EXPERIMENT I ( BIODIESEL SYNTHESIS )

EXPERIMENT I ( BIODIESEL SYNTHESIS )

WHAT IS BIODIESEL
Biodiesel is defined as the mono-alkyl esters of fatty acids derived from vegetable oils or animal fats. In simple terms, biodiesel is the product you get when a vegetable oil or animal fat is chemically reacted with an alcohol to produce a new compound that is known as a fatty acid alkyl ester. A catalyst such as sodium or potassium hydroxide is required. Glycerol is produced as a byproduct. The approximate proportions of the reaction are:

100 lbs of oil + 10 lbs of methanol → 100 lbs of biodiesel + 10 lbs of glycerol

Biodiesel can also be made from other feedstocks:

1. Other vegetable oils such as corn oil, canola (an edible variety of rapeseed) oil, cottonseed oil, mustard oil, palm oil, etc.
2. Restaurant waste oils such as frying oils
3. Animal fats such as beef tallow or pork lard
4. Trap grease (from restaurant grease traps), float grease (from waste water treatment plants), etc.

Transesterification is the process of reacting a triglyceride molecule with an excess of alcohol in the presence of a catalyst (KOH, NaOH, NaOCN3, etc.) to produce glycerin and fatty esters. The mixture of fatty esters produced by this reaction is known as biodiesel.

EXPERIMENT
In the first step of the reaction, the NaOH reacts with methanol in an acid base reaction. The products of this first step of the reaction are a very strong base, sodium methoxide, and water. In the second step, the sodium methoxide breaks the glycerine section from the fatty acid section. The separation of the glycerine portion leads to the formation of three methyl esters (the biodiesel) and glycerol. The NaOH is regenerated as a product in the reaction. The biodiesel and glycerol are immiscible and will separate to form two layers. The glycerol layer will also contain NaOH and excess methanol. The separation of the biodiesel and glycerol layer is fortuitous in that we can easily separate and isolate our biodiesel product from the remaining product mixture.

The following procedure is for synthesizing a biodiesel mini-batch from 100% pure unused vegetable oil. This method can easily be modified for other oils such as canola, olive, soybean peanut etc. You may bring an oil of your choice from home.

1. Warm up 10 mL of 100% pure vegetable oil to about 60°C in a 100 mL beaker. Warming the oil up is not necessary, but increases the reaction rate.
2. Transfer about 2 mL of sodium methoxide solution (be sure the solution is well mixed – should appear cloudy) to a 50 mL beaker with a magnetic stirrer. Stirring gently, add the warm oil. Cover with watch glass and turn up stirrer to position 7 or 8. Stir for about 30 minutes.
3. Transfer the contents of the beaker into a 15 mL plastic centrifuge tube. The mixture will separate into two different layers. The glycerol will sink to the bottom, and the methyl ester (biodiesel) will float to the top. Allow the mixture to sit for about 15 minutes, and then place it in a centrifuge and spin for another 5 minutes (don’t forget to counterbalance the centrifuge). If the layers have not separated continue to centrifuge for another 5 minutes.
4. Using a transfer pipet, carefully draw off the top layer of biodiesel. Make sure not to get glycerol (bottom darker layer) in the biodiesel.
5. Use the IR, NMR and GCMS to identify your products.

For the IR spectrum, your instructor will show you how to operate the machine. Look for presence of a carbonyl group and OH group (due to methanol or glycerol impurity).

For the NMR spectrum, add 3-4 drops of your sample to an NMR tube and then add 0.7 mL of CDCl3 (deuterochloroform, a common NMR solvent). On the library there is an NMR spectrum of pure vegetable oil. Compare your spectrum to this to determine if you produced biodiesel.

For the mass spectroscopy, place 4 mL of methylene chloride and 1 drop of your product into the special mass spec vial (provided by your instructor). Note the number on the vial. Cap and return the vial to your instructor. Your sample will be analyzed by the autosampler within the next two days.

ADI RIYADHI ( http://chemistrywan.blogspot.com )

TAHUKAH ANDA IV

Tahukah anda : Gas alam dapat disimpan dalam bentuk cairan dengan cara diberi tekanan tinggi. Gas alam dalam bentuk cair 600 kali volumenya lebih kecil dibandingkan dalam bentuk gas. Jadi dengan tempat yang sama dalam bentuk cairan, gas alam 600 kali lebih banyak dibandingkan dengan bentuk gas dengan volume yang sama.

Tahukah anda : Helium adalah salah satu unsur gas mulia yang digunakan untuk menggantikan udara pada pernafasan penyelam atau orang lain yang bekerja dibawah tekanan tinggi, dengan campuran helium 80 % dan Oksigen 20 %. Terlalu lama terkena udara yang dimampatkan dapat menimbulkan narkose nitrogen, yang salah satu efeknya adalah halusinasi, yang oleh penyelam dikenal sebagai pesona bawah laut, para penyelam yang terpesona demikian tak mampu memperhatikan tindakan-tindakan pengamanan dan mungkin akan tenggelam. Helium disarankan sebagai pengganti nitrogen karena helium kurang larut dalam darah dibandingkan nitrogen. Selagi penyelam kembali ke tekanan atmosfer, melarutnya gas nitrogen akan membentuk gelembung-gelembung gas yang sangat kecil dalam darah, yang menimbulkan “ tekukan” yang terasa nyeri dan berbahaya.

Tahukah anda : Natrium, kalium, rubidium dan sesium bereaksi sedemikian hebat dengan air pada temperatur kamar sehingga hidrogen yang dihasilkan dapat menyala oleh kalor yang dibebaskan. Reaksi dengan air semacam itu begitu hebat sehingga harus dilarutkan dengan hati-hati. Kalsium dan lithium bereaksi lebih lambat dengan air.

Tahukah anda : Tabel berkala bermanfaat secara mengagumkan bagi mereka yang mempelajari bangun atom dalam awal abad ini. Kegunaan tabel berkala yang terbesar ialah dalam membantu kita merumuskan dengan jelas reaksi dan sifat kimia.

TAHUKAH ANDA III

Tahukah anda : Protein jika dipanaskan diatas 500C atau dikenai asam atau basa kuat, protein akan kehilangan struktur tersiernya yang khas dan dapat membentuk koagulat yang tak larut misalnya putih telur. Putih telur bila dipanaskan atau diberi asam kuat atau basa kuat akan menggumpal.

Tahukah anda : Asam sulfat dapat digunakan sebagai bahan pendehidrasi yang kuat (penyerap air), mampu menyingkirkan air dari banyak senyawa organik (misalnya dalam membuat ahhibrida asam ).

Tahukah anda : Plastik merupakan suatu polimer carbon dengan rantai yang panjang, plastik dapat direngkah dengan menggunakan katalis menjadi fraksi yang lebih pendek lagi seperti fraksi bensin.

Tahukah anda : Sabun dapat bereaksi dengan ion logam seperti ion besi, ion kalsium, ion magnesium dan lainnya, sehingga sifat sabunnya berkurang, yaitu tidak dapat mengikat lemak.Oleh sebab itu sabun tidak cocok digunakan dengan menggunakan air sadah dan air yang tercemar ion logam seperti besi. Untuk air yang banyak mengandung ion logam sebaiknya digunakan ditergent.

Tahukah anda : cell bahan bakar hidrogen, menggunakan hidrogen sebagai anode dan oksigen sebagai katoda. Elektron dalam fuel cell berasal dari hidrogen yang mengalir dari anoda menuju katoda sehingga dihasilkan arus listrik. Oksigen bereaksi dengan hidrogen yang kekurangan elektron menghasilkan air. Cell bahan bakar hidrogen merupakan penghasil listrik yang rendah polusi karena produk akhirnya adalah air, yang bukan zat pencemar.

TAHUKAH ANDA II

Tahukah anda : Jika konsentrasi etilena (C2H4) dalam suatu buah dibiarkan bertumpuk, atau jika buah itu disemprot dengan etilena, proses pematangan akan lebih cepat. Hidrokarbon lain dengan ikatan ganda, seperti propena (C3H6) dan butena (C4H8), dan asetilena (C2H2) juga menunjukan efek pematangan. Diduga hidrokarbon ini merangsang dihasilkannya enzim yang mengendalikan proses pematangan. Oleh sebab itu kadang kala digunakan kalsium karbida (karbit) dalam mempercepat pematangan buah-buahan, sebab kalsium karbida bila bereaksi dengan air akan menghasilkan gas asetilen yang dapat membantu proses pematangan buah.

Tahukah anda : Diperkirakan bahwa mesin yang ada dapat diubah untuk bisa menggunakan metanol murni dengan biaya sekitar 100 dollar perkendaraan. Dibandingkan bensin, penggunaan metanol dalam suatu mesin uji standar menghasilkan karbon monoksida sepersepuluhnya, jadi penggunaan metanol sebagai bahan bakar lebih ramah lingkungan dibandingkan bensin.

Tahukah anda : Silica alumina banyak terdapat pada lempung atau tanah liat yang biasa digunakan dalam pembutan batu bata, silica alumina juga terdapat pada zeolit yang digunakan sebagai katalis.

Tahukah anda : Sejak zaman Belanda para petani kita sudah mengenal pupuk Z.A. (zwavelzuur amonium) yang tiada lain adalah amonium sulfat, (NH4)2 SO4. Pupuk Z.A. hanya mengandung 21 % berat nitrogen. Akan tetapi harganya lebih murah dari urea, serta dapat menyumbangkan unsur S (belerang) yang juga esensial bagi tumbuh-tumbuhan. Hanya penggunaan pupuk Z.A. yang terlalu banyak akan menyebabkan tanah bersifat asam.

Tahukah anda : Alkohol dapat bersifat sebagai asam. Alkohol mirip air dalam hal bersikap sebagai suatu basa dan menerima sebuah proton (menghasilkan suatu alkohol terprotonkan, ROH2+). Seperti air pula, suatu alkohol dapat bersikap sebagai asam dan melepaskan sebuah proton (menghasilkan ion alkoksida, RO-). Seperti air, alkohol adalah asam atau basa yang sangat lemah, untuk alkohol murni atau alkohol dalam air, kesetimbangan ionisasi terletak di sebelah kiri (di daerah alcohol takterionkan).Dalam larutan encer dalam air, alcohol mempunyai pKa yang kira-kira sama dengan pKa air. Namun dalam keadan murni (tak ada air) alkohol-alkohol jauh lebih lemah daripada air. Nilai pKa methanol murni sekitar 17, dan alkohol-alkohol lain lebih lemah lagi. Sebagai perbandingan untuk air murni pKa = 15,7 (bukan 14, yakni pKw).Satu alasan mengapa alkohol murni mempunyai keasaman yang lebih rendah adalah karena alkohol mempunyai tetapan dielektrik yang lebih rendah. Karena mereka kurang polar, alcohol kurang mampu mendukung ion dalam larutan daripada molekul air. Dalam larutan-air yang encer, alkohol mempunyai nilai pKa yang kira-kira sama seperti air.

TAHUKAH ANDA I

Tahukah anda : Karbon atau arang kayu yang biasa digunakan untuk memasak sate adalah media yang baik untuk memurnikan air dari pencemar logam seperti zat besi yang biasa mencemari air di perkotaan, karena arang kayu memiliki pori-pori yang mampu mengadsorpsi ion logam yang terdapat dalam air.

Tahukah anda : Sucralosa sebagai pemberi rasa manis pengganti gula, dibuat dari gula dan memiliki rasa manis 600 kali lipat dari gula biasa. Penggunaannya relatif aman karena tidak diabsorpsi oleh tubuh atau tidak diserap oleh tubuh, jadi hanya lewat saja kemudian dibuang lewat urin.

Tahukah anda : Pengolahan air minum dengan cara dimasak hanya cocok untuk air minum dari sumber yang belum tercemar, sedangkan untuk daerah perkotaan dan industri dimana airnya telah tercemar, pengolahan air minum dengan cara dimasak hanya dapat membunuh kuman tapi tidak menghilangkan bahan kimia berbahaya yang terdapat didalamnya, perlu pengolahan lebih lanjut agar air yang tercemar dapat dimunum, seperti dengan cara destilasi, adsorpsi, penukar ion atau menyaringnya dengan menggunakan membran semipermiable.

Tahukah anda : Mercury adalah logam yang berbentuk cair pada temperatur kamar, mercury akan menjadi padat bila diberi tekanan sebesar 7.640 atm atau 7,7 juta milibar.

Tahukah anda : Logam natriun dan kalium sangat mudah teroksidasi dan akan terbakar bila bereaksi dengan air aleh sebab itu untuk menyimpan logam natrium (sodium) dan kalium (potasium) dengan cara merendamnya didalam minyak tanah agar tidak teroksidasi, begitu pula dengan logam-logam lain agar tidak berkarat dilapisi dengan cet atau dilapisi dengan minyak tanah.

BASIC CHEMISTRY VII

BASIC CHEMISTRY VII

SCOPE OF THE OCTET RULE
It must be emphasized that the octet rule does not describe the electronic configuration of all compounds. The very existence of any compounds of the noble gases is evidence that the octet rule does not apply in all cases. Other examples of compounds that do not obey the octet rule are BF3, PF5, and SF6. But the octet rule does summarize, systematize, and explain the bonding in so many compounds that it is well worth learning and understanding. Compounds in which atoms attain the configuration of helium (the duets) are considered to obey the octet rule, despite the fact that they achieve only the duet characteristic of the complete first shell of electrons.

DISTINCTION BETWEEN IONIC AND COVALENT BONDING
The word bonding applies to any situation in which two or more atoms are held together in such close proximity that they form a characteristic species which has distinct properties and which can be represented by a chemical formula. In compounds consisting of ions, bonding results from the attractions between the oppositely charged ions. In such compounds in the solid state, each ion is surrounded on all sides by ions of the opposite charge. In a solid ionic compound, it is incorrect to speak of a bond between specific pairs of ions, and ionic compounds do not form molecules. In contrast, covalent bonding involves the sharing of electron pairs between two specific atoms, and it is possible to speak of a definite bond. For example, in molecules of HCl and CH4 there are one and four covalent bonds per molecule, respectively.

BASIC CHEMISTRY VII

BASIC CHEMISTRY VII

SCOPE OF THE OCTET RULE
It must be emphasized that the octet rule does not describe the electronic configuration of all compounds. The very existence of any compounds of the noble gases is evidence that the octet rule does not apply in all cases. Other examples of compounds that do not obey the octet rule are BF3, PF5, and SF6. But the octet rule does summarize, systematize, and explain the bonding in so many compounds that it is well worth learning and understanding. Compounds in which atoms attain the configuration of helium (the duets) are considered to obey the octet rule, despite the fact that they achieve only the duet characteristic of the complete first shell of electrons.

DISTINCTION BETWEEN IONIC AND COVALENT BONDING
The word bonding applies to any situation in which two or more atoms are held together in such close proximity that they form a characteristic species which has distinct properties and which can be represented by a chemical formula. In compounds consisting of ions, bonding results from the attractions between the oppositely charged ions. In such compounds in the solid state, each ion is surrounded on all sides by ions of the opposite charge. In a solid ionic compound, it is incorrect to speak of a bond between specific pairs of ions, and ionic compounds do not form molecules. In contrast, covalent bonding involves the sharing of electron pairs between two specific atoms, and it is possible to speak of a definite bond. For example, in molecules of HCl and CH4 there are one and four covalent bonds per molecule, respectively.

BASIC CHEMISTRY VI

BASIC CHEMISTRY VI

IONS
The electronic configuration of a potassium atom is

K : 2 8 8 1 ( 1s2 2s2 2p6 3s2 3p6 4s1 )

It is readily seen that if a potassium atom were to lose one electron, the resulting species would have the configuration

K+ : 2 8 8 0 ( 1s2 2s2 2p6 3s2 3p6 4s0 )

or more simply

K+ : 2 8 8 ( 1s2 2s2 2p6 3s2 3p6 )

The nucleus of a potassium atom contains 19 protons, and if there are only 18 electrons surrounding the nucleus after the atom has lost one electron, the atom will have a net charge of 1+. An atom (or group of atoms) that contains a net charge is called an ion. In chemical notation, an ion is represented by the symbol of the atom with the charge indicated as a superscript to the right. Thus, the potassium ion is written K+. Ions that have the electronic configurations of noble gases are rather stable. Note the very important differences between a potassium ion and an argon atom, the different nuclear charges and the net 1+ charge on K+. The K+ ion is not as stable as the Ar atom.


COVALENT BONDING
The element hydrogen exists in the form of diatomic molecules, H2. Since both hydrogen atoms are identical, they are not likely to have opposite charges. (Neither has more electron-attracting power than the other.) Each free hydrogen atom contains a single electron, and if the atoms are to achieve the same electronic configuration as atoms of helium, they must each acquire a second electron. If two hydrogen atoms are allowed to come sufficiently close to each other, their two electrons will effectively belong to both atoms. The positively charged hydrogen nuclei are attracted to the pair of electrons shared between them, and a bond is formed. The bond formed from the sharing of a pair of electrons (or more than one pair) between two atoms is called a covalent bond. The hydrogen molecule is more stable than two separate hydrogen atoms. By sharing a pair of electrons, each hydrogen atom acquires a configuration analogous to that of a helium atom. Other pairs of nonmetallic atoms share electrons in the same way.

BASIC CHEMISTRY V

BASIC CHEMISTRY V

CHEMICAL FORMULAS

Chemical formulas yield the following information:

1. Which elements are present
2. The ratio of the number of atoms of each element to the number of atoms of each other element
3. The number of atoms of each element per formula unit of compound
4. The fact that all the atoms represented are bonded together in some way

You cannot tell from a formula how many atoms of each element are present in a given sample of substance, because there might be a little or a lot of the substance present. The formula tells the ratio of atoms of each element to all the others, and the ratio of atoms of each element to formula units as a whole.

THE OCTET RULE
The elements helium, neon, argon, krypton, xenon, and radon, known as the noble gases, occur in nature as monatomic gases. Their atoms are not combined with atoms of other elements or with other atoms like themselves. The charge on the nucleus and the number of electrons in the valence shell determine the chemical properties of the atom. The electronic configurations of the noble gases (except for that of helium) correspond to a valence shell containing eight electrons, a very stable configuration called an octet. Atoms of other main group elements tend to react with other atoms in various ways to achieve the octet. The tendency to achieve an octet of electrons in the outermost shell is called the octet rule. If the outermost shell is the first shell, that is, if there is only one shell occupied, then the maximum number of electrons is two. A configuration of two electrons in the first shell, with no other shells occupied by electrons, is stable.

BASIC CHEMISTRY IV

BASIC CHEMISTRY IV

ATOMIC THEORY (John Dalton)
In 1804, John Dalton proposed the existence of atoms. He not only postulated that atoms exist, as had ancient Greek philosophers, but he also attributed to the atom certain properties. His postulates were as follows:

1. Elements are composed of indivisible particles, called atoms.
2. All atoms of a given element have the same mass, and the mass of an atom of a given element is different from the mass of an atom of any other element.
3. When elements combine to form a given compound, the atoms of one element combine with those of the other element(s) in a definite ratio to form molecules. Atoms are not destroyed in this process.
4. Atoms of two or more elements may combine in different ratios to form different compounds.
5. The most common ratio of atoms is 1:1, and where more than one compound of two or more elements exists, the most stable is the one with 1:1 ratio of atoms. (This postulate is incorrect.)

ATOMIC STRUCTURE
From 50 to 100 years after Dalton proposed his theory, various discoveries were made that show that the atom is not indivisible, but really is composed of parts. Natural radioactivity and the interaction of electricity with matter are two different types of evidence for this subatomic structure. The most important subatomic particles are Proton (+1) , Neutron (0), and Electron (-1), along with their most important properties. The protons and neutrons are found in a very tiny nucleus (plural, nuclei). The electrons are found outside the nucleus.

ISOTOPES
Atoms having the same number of protons but different numbers of neutrons are called isotopes of one another. The number of neutrons does not affect the chemical properties of the atoms appreciably, so all isotopes of a given element have essentially the same chemical properties. Different isotopes have different masses (contrary to Dalton’s second postulate) and different nuclear properties, however. The sum of the number of protons and the number of neutrons in the isotope is called the mass number of the isotope. Mass number is symbolized A. Isotopes are usually distinguished from one another by their mass numbers, given as a superscript before the chemical symbol for the element. Carbon-12 is an isotope of carbon with a symbol 12C.

PERIODIC TABLE
The periodic table is an extremely useful tabulation of the elements. It is constructed so that each vertical column contains elements that are chemically similar. The elements in the columns are called groups, or families. (Elements in some groups can be very similar to one another. Elements in other groups are less similar. For example, the elements of the first group resemble one another more than the elements of the fourth group from the end, headed by N.) Each row in the table is called a period. There are three distinct areas of the periodic table—the main group elements, the transition group elements, and the inner transition group elements

ELECTRONIC STRUCTURE
The arrangement of electrons in successive energy levels in the atom provides an explanation of the periodicity of the elements, as found in the periodic table. The charges on the nuclei of the atoms increase in a regular manner as the atomic number increases. Therefore, the number of electrons surrounding the nucleus increases also. The number and arrangement of the electrons in the outermost shell of an atom vary in a periodic manner. For example, all the elements in Group IA (H, Li, Na, K, Rb, Cs, Fr) corresponding to the elements that begin a new row or period, have electronic configurations with a single electron in the outermost shell, specifically an s subshell.

H = 1s1
Li = 1s2 2s1
Na = 1s2 2s2 2p6 3s1
K = 1s2 2s2 2p6 3s2 3p6 4s1
Rb = 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1
Cs = 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s1
Fr = 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f 14 5d10 6p6 7s1

The noble gases, located at the end of each period, have electronic configurations of the type ns2 np6, where n represents the number of the outermost shell. Also, n is the number of the period in the periodic table in which the element is found.

BASIC CHEMISTRY III

BASIC CHEMISTRY III

SUBSTANCES
There are two kinds of substances-elements and compounds. Elements are substances that cannot be broken down into simpler substances by ordinary chemical means. Elements cannot be made by the combination of simpler substances. There are slightly more than 100 elements, and every material object in the universe consists of one or more of these elements. Familiar substances that are elements include carbon, aluminum, iron, copper, gold, oxygen, and hydrogen.

COMPOUNDS
Compounds are substances consisting of two or more elements chemically combined in definite proportions by mass to give a material having a definite set of properties different from that of any of its constituent elements. For example, the compound water consists of 88.8% oxygen and 11.2% hydrogen by mass. The physical and chemical properties of water are distinctly different from those of both hydrogen and oxygen. For example, water is a liquid at room temperature and pressure, while the elements of which it is composed are gases under these same conditions. Chemically, water does not burn; hydrogen may burn explosively in oxygen (or air). Any sample of pure water, regardless of its source, has the same composition and the same properties.

MIXTURES
There are two kinds of mixtures-homogeneous mixtures and heterogeneous mixures. Homogeneous mixtures are also called solutions, and heterogeneous mixtures are sometimes simply called mixtures. In heterogeneous mixtures, it is possible to see differences in the sample merely by looking, although a microscope might be required. In contrast, homogeneous mixtures look the same throughout the sample, even under the best optical microscope.

BASIC CHEMISTRY II

BASIC CHEMISTRY II

PROPERTIES
Every substance has certain characteristics that distinguish it from other substances and that may be used to establish that two specimens are the same substance or different substances. Those characteristics that serve to distinguish and identify a specimen of matter are called the properties of the substance. For example, water may be distinguished easily from iron or gold, and-although this may appear to be more difficult-iron may readily be distinguished from gold by means of the different properties of the metals.

PHYSICAL PROPERTIES
The properties related to the state (gas, liquid, or solid) or appearance of a sample are called physical properties. Some commonly known physical properties are density, state at room temperature, color, hardness, melting point, and boiling point. The physical properties of a sample can usually be determined without changing its composition. Many physical properties can be measured and described in numerical terms, and comparison of such properties is often the best way to distinguish one substance from another.

CHEMICAL PROPERTIES
A chemical reaction is achange in which at least one substance changes its composition and its set of properties. The characteristic ways in which a substance undergoes chemical reaction or fails to undergo chemical reaction are called its chemical properties. Examples of chemical properties are flammability, rust resistance, reactivity, and biodegradability.

BASIC CHEMISTRY I

BASIC CHEMISTRY I

ELEMENT
An element is a substance that can not be broken down into simpler substances by ordinary means. A few more than 100 elements and the many combinations of these elements-compounds or mixtures-account for all the materials of the world. Exploration of the moon has provided direct evidence that the earth’s satellite is composed of the same elements as those on earth. Indirect evidence, in the form of light received from the sun and stars, confirms the fact that the same elements make up the entire universe. Before it was discovered on the earth, helium (from the Greek helios, meaning “sun”) was discovered in the sun by the characteristic light it emits.

MATTER AND ENERGY
Chemistry focuses on the study of matter, including its composition, its properties, its structure, the changes that it undergoes, and the laws governing those changes. Matter is anything that has mass and occupies space. Any material object, no matter how large or small, is composed of matter. Incontrast, light, heat, and sound Are forms of energy. Energy is the ability to produce change. Whenever a change of any kind occurs, energy is
involved; and whenever any form of energy is changed to another form, it is evidence that a change of some kind is occurring or has occurred.