genchem reviewer_20240929_122527_0000_240929_135822.pdf

STEM 004: GENERAL CHEMISTRY 1st Semester / Finals Reviewer LESSON 1 Matter & E...

STEM 004: GENERAL CHEMISTRY 1st Semester / Finals Reviewer LESSON 1 Matter & Energy Page 1 MATTER & ENERGY Particle Arrangement Responsible for all the transformation that undergoes STATE OF MATTER SHAPE VOLUME HEAT EXPANSION DENSITY example. SOLID Definite Definite Slight Expansion High Density LIQUID Indefinite Definite Slight Expansion Medium Density (solid water - ice) (heat energy) (liquid water) GAS Indefinite Indefinite High Expansion Low Density Question: Can matter changer its phase from one phase to another? YES MATTER PHASE CHANGE Anything that has mass & volume. Mass - amount of substance a change from one state of matter to another. Volume - amount of space occupied phase changes are physical changes because they do not affect the chemical make up of a substance. Physical & Chemical Change GAS N O I EV AT CO PHYSICAL CHANGE CHEMICAL CHANGE ON AP SUBLIM ND ORATION I SIT the substance is changed in the substance is changed in EN DEPO appearance, state or properties, but appearance & composition, resulting SATION not in composition to create one or more new substances. example. 1. Cutting papers example. SOLID M EL 2. Melting ice 1. Burning of papers TIN G 2. Rusting of metals LIQUID FREE IN G Z ORIGIN OF MATTER THE FOURTH AND FIFTH STATE OF MATTER 4 PLASMA plasma are ionized gases (undergo ionization) plasma are like gases. The only difference is ORGANIC MATTER INORGANIC MATTER that the particles of plasma are electrically charged. 5 BOSE-EINSTEIN (living things) (non-living things) Contains C-H bond Carbon dioxide is an inorganic matter CONDENSATE cloud of bosons (a type of elementary particle matter) is cooled to temperatures very close to absolute zero (T=0 K). FUNDAMENTAL STATES OF MATTER at absolute zero temperature, the particles stop moving, therefore nothing can be colder than this temperature. Main states/phase of matter are in such conditions, large fraction of bosons SOLID, LIQUID, GAS. condense or fall into the lowest quantum stats. Solid - particles are tightly packed together. - very compressed PROPERTIES OF MATTER properties = characteristics - fixed position - cannot move/slide past each other can be observed and measured, such as an object's density, color, mass, volume, length, etc. Liquid - particles are in close contact to each other. - not rigidly/orderly - can slide past each other to move freely Physical & Chemical Properties Gas - particles are well seperated with no regular arrangement. CHEMICAL PROPERTIES PHYSICAL PROPERTIES - can move freely - can expand to fill any volume can be observed with an can be observed by the - easily compressed into a smaller volume when pressure accompanying change. senses w/o changing the increase. composition. ISKA STEM 004 MS. NIZA  CHEMICAL PROPERTIES HOMOGENEOUS HETEROGENEOUS 1. Combustibility - Does the material burn? Does it uniform composition non-uniform composition support combustion? particles are well mixed components can be 2. Stability - Does the substance decompose easily or throughly mingled. physically identified not or with difficulty? exists in single phase EVENLY distributed in a same properties & sample. 3. Relative Activity - Is the material more or less sometimes form a layer active than other members of its chemical family? composition 4. Response to test reactions - Does it react to test substances like litmus paper? SEPERATING TECHNIQUES 5. Ionization - To what degree does it break into charged particles called ions when in solution Magnetic Seperation - seperate solids with water. Filtration - lets the liquid particles through, but traps the solid particles. EXTENSIVE PROPERTIES Distillation - the separation of a mixture of liquids based depend on how much matter (amount of matter) is being on the physical property of boiling point. considered. will change if the amount of matter changes Evaporation - Vaporizing a liquid and leaving the dissolved solid(s) behind. Used to separate INTENSIVE PROPERTIES salt solutions. do not depend on how much matter is being considered will not change if the amount of matter changes Centrifugation - applying centripetal force to a mixture using a centrifuge machine. Circular motion helps denser components sink to the bottom faster. CLASSIFICATION OF MATTER Crystallization - a method to separate a soluble Pure Substance solid from its solution based from the has only one component different solubility of solid in water unchanging/specific composition at 25 degree Celsius. cannot be broken down through Chromatography - A process utilizing the strategy that physical means. lets the mixture flow over a material that ELEMENT COMPOUND retains some component more so different components flow over the material at different speeds. It has simplest type of matter two or more elements two composed of only one combined chemically in components; the mobile phase and atom different proportions. the cannot be changed in held together by a force stationary phase. simpler form of matter by attraction (Chemical any chemical reactions. bond) Mixture combination of two or more substances that are physically combined. composed of different types of atoms/molecules that are not chemically bonded. can be seperated by physically means LESSON 1 Matter & Energy Page 2 ISKA STEM 004 MS. NIZA  LESSON 2 The Periodic Table & Periodic Trends Page 3 PERIODIC TABLE a tabular display of chemical elements Noble Gases 4 PEOPLE ARRANGED THE PERIODIC TABLE: - colorless gases, unreactive Johann Dobereiner - a german chemist Boron Family - have 3 valence electrons - known for triad - arranged the elements for 3 times Carbon Family - have 4 valence electrons Li 6.9 - contains the three types of elements Na 22.9 Nitrogen Family K 39.0 - have 5 valence electrons John Newlands - an english chemist - contains the three types of elements - known for atomic mass & "law of octaves" Oxygen Family Dmitri Mendeleev - father of periodic table - have 6 valence electrons Henri Moseley - established that each elements has a unique Halogen Family atomic number. - have 7 valence electrons - most reactive non-metals What's inside the box? - never found free in nature atomic number PERIOD horizontal row of elements elements in a period are not alike in properties. element symbol first element in a period is always an extremely active solid. The last element in a period, is always an inactive gas. element name atomic mass PERIODIC TRENDS Atomic Radius - total distance from an atom's nucleus to the outermost 2 PARTS OF PERIODIC TABLE orbital of electron. REPRESENTATIVE TRANSITION ELEMENTS ELEMENTS (group A) (group B) largely predictable less predictable same properties 3 MAIN TYPES OF ELEMENTS Metals - good conductors/solid Non-metal - poor conductors/gaseous at room temperature Metalloids - semi conductors/has the characteristic of non-metal & metal. Ionization Energy - the quantity of energy required to remove an electron FAMILY OR GROUP from the gaseous atom or ion-form a positive ion. column of elements elements in each family have similar but not identical properties. Ionic Radius - size of an ion have the same number of valence 1) Cation 2) Anion (TWO TYPES OF ION) Alkanine Earth Metals Cation - Positive, loss of e- (smaller than parent atom) - reactive metals that combined with non-metals Anion - Negative, gain of e- (larger than parent atom) - have 2 valence electrons Alkali Metals - found in first column - have 1 valence electron - most reactive metals Rare Earth Elements - 30 rare elements (composed of lanthanide & actinide series) Transition Metals - elements in group 3-12 - less reactive metals - good conductors Hydrogen - in a class of its own - only needs 2 electrons to fill up its valence shell ISKA STEM 004 MS. NIZA  LESSON 2 The Periodic Table & Periodic Trends Page 4 Electron Affinity - a measure of how much an atom can attract an electron. Electronegativity - it is the measure of the ability of an atom in a bond to attract electrons to itself. LESSON 3 Atoms, Molecules, and Ions Page 4 POSTULATES OF DALTON'S ATOMIC THEORY Everything is composed of atoms, which are the indivisible building blocks of matter and cannot be destroyed Atoms of a given element are identical in mass and chemical properties. Atoms of different elements have different mass and chemical properties. Compounds are produced through different whole-number combinations of atoms. A chemical reaction results in the rearrangement of atoms in the reactant and produce compounds. LAW'S OF MATTER most of the space in the atom is empty positively charged particles occupies a small space at the center Law of Conservation of Mass - mass is neither created nor destroyed of an atom. in a chemical reaction. there's a positively charge center in an atom called nucleus. The positively charged particle is called proton. Law of Definite Composition - different samples of the same Ernest Rutherford compound always contain its constituent elements in the same there is a neutrally charged particle inside an atom. proportion by mass. this neutrally charged particle is about the same weight as Law of Multiple Proportion - if two elements can combine to form protons more than one compound, the masses the neutrally charged particle is called neutron. of one element that combine with a fixed mass of the other element are in James Chadwick ratios of small whole numbers. Atomic Number cathode ray must be made of particles that are negatively Number of protons = Number of electrons charged. Number of electrons determine the combining capacity or valency of atoms have tiny, negatively charged particles inside them. an atom Thomson called these particles corpuscles, Later they were Number of electrons determine the reactivity of named electrons. an atom. J.J Thompson Atomic Mass Total number of protons and neutrons of an atom. Isotopes observe the presence of a positively charged particles. atoms of the same element that have the same number of protons but different numbers of neutrons. Ions is an atom or group of atoms that has an electrical charge, either a Eugen Goldstein positive charge or a negative charge. ISKA STEM 004 MS. NIZA  LESSON 4 Mole Concept, Chemical Reaction, and Stoichiometry Page 5 Atomic Mass Mass of an atom. Number of protons and neutrons inside the nucleus of an atom. Atomic Mass Unit or amu. This is specific to a particular isotope of a particular atom. AVOGADRO'S NUMBER a constant used to quantify the number of particles of an element (atoms, ions) or compound (molecules, formula units). Named in honor of the Italian scientist Amadeo Avogadro (1776-1856). Mole Molecular Mass A term used to collectively refer to the quantity ofparticles. Molecular mass is a number equal to the sum of the 602 hexilion of things atomic masses of the atoms in a molecule Symbol: mol Molecular mass is a dimensionless quantity, but it is given the unit amu (atomic mass unit). Molar Mass The sum of the total mass in grams of all the atoms that make up 1 mole of a particular molecule. The unit used to measure is grams per mole SAMPLE PROBLEMS ISKA STEM 004 MS. NIZA