Chemistry Notes PDF

Summary

These notes cover fundamental concepts in chemistry, including the nature and properties of different states of matter (solid, liquid, gas, plasma, Bose-Einstein Condensate).

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In depth lessons In depth lessons.................................................1 1.1 Nature and State of Matter.....................2 States of Matter................................. 2 1.2 Properties of Matter................................. 3 Physical Propert...

In depth lessons In depth lessons.................................................1 1.1 Nature and State of Matter.....................2 States of Matter................................. 2 1.2 Properties of Matter................................. 3 Physical Properties............................3 Chemical Properties......................... 3 2.1 Classifications of Matter......................... 4 Pure substance................................... 4 Mixtures............................................... 4 2.2 Basic Separation Techniques................ 5 3.1 Fundamental Laws of Chemistry and Dalton's Atomic Theory................................. 8 3.2 Atomic Number, Mass Number, Isotopes, Molecules and Ions.......................9 4 Empirical and Molecular Formula.........11 4.2 Formula Writing and Naming of Metal-Nonmetal...............................................11 Shortcut/Reviewer/Keywords................. 12 1.1 Nature and State of Matter.......12 States of Matter................................ 12 1.2 Properties of a Matter...............12 1.2 Properties of Matter.................. 13 2.1 Classification of Matter.............13 1.1 Nature and State of Matter c. Slight expansion during heating Five Main Principles of Leucippus and d. Can be compressed to a Democritus theory: negotiable extent - All matter is made up of atoms that e. Medium density are too tiny to be seen by the f. Particles are close to one naked eyes. They cannot be broken another and slide/move down into smaller portions. All past one another forms of Matter result from the 3. Gas coming together or breaking apart a. No definite shape, no of atoms. definite volume - Atoms are in constant motion b. Can be compressed or around an empty space called void. expanded as pressure is - Atoms are completely solid. increased or decreased - Atoms are uniform, with no c. Great expansion during internal structure. (it does have a heating structure, but this is an outdated d. Low density concept from leu and demo) e. Particles are far apart, move - Atoms come in different shapes and randomly/freely sizes. 4. Plasma States of Matter a. Formed by heating and Matter - Anything that occupies space ionizing a gas and has mass b. Made up of groups of negatively and positively Matter In different forms: charged particles. 1. Solid c. Observed in ionized gas, a. Definite shape and volume aurora borealis, lightning b. Cannot be compressed by a and comet moderately high pressure 5. Bose- Einstein Condensate c. High density a. Produced when a cloud of d. Slight expansion during bosons is cooled to a heating temperatures very close to e. Particles are in fixed absolute zero such that position and wiggle/vibrate large fraction of the bosons in their position condense 2. Liquid b. include superfluids like cold a. No definite shape; takes the liquid helium, and shape of the container superconductors like b. Has definite volume nucleons inside a neutron star. 1.2 Properties of Matter - depend on the amount of matter present or being tested. If there is a change in the amount of matter, these properties will change too volume mass length shape Chemical Properties - involved in the transformation of Physical Properties substances into other materials - Perceived by the senses that can which possess a completely be observed, measured, and tested different structure and without changing the composition composition from the original. of the matter. Chemical properties include flammability, Includes phase (solid, liquid or gas), color, toxicity, combustibility, reactivity and solubility, density, melting, shape, melting oxidation. point, boiling point, hardness, volume, mass, and length. 1. Flammability is the ability to catch fire and burn easily at normal Example: Gold is yellow in color. working temperature. The act of observing the color of gold 2. Toxicity is how dangerous a does not change its composition. The chemical is to organisms and to same is true in observing its physical state the environment. as a solid and in noting its ability to 3. Combustibility is the ability to be conduct electricity burnt at temperatures that are above normal working 2 classification of Physical properties: temperature. 1. Intensive Properties 4. Reactivity is a measure of how - do not depend on the amount of likely a sample is to participate in a matter present or being measured. chemical reaction under a variety if there is a change in the amount of conditions. Example: Iron nails of matter, these properties will become dull when exposed to air remain the same. 5. Oxidation is the resistance of a substance to change in the color Boiling point Density presence of oxygen. hardness Melting point 2. Extensive Properties 2.1 Classifications of Matter - Brittle - Poor conductor - Good insulators - Exists in 3 states - Have low densities 2. Compound - composed of 2 or more kinds of atoms that are chemically bonded in fixed proportion Classification of compound: 2.1 Acid Matter can be classified as pure - Donates H+ ions in an aqueous substance or a mixture. solution - Sour Pure substance - Blue litmus paper to red - Contains one type of particle, and - E.g. vinegar, citrus fruits has the same element all 2.2 Salts throughout - Formed when acid and base reacts Classification of pure substance: - This reaction where salt and water 1. Element - composed of only one are formed is called neutralization kind of atom - E.g. are table salt, calcium Classification of elements: chloride 1.1 Metal 2.3 Base - Lustrous - Accepts H+ ions in an aqueous - Malleable solution tastes - Ductile - bitter/ slippery to touch - Good conductors of heat and - red litmus paper to blue electricity - E.g. soap, ammonia, detergent - Mostly hard powders, baking soda - High densities 1.2 Metalloid Mixtures - Have both the properties of metal - Two or more substances mixed but and non-metal not chemically combined - Form staircase pattern in periodic Classification of Mixtures: table of elements 1. Homogeneous - Ex. boron, silicon, germanium, - Uniform composition/solution arsenic etc. 2. Heterogenous 1.3 Nonmetal - Has 2 or more phases - Dull in appearance a. Colloid - Particles of solution>particles of Knowing the physical properties, one can colloid>particles of suspension select a method on how to separate the - Particles are evenly distributed in components of a mixture. the mixture - Particles does not settle 1. Filtration - Used to separate water- soluble from insoluble components - Requires filtering medium (cheesecloth or filter paper) b. Suspension - Residue are solid components that - Particles are biggen than those of remains in the filtering medium colloids - Filtrate is the clear liquid collected - Contains solid particles that settle - E.g. sand and water, food and beverages having a "shake well before using" notice 2. Sedimentation - Heavy suspended particles are allowed to settle at the bottom of 2.2 Basic Separation the container Techniques - Followed by decantation 3. Decantation - A process of separating a solid from a liquid, by pouring off the liquid after sedimentation - Example is sand and water Methods of Separating Mixtures 4. Dissolution 7. Crystallization - Mixture of soluble and insoluble - method to separate a soluble solid solid substances can be separated from its solution based on the by using an appropriate solvent different solubility of solid in water - the solvent chosen will either at 25 degrees Celsius. Generally, dissolve any of the solid the solubility of most solids substances in the mixture. The one increases as the temperature that is not dissolved in the chosen increases. Therefore, when a solvent can be removed by so-called saturated solution is filtration. cooled, the solubility of the solid - Example is salt and sand substances will decrease and the 6. Distillation excess solid will crystallize. - liquid is converted into a vapor by - (in short, the substance will boiling. vapor is converted back to crystallize once the solvent can no liquid by cooling longer hold the solute coz of the - Simple distillation is used if the temp yeh) impurities are not volatile(don’t 8. Chromatography easily turn into vapor) and the - A process utilizing the strategy liquid compound does not that lets the mixture flow over a decompose at its boiling point material that retains some - Fractional distillation is used to component more so different separate two or more immiscible components flow over the material liquids with different boiling at different speeds. points. - It has two components, the mobile phase and the stationary phase. 9. Centrifugation - A process of separating mixtures by applying centripetal force to a mixture using a centrifuge machine (ikot-ikot toh) 10. Evaporation - This process involves the application of heat to the solution to allow the solvent to evaporate leaving behind the solid component as a residue. 11. Use of Magnet - Separation of metallic and non-metallic substances 12. Use of Separatory Funnel - Used to facilitate the separation of liquid- liquid mixture that did not mix. 3.1 Fundamental Laws of Chemistry and Dalton's Law of Definite Proportion Atomic Theory Joseph Proust (1754-1826) formulated the Law of Conservative of Mass law of definite proportions (also called the - Formulated by Antoine Lavoiser Law of Constant Composition or Proust's (1743-1794) as a result of his Law). This law states that if a compound is combustion experiment. [in which he broken down into its constituent observed that the mass of his original substance—a glass vessel, tin, and air—was equal to the mass of the produced substance—the elements, the masses of the constituents ] glass vessel, “tin calx”, and the remaining air. will always have the same proportions, regardless of the quantity or source of the "the atoms of an object cannot be created original substance. The illustration below or destroyed, but can be moved around and show this law in a given scenario. be changed into different particles." When a chemical reaction rearranges atoms into a new product, the mass of the reactants (chemicals before the chemical reaction) is the same as the mass of the products (the new chemicals made). More If 1 simply, whatever you do, you will still have the same amount of stuff (however, certain nuclear reactions like fusion and fission can convert a small part of the mass into energy. gram of A reacts with 8 grams of B, then The law of conservation of mass states by the Law of Definite Proportions, 2 that the total mass present before a grams of A must react with 16 grams of B. chemical reaction is the same as the total If 1 gram of A reacts with 8 grams of B, mass present after the chemical reaction; then by the Law of Conservation of Mass, in other words, mass is conserved. they must produce 9 grams of C. Similarly, when 2 grams of A react with 16 grams of B, they must produce 18 grams of C. Law of Multiple Proportion combines with unit mass (1 g) of nitrogen. There are diverse elements that can react Line is obtained by dividing the figures to form more than one compound. In the previous line by the smallest O:N ratio such situations, this law states that the in the line above, which is the one for weights of one element that combine with N2O. Note that just as the law of multiple a fixed weight of another of these proportions says, the weight of oxygen elements are integer multiples of one that combines with unit weight of another. In the example below, nitrogen nitrogen work out to small integers. forms a very large number of oxides, five of which are shown in the image. Dalton’s Atomic Theory Dalton's Theory was a powerful development as it explained the three fundamental laws and recognized a workable distinction between the fundamental particle of an element (atom) and that of a compound (molecule). Four postulates are involved in Dalton's Atomic Theory: All matter consists of tiny, indivisible particles called atoms. Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements. Atoms of different elements may combine with each other in Linealtshows the ratio of the relative a fixed, simple, whole number ratios to weights of the two elements in each form compound atoms. In a chemical compound. These ratios were calculated reaction, atoms are rearranged to form by simply taking the molar mass of each new compounds; they are not created, element, and multiplying by the number destroyed nor changed into atoms of of atoms of that element per mole of the different element. compound. Thus for NO2, we have (1 × 14) : (2 × 16) = 13:32. (These numbers were not 3.2 Atomic Number, Mass known in the early days of Chemistry Number, Isotopes, Molecules because atomic weights (i.e., molar masses) of most elements were not and Ions reliably known.) The numbers in Linealtare just the mass ratios of O:N, Atomic numbers, AMss number and found by dividing the corresponding Isotopes ratios in line 1. But someone who depends solely on experiment would work these out by finding the mass of O that Molecules are the fundamental building blocks of life. Water for example is very essential that life on Earth would not exist without it. Proteins that make up all The nuclei of an atom contain neutrons functions, regulations and structure in as well as protons. Unlike protons, the the body are also comprise of molecules. number of neutrons is not absolutely So, in order for us to understand life itself fixed for most elements. Atoms that we need a thorough knowledge of how have the same number of protons, and atoms combine to form molecules and in hence the same atomic number, but turn form life. Of all the elements, only different numbers of neutrons are called the six noble gases in Group 8A of the isotopes. All isotopes of an element periodic table (He, Ne, Ar, Kr, Xe, and Rn) have the same number of protons and exist in nature as single atoms. Most electrons, which means they exhibit the matter is composed of molecules or ions same chemistry. Because different formed by atoms. A molecule is an isotopes of the same element haves aggregate of at least two atoms in a different number of neutrons, each of definite arrangement held together by these isotopes will have a different attractive forces (also called chemical mass number (A), which is the sum of bonds). A molecule may contain atoms of the number of protons and the number the same element or atoms of two or of neutrons in the nucleus of an atom. more elements joined in a fixed ratio, in accordance with the law of definite mass number = number of protons + proportions stated. Thus, a molecule is number of neutrons not necessarily a compound, which, by definition, is made up of two or more elements. Hydrogen gas, for example, is a pure element, but it consists of molecules made up of two H atoms each. Water, on the other hand, is a molecular compound that contains hydrogen and oxygen in a ratio of two H atoms and one O atom. Like atoms, molecules are electrically neutral. An ion is an atom or a group of atoms that has a net positive or negative charge. The number of positively charged shows the actual number of atoms of each protons in the nucleus of an atom element in the smallest unit of a remains the same during ordinary substance. Example: H2O2 This formula chemical changes (called chemical indicates that each hydrogen peroxide reactions), but negatively charged molecule consists of two hydrogen atoms electrons may be lost or gained. The loss and two oxygen atoms. The ratio of of one or more electrons from a neutral hydrogen atoms to oxygen atoms in this atom results in a cation, an ion with a net molecule is 2:2 or 1:1. positive charge. For example, a sodium atom (Na) can readily lose an electron to become a sodium cation, which is 4.2 Formula Writing and represented by Na1: nacl On the other hand, an anion is an ion whose net charge Naming of Metal-Nonmetal is negative due to an increase in the number of electrons. A chlorine atom (Cl), Atomic numbers, AMss number and for instance, can gain an electron to Isotopes become the chloride ion Cl2: cation 4 Empirical and Molecular Formula Chemical formulas are shorthand symbols for compounds. Types of Formulas 1. Empirical Formula - Ismplest formula of a compound reflects the simplest ratios of atoms in the compound - Tells us which elements are present and the simplest whole number ratio of their atoms, but not necessarily the actual number of atoms in a given molecule - HO 2. Molecular Formula Based on the actual number of atoms that comprise a molecule of that compound. It Shortcut/Reviewer/Keywords Low density Great expansion during heating Move randomly/freely 1.1 Nature and State of Matter 4. Plasma Five Main Principles of Leucippus and Formed by heating and ionizing Democritus theory: gas 1. All matter is made up of atoms Made up of groups of negatively 2. Atoms are in constant motion and positively charged particles. around void Observed in ionized gas, aurora 3. Atoms are solid borealis, lightning and comet 4. Atoms are uniform 5. Bose- Einstein Condensate 5. Atoms come in different shapes Produced when a cloud of bosons and sizes is cooled to a temperatures very close to absolute zero such that States of Matter large fraction of the bosons Matter - anything that occupies space condense and has mass include superfluids like cold liquid helium, and superconductors like Matter in different forms: nucleons inside a neutron star. 1. Solid Definite shape and volume High density 1.2 Properties of a Matter Cannot be compressed by a 1. Physical Properties moderately high pressure - Can be observed, measured, and Slight expansion during heating tested Particles are in fixed position a. Intensive properties Vibrates in their position - Change in the amount of matter 2. Liquid does not change the property No definite shape, has definite - Color, hardness, density, boiling volume and melting point Medium density b. Extensive properties Can be compressed to a negotiable - Change in the amount of matter extent does change the property Slight expansion during heating - volume , length, mass, shape Slides past one another 2. Chemical properties 3. Gas - transformation of substances into No definite shape and volume other materials which possess a Can be compressed or expanded completely different structure as pressure is increased or a. Flammability - easily burnt decreased b. Toxicity - dangerous chemical - Mass is conserved. c. Combustibility - burnt at high temp Law of Definite Proportion d. Reactivity - how likely to “If a compound is broken down into its participate in a chem reaction constituent elements, the masses of the e. Oxidation - change in the constituents will always have the same presence of oxygen proportions, regardless of the quantity or source of the original substance.” volume tells you how much space an object takes up, mass tells you how much matter - By Joseph Proust it contains, and density tells you how tightly that matter is packed within the Law of Multiple Proportion volume “the weights of one element that combine with a fixed weight of another of these Flammable: Imagine a matchstick. It elements are integer multiples of one catches fire easily when struck. another” (flammable, therefore combustible) Combustible: Think of a log of wood. It 3.3 needs to be heated for a while before it Law of Conservation of Mass starts burning. (its combustible but not Antoine Lavoisier and the Origin of … flammable) 2.1 Classification of Matter Read it as it is 3.3 Fundamental laws of chemistry: Law of Conservation of Mass “The atoms of an object cannot be created nor destroyed, but can be moved around and be changed into different particles.” - By Antoine Lavoisier as a result of his combustion experiment. - The mass of the reactants is the same as the mass of the products.

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