclear energy and produced through neutron

capture (nucleus captured neutrons forming heavier

isotopes of the elements that was either stable or

radioactive) and radioactive decay, the other (elements heavier than Fe.)

Beta decay

S-process - slow capture in red giants of neutron by the atom

R-process - rapid capture of neutrons by the atom

Lesson 2: Nuclear Reaction KEY TERMS:

ELECTRON- - charge PROTON- + charge NEUTRON- no charge ALPHA PARTICLE- high-speed particle consisting of 2

protons and 2 neutrons. BETA PARTICLE - high-speed electron. NUCLEAR REACTIONS - process in which a nucleus either combines with another nucleus (through nuclear fusion) or splits into smaller nuclei (through nuclear fission)

DIFFERENT TYPES OF NUCLEAR REACTION: 1. Alpha decay: alpha particles consists of two nuetrons and

two protons. It is the same as helium nucleus. When an

atom's nucleus decays and releases an alpha particles, it

losses two protons and two neutrons mass The number of protons has changed so the decayed atom

has changed into a new element.

2. Beta decay : consists of a high-energy electron, which is emitted by the nucleus of the decaying atom. When an

atom's of nucleus decays and release beta particles, a neutron will turn into proton which stays in the nucleus and a high energy electron, which is emitted.

3. Gamma decay: gamma radiation is a form of electromagnetic radiation, not a type of particle. When an

atom's nucleus decays and emits gamma radiation, it releases energy in the form of electromagnetic radiation. There is no change to the make up of nucleus and so a new

element is not form. Gamma rays are usually emitted with

alpha or beta particles.

4. Electron capture:A neutron-poor nucleus can decay by either positron emission or electron capture (EC), in which an

electron in an inner shell reacts with a proton to produce a neutron: The capture of electron allows a proton to change

into neutron.

Electron capture does not change the mass number however, the atomic number is lower by 1. (Positioned at the middle of

the reaction)

5. Positron emission: The opposite of beta decay. Thus positron emission is characterized of neutron-poor nuclei, which decay by transforming a proton to a neutron and

emitting a high-energy positron. In positron emission mass number does not change however, the atomic number is

lower by 1.

Lesson 3: Synthesis of elements in the laboratory

ELEMENTS IN PERIODIC TABLE

Atomic number=number of protons=number of electron Mass number=proton + neutron Neutron=proton - mass number

• Atom is the basic unit of a chemical element. 5th century BCE: Leucippus and Democritus proposed that matter is made up of indivisible particles or atomos (atom). Leucippus: started the idea and thought that atoms had to

exist because things were constantly changing in nature. Democritus: atoms are indivisible and uncuttable, thus

regarded as the basic building blocks of nature and universe. Aristotle (450 BCE): He thought that all materials on Earth were not made of atoms, but of the four elements, Earth, Fire, Water, and Air. In 1803, John Dalton (Father of Modern Atomic Theory)

presented the atomic theory. Known as Dalton's atomic

theory states that all matter was composed of atoms, indivisible and indestructible building blocks. 1. Everything is composed of atoms. 2. All atoms of a given element are identical in mass and

properties 3. Compounds are combinations of two or more different

types of atoms. 4. A chemical reaction is a rearrangement of atoms ATOMIC MODELS

In 1897, Joseph John Thomson conducted It experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. "Plum

Pudding Model" — defined by electrons surrounded by a

volume of positive charge

In 1919, Ernest Rutherford — former student of JJ. Thomson — discovered the dense atomic nucleus by bombarding a

thin gold sheet with the alpha particles emitted by radium. Nucleus is the center of the atom and he discovered the positively charged particle inside the nucleus as proton. 1915, Niels Bohr proposed the Bohr Model of the Atom. In

his model, electrons orbit the nucleus. (Rutherford-Bohr Model)

In 1932, James Chadwick discovered the uncharged particle

in the center of the atom by conducting an experiment in which he bombarded beryllium with alpha particles. Chadwick discovered the existence of neutrons located in

the nucleus with the protons. THE ARRANGEMENT OF ELEMENTS

94 natural occurring elements 24 synthetic elements Dmitri Mendeleev - first person to arrange and make the first

periodic table of elements (increasing atomic number)

The Discovery of the Missing Elements 1937, Ernest Lawrence synthesized element with atomic number 43 using particle accelerator. He bombarded molybdenum (Z=42) with fast-moving neutrons. The newly synthesized element was named Technetium (Tc) after the Greek word "technêtos" meaning "artificial." Tc was the first man-made element. In 1940, Dale Corson, K. Mackenzie, and Emilio Segre discovered element with atomic number 85. Using bismuth

(Z=83) with fast-moving alpha particles in a cyclotron. The S- process can produce elements up to #83 - Bismuth. Element

-85 was named astatine from the Greek word "astatos" meaning unstable. The two other elements with atomic numbers 61 and 87 were discovered through studies in radioactivity. Element-61

(Promethium) was discovered as a decay product of the

fission of uranium while element-87 (Francium) was discovered as a breakdown product of uranium. Superheavy elements are elements with atomic numbers beyond 103. HOW CAN ELEMENTS BE MADE IN LABORATORIES?

Synthetic elements - refers to chemical elements formed in a laboratory. Through

certain, man- controlled processes. Transuranium elements- these are elements heavier than Uranium; those with atomic numbers greater than 92. Particle accelerators (used to form and accelerate protons to hit target nuclei causing an addition of a proton to the target element) and cyclotron (type of particle accelerator which repeatedly propels a beam of charged particles

(protons) in a circular that produced high-energy particles upon hitting heavy target nuclei produce heavier nuclei. Back on 1913, Henry Moseley, sought to fix Dmitri Mendeleev's arrangement of the periodic table of elements. He said that every element's identity is uniquely determined by the number of protons it has. Processes that produce synthetic elements: 1. Neutron bombardment initiate nuclear fission reactions and causes an element to absorb a neutron, thereby

becoming a heavier isotope of that element. Nuclear bombardment reactions create changes in the nucleus of an

atom or atoms, these changes can produce new element. 2. Fusion of heavy elements with lighter elements such

as hydrogen, helium, carbon, nitrogen, or oxygen can be made to occur in cyclotrons and particle accelerators; the particles are brought together with just enough energy to

overcome the mutual repulsion of the positively-charged

nuclei and cause the elements to fuse together, forming a heavier element in their place. Sometimes this process is

referred to as cold fusion. 3. Particle accelerator used to form and accelerate protons

to hit target nuclei causing an addition of a proton to the

target element. Example: Technetium (Tc) was the first synthetic element result from the bombardment of molybdenum (Mo) using particle accelerator called cyclotron. These are the synthetic or artificial elements as of now aside

from Technetium. Lesson 4: Polarity of a Molecule POLARITY, in chemical bonding, the distribution of electrical charge over the atoms joined by the bond. CHEMICAL BOND is an electrical attraction between the nuclei and valence electrons of an atom. Are formed when

atoms lose, accept or share electrons. Often called as

Intramolecular forces. VALANCE ELECTRONS are the electrons that form the outermost shell of an atom. THREE TYPES OF CHEMICAL BONDS: A. lonic bond: Occurs when there is a transfer of or more

valence electrons form one atom to another. It exists between metal and nonmetal atoms where metal loses electron/s while nonmetal accepts the electron/s donated by metal. B. Covalent bond: sharing of an electron pair between atom

exists. Occurs between nonmetals. Two types of Covalent bond: 1. Polar covalent-partially charge atoms are held together by unequally shared electrons. (HCl, Water, Methanol, Ammonia)

2. Nonpolar covalent is a bond in which electrons are equally shared by the bonded atoms. (H, Cl, O, N)

TYPE OF BOND

Ionic ≥1.7

Polar Covalent 0.5 to 1.6

Nonpolar Covent ≤0.4

GEOMETRICAL SHAPE OF MOLECULES is the three- dimensional arrangement of the atoms and chemical bonds

in a molecule. VSEPR Model

The valence shell electron pair repulsion (VSEPR) model

focuses on the bonding and nonbonding electron pairs present in the outermost (valence) shell of an atom that connects with two or more other atoms. C.Metallic bonds

IONS: an atom or molecule with a net electric charge due to

the loss or gain of one or more electrons Two types. Cations are positive ions formed by losing

electrons and an Anions are negative ions are formed by electron gain POLARITY OF MOLECULES IS DETERMINED BY TWO

FACTORS: 1. ELECTRONEGATIVITY Is the ability of an atom to attract electrons towards itself. Lesson 5: Intermolecular Forces of Attraction ATOM- smallest unit of a substance. MOLECULE- combination of atoms. SUBSTANCES are composed of millions of such molecules. Intramolecular forces are the forces between the atoms. Intra means within or inside. Three types of this forces are

Ionic, Covalent, and metallic. Intermolecular forces (IMFA) are the forces of attraction between molecules. THREE COMMON TYPES: WEAKEST TO STRONGEST

NOTE: The strength of IMFA greatly affects the physical

properties of substances 1. London dispersion forces: This is the weakest among the

intermolecular forces. ALL substances and solely for nonpolar molecules and noble gases. Examples: 02, N2, He gas, Br2

2. Dipole-dipole forces: are property of polar molecules. This

kind of force is stronger than London dispersion forces because polar molecules have a permanent uneven distribution of electrons.

3. Hydrogen bond: Is a bond between hydrogen molecules bonded to an electronegative atom such as fluorine, oxygen, or nitrogen. It is the strongest intermolecular force of attraction among the three. Examples: H2O, NH3, СНЗОН

. 4. ION-ION INTERACTION-it is particle, atom or molecule with a net electric charge.Ex: Ionic bond is the complete

transfer of valence electrons between atoms. It is an

interaction between oppositely charged ions. Occurs usually

in lonic Compounds The PHYSICAL PROPERTIES of molecules depend upon the

type and strength of their intermolecular forces of attraction. SOLUBILITY is the ability of a solid substance to be dissolved in a given amount of solvent while MISCIBILITY is the ability of the two liquids to combine or mix in all proportions, creating a homogenous mixture. The general rule to remember about the solubility and miscibility of molecular compounds "like dissolves like" or "like mixes with like". This means that polar substances will only be dissolved or mixed with polar substances while nonpolar substances will be soluble or miscible with another nonpolar substance. BOILING POINT: temperature at which the vapor pressure and atmospheric pressure of a liquid substance are equal. MELTING POINT: temperature at which solid becomes liquid. At this point, the solid and liquid phases exist in equilibrium. SURFACE TENSION: energy needed to increase the surface area by a unit amount;

VISCOSITY: the resistance of the liquid to flow

VAPOR PRESSURE:pressure exerted by a substance in its gaseous state. VOLATILITY: measures the rate at which a substance

vaporizes (changes from liquid to gas) If the IMF are very strong, the matter will exist as solid. If they are relatively weak, then the compound exists as liquid. If they are weakest, then the compound exists as a gas. Why

intermolecular forces is important?Because it will dictate the properties (physical and chemical) of a substance.

Lesson 6: Biomolecules Biomolecules - Refers to the molecules that occur naturally

in living organisms. Saccharide - the unit structure of carbohydrates Monosaccharide - simplest form of carbohydrates Monomer - a molecule that can react with other molecule to

form very large molecules or polymers Peptide-short chain of amino acid monomer link by peptide bonds Hormones - special chemical messengers that are created in

the endocrine gland

Amino acids - organic compounds that combined to form

proteins Enzymes - proteins which make the bio chemical reaction

fast

Nucleotide- made up of three components: nitrogen- containing base, five-carbon sugar, and a phosphate group

Phospholipids - contain glycerol, two-fatty acids, and a phosphate group. Classification of Biomolecules 1. Carbohydrates: carbon, hydrogen, and oxygen. Most abundant macromolecules on Earth. Good source of energy. Classified either as simple or complex. Simple sugars are monosaccharide and

disaccharides. Complex sugars are polysaccharides. Monomer: saccharides Examples: rice, cereal, potatoes, fruits, pastas Function: main energy source of the body. Glycogen is a

slow-releasing carbohydrate. 2. Lipids or Fats: Carbon, hydrogen, and oxygen They are soluble (dissolve) in oil but are insoluble (don't

dissolve) in water.

lipids: triglyceride, phospholipid, wax, and steroid. Examples: fats and oils are under triglycerides because they are composed of glycerol and three fatty acids. Function: long-term storage of energy in the body. Fat refers to solid triglyceride usually from animal sources

such as meat, milk, butter, margarine, eggs, and cheese. Oil refers to liquid triglycerides from plant sources. Examples: olive oil, corn oil, sunflower oil,

Monomer: fatty acid

3. Proteins: Carbon, hydrogen, oxygen, and nitrogen. Sulfur and other metals are sometimes also found in proteins. If carbohydrates are made up of saccharides, proteins are made up of amino acids. Examples of proteins and their functions are: 1. Keratin is a structural protein found in hair, skin, and nails. 2. Fibroin / Silk protein - Fibroin is found in silk. Silk has a

smooth and soft texture and strongest natural fibers that

have high resistance to deformation. It is also a good

insulating material. 3. Collagen is a major insoluble fibrous protein found in

connective tissues such as tendons, ligaments, skin, cartilage and the cornea of the eye. It comprises as much as 30% of proteins in animals. 4. Enzymes function to catalyze chemical reactions. They either speed up a reaction, lower the needed energy for a

reaction to take place, or bind substances to their specific partners. Examples of enzymes a. Lipase help in digestion of fats b. Pepsin - help in breaking down proteins into peptides

(smaller units) c. Sucrase - also called invertase; help in the digestion of sugars and starches 5. Myoglobin is a polypeptide that stores oxygen in muscles. It contains a heme group which has an iron where the oxygen is stored. 4. Nucleic Acids: Carbon, hydrogen, oxygen, nitrogen, and phosphorus. Most important biomolecules in the continuity of life. Monomer: nucleotide Examples: DNA and RNA

Function: involves the genetic materials, Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA). DNA is the blueprint of life because it contains instructions on how to make proteins in the body. RNA, on another hand, carries the information from the DNA to the cellular factories

for the synthesis of proteins. Three parts of nucleotide: 1. Nitrogenous base 2. Five-carbon carbohydrate or sugar

3. Phosphate group

Lesson 7: Rate of Reaction BIOLOGICAL.MACROMOLECULES ● It is an important cellular molecule.that performs various wide range ofnlife processes for sustaining it. CHEMICAL CHANGE ● Occurs when new substances that have different characteristics are formed; in a physical change no new

substances are formed. COLLISION THEORY ● states that reacting substances must come into

contact/collision (collide) with enough activation energy, and

in the correct orientation (facing the correct way), so that

their electron shells can rearrange to form the products of

thenreaction. Chemical Reaction ● When two particles collide, sometimes a chemical reaction

can occur, which means the bonds between two or more particles are broken and reformed, creating one or more new

substances. The substances or particles that enter and is changed in the chemical reaction are called REACTANTS and

the substances that are formed are called PRODUCTS. reaction rate of a chemical reaction

-is a measurement of the increase in the concentration of a product or the decrease in the concentration of a reactant as

the reaction proceeds over time. Factors Affecting the Rate of Reaction 1. Activation Energy - refers to the minimum energy required

for a reaction to take place. 2. Temperature - refers to how hot or cold a certain

substance is. 3. Concentration - The rate of a chemical reaction is affected

by the concentration of reacting substances. The term

concentration refers to the number of particles present in a given volume of solution. Concentration may also mean a measure of how much of the solute (something to be dissolved) is dissolved in a solvent (dissolving medium) to

form.a homogeneous mixture. 4. Surface Area and Particle Size - Surface area is the measure of how much exposed area a solid object has, expressed in square units. CATALYST - It is a substance that speeds up a chemical reaction, or lowers the temperature or pressure needed to

start one, without itself being consumed during the reaction. Types of catalyst HETEROGENEOUS CATALYST

The reactants and the catalyst are in different phases. ● HOMOGENEOUS CATALYST

Reactants and the catalyst are dispersed in single phase, usually in liquid. ● BIOLOGICAL CATALYST

Enzymes are biological catalyst. Enzyme catalyst is usually

homogeneous because the substance and enzymes are present in aqueous solution (solvent is water)

1..According to the collision.theory, there are three (3)

requirements for a reaction to occur these are: •1. Collision of particles

•2. Activation energy, and

•3. Correct orientation 2. The factors that can affect the rate of reaction are

•1. Activation energy, •2. Concentration, •3. Temperature, and

•4. Surface area/ particles size 3. Increasing the.concentration of reactants in a solution

increases the frequency of collision of particles and the rate of reaction. 4. Increasing the temperature increasing the collision of

particles. Increasing the temperature increases the kinetic energy of particles. 5. The greater the size of particles, the smaller is the surface area. The smaller the size of particles,.the greater is the

surface area. 6. Remember, not all reactions happen at the.same speed. Some are slow/slower while others are fast/faster. Lesson 8: Chemical Equation Chemical equation - Describes a chemical change. Reactant - The chemical(s) you start with before the reaction. Written on left side of equation. Product - The new chemical(s) formed by the reaction. Right side of equation. Subscript - shows how many atoms of an element are in a molecule. Coefficient - shows how many molecules there are of a particular chemical.

The Law of Conservation of Mass states: (Lavoisier, 1788)

that mass is neither created nor destroyed in any chemical reaction. Therefore balancing of equations requires the

same number of atoms on both sides of a chemical reaction. The number of atoms in the Reactants must equal the Number of atoms in the Products The mass of all the reactants (the substances going into a

reaction) must equal the mass of the products (the

substances produced by the reaction). Reactant + Reactant = Product

1. Matter cannot be created or destroyed. 2. Subscripts cannot be added, removed, or changed. 3. You can only change coefficients. 4. Coefficients can only go in front of chem. formulas...NEVER in the middle of a formula. Lesson 9: Energy

Energy is the ability to do work. It can not be created nor destroyed just transferred from one

form to another. 2 types of energy resources Renewable energy resources will not run out because they can easily be regenerated. The Sun is the original source of most energy resources. Plants store the Sun’s energy through photosynthesis. Animals then eat the plants. (WGSHB)

Wind Power Wind has been used in centuries to move ships and pump water. •Wind turbines are installed in strategic locations to harness

the mechanical energy from wind. •Main examples of wind turbines in the Philippines are the ones found in: •San Lorenzo, Guimaras (Trans Asia Renewable Energy Corp

-TAREC)

•Bangui Bay, Ilocos Norte (North Wind Power Devt Corp)

•Burgos, Ilocos Norte (EDC Wind Power Corporation). 2. Geothermal •Geothermal power is the main source of energy in the Visayas region. •Around 38% of electricity in Visayas is produced fro

othermal power. •Geothermal energy comes from deep inside the earth due to

slow decay of radioactive particles in the earth's core. •It is a renewable energy source because heat is continuously produced inside the earth. •Steam released from volcanic vents, hot springs or geysers

is evidence providing that there is thermal energy beneath

the Erath’s surface. This same steam can be used to power

turbines to generate electricity. 3. Solar Power

•Energy from the sun. Solar panels are composed of photovoltaic cells or cells that convert light to electricity. •Panels are comprised of two semi-conducting metals, usually silicon, layered to create a sandwich. 4. Hydroelectric

•Hydroelectric power (often called hydropower) is considered a renewable energy source. •Through hydropower, the energy in falling water is converted into electricity without “using up” the water. •The strength of the current is a good reference on where the power plant may be constructed. •This is the main source of electricity in Mindanao, generating around 45% of electricity in the region. •Dams are installed in strategic locations where there is a

substantial drop in elevation. •One of the environmental concerns related to hydroelectric power is the displacement of marine species. 5. Biomass

•Biomass refers to organic matter from plants and animals

(microorganisms). •Plants get their energy from the sun through the process of

photosynthesis which, in turn, gives energy to animals upon

consumption. •Wastes such as crop remains, manure, and garbage are good sources of biomass. •Wood is also a biomass fuel. •As long as we replenish the trees that we cut, biomass can be a sustainable energy source. •Biomass is used to create methane and alcohol which are

fuels useful in energy production and in powering

automobiles. •Production of biogas or biofuels involves the action of

microorganisms that break down organic matter in a multi- step process. •Technologies utilizing biomass are continuously evolving in order to improve efficiency. A NONRENEWABLE RESOURCE is a natural resource that cannot be re-made or re-grown at a scale comparable to its consumption. 1. Fossil Fuels

•It includes hydrocarbons such as coal, oil, and natural gas

that comes from organic remains of prehistoric organisms. •Coal is the world’s most abundant fossil fuel. It is relatively

inexpensive and is readily available. •The energy that comes from fossil fuels came from the sun

through the process of photosynthesis when the prehistoric plants were still alive. •In the Philippines, around 69% of our electricity is derived

from fossil fuels (coal, oil, natural gas, biomass). •In the world, around 75% of our energy is generated by combustion of fossil fuels. •Power plants burn fossil fuels and the heat generated

during this process is used to turn water into steam and this

turns the turbines. 2. Electrochemical (batteries)

•Batteries give electricity via an electrochemical reaction. •It has three main parts: anode, cathode, and electrolyte

•The first battery was invented by Alessandro Volta, an

Italian physicist. His invention of the battery propelled

studies on electricity as it allowed scientists to produce

electricity. •Batteries, compared to other sources, have low intensity but

they are commonly used since they are portable and efficient. Lesson 10: Active Ingredients of Cleaning Products Used at

Home CHEMISTRY is the science that deals with the properties, composition, and structure of substances (defined as elements and compounds), the transformations they undergo, and the energy that is released or absorbed during

these processes (Usselman, 2019). Definition of terms: ACID-classified as a compound with distinctive properties. An acidic substance is sour-tasting; reacts with litmus paper, bases and metals; conducts electricity; and has a pH of less

than 7. An acid can be classified as strong or weak based on

its reactivity, conductivity, and pH. pH Scale – used as a measure of how acidic or basic a

substance is. LITMUS PAPER strips are used as a general indicator to

determine acidity. When dipped in or rubbed on an acidic

substance, blue litmus paper turns red. An ALKALI or chemical base is a caustic substance. It is a

substance that accepts hydrogen ions. It dissociates in water and is a good conductor of electricity. An alkali turns litmus paper blue. ACIDS AND BASES are generally chemically active and can

react in many other substances. Because of this characteristic, they are commonly found in household

applications, especially as cleaners and as ingredients in

cooking. Understanding the properties of the chemical ingredients active in the following cleaning materials: 1. Sodium hypochlorite appears as colorless or slightly yellow watery liquid with an odor of household bleach. It mixes with water. (USCG, 1999). It is used as a bleaching agent, laundry bleaching agent, disinfectant for glass, ceramics, and tiles. 2. Sodium bicarbonate appears as odorless white crystalline powder or lumps with

slightly alkaline (bitter) taste. It is used to make many chemicals, as an ingredient in baking powder, effervescent salts (granules, or coarse to

very coarse powders, containing the medicinal agent in a dry mixture usually composed of sodium bicarbonate, citric acid, and tartaric acid to disperse medicines in water for oral administration.) and beverages, in fire extinguishers, cleaning compounds, and in human and veterinary

pharmaceuticals. Workers that use sodium bicarbonate may breathe in mists or have direct skin contact. Sodium bicarbonate is a Generally Regarded as Safe (GRAS) chemical at levels found

in consumer products, and has a low risk of toxicity in

humans. It is a slight skin and eye irritant. 3. Sodium hydroxide At room temperature is a white crystalline odorless solid that absorbs moisture from the air. It is a manufactured

substance. When dissolved in water or neutralized with acid

it liberates substantial heat, which may be sufficient to ignite

combustible materials. Sodium hydroxide is very corrosive. It is generally used as a solid or a 50% solution. Other common names include caustic soda and lye. It is used to manufacture soaps, rayon, paper, explosives, dyestuffs, and

petroleum products. It is also used in processing cotton

fabric, laundering and bleaching, metal cleaning and

processing. It is commonly present in commercial drain and

oven cleaners. When inhaled, cough, sore throat, burning sensation and

shortness of breath may be experienced. 4. Boric acid

is a white crystalline solid It is a weak inorganic acid with

antiseptic properties, and is also called boracic acid or orthoboric acid. It is non-toxic with antibacterial properties.

it is mainly used as an antiseptic agent, acne treatment, preservative, insecticide, pH buffer (special solutions which

prevent large variations in pH levels), swimming pool chemical, flame retardant (various chemicals applied to materials to prevent burning or slow the spread of fire) , and

a precursor to many useful chemicals. 5. Hydrochloric acid also known as muriatic acid

is colorless -light yellow in appearance, has a pungent and

irritating odor. Although it is highly corrosive, it is used to remove stains

from metals. It can clean iron, copper, brass and other metals; however, one should dilute it by adding 9 parts of water to 1 part of the acid. One should not use it directly on metals as it is extremely powerful cleaning agent. 6. Formaldehyde

is a liquid which is clear or water-white. The odor is irritating

and pungent. It is soluble in water and up to 55 percent soluble in ether, acetone, benzene, and alcohol. An aqueous solution of formaldehyde can be useful as a disinfectant as it kills most bacteria and fungi (including

their spores). Also used for the preservation of animal specimens. Formaldehyde can cause irritation of the eyes, nose, and

throat, even at low levels for short periods. Longer exposure or higher doses can cause coughing or choking. Severe

exposure can cause death from throat swelling or from

chemical burns to the lungs 7. Sodium Lauryl Sulfate appears as white to pale yellow paste or liquid with a mild odor, sinks and mixes with water, (USCG, 1999) naturally

derived from coconut and/or palm kernel oil. It usually consists of a mixture of sodium alkyl sulfates, mainly the

lauryl. SLS lowers surface tension of aqueous solutions and is used

as fat emulsifier (Fat emulsification is the process of

increasing the surface area of fats in the small intestine), wetting agent (a chemical that can be added to a liquid to

reduce its surface tension and make it more effective in

spreading over and penetrating surfaces), and detergent in

cosmetics, pharmaceuticals and toothpastes. It is also used

in creams and pastes to properly disperse the ingredients and as research tool in protein biochemistry. SLS also has

some microbicideactivity. It is used in electrophoretic

separation of proteins and lipids.

8. Ethanol (commonly called ethyl alcohol, drinking alcohol, or simply alcohol is the principal type of alcohol found in

alcoholic beverages, produced by the fermentation of sugars by yeasts.

is a clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It

has bactericidal activity and is used often as a topical

disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in alcoholic beverages.