STEM 7 - MIDTERMS (UPDATED) -2.pdf

MATTERS AND ITS PROPERTIES ○ This describes its "potential" to undergo some chemical change or reaction by virtue of its PARTICULATE NATURE OF MATTER...

MATTERS AND ITS PROPERTIES ○ This describes its "potential" to undergo some chemical change or reaction by virtue of its PARTICULATE NATURE OF MATTER composition. What elements, electrons, and ○ Matter is anything that occupies space and has mass bonding are present to give the potential for ○ Mass is a measure of the quantity of matter, often chemical change. reported in units of grams. ○ Chemical change results in one or more ○ The interaction of mass with gravity creates weight, substances of entirely different composition which can be measured on a scale or balance from the original substances. ○ All matter is made up of very small tiny discrete ○ EXAMPLES OF CHEMICAL CHANGE: particles and is a complex of extremely small particles ○ Milk turns sour and liquid droplets. ○ Digestion ○ Particles are very small in size. ○ Photosynthesis ○ Particles are continuously moving. ○ Rusting ○ Particles have space in between them and attract each Physical properties other. ○ Properties that can be observed or measured PARTICLE (OR KINETIC) THEORY OF MATTER: WITHOUT changing the composition of ○ All matter is formed of tiny particles. matter. ○ The particles are constantly randomly moving about. ○ TWO TYPES OF PHYSICAL PROPERTIES ○ The particles can be arranged regularly or randomly. ○ Intensive physical property ○ The particles are held together by weak or strong A property that will be the forces. same regardless of the ○ As temperature increases, the particles move faster. amount of matter. 3 STATES OF MATTER Density ○ Solid Temperature ○ Has a fixed shape Colour ○ described as a solid if it can hold its own Melting and boiling point. shape and is hard to compress (Macroscopic ○ Extensive Physical Property view). A property that will change if ○ Solids are tightly packed, usually in a regular the amount of matter pattern. (Microscopic view) changes. ○ Liquid Mass ○ No fixed shape Volume ○ A liquid will take on the shape of the Length container it is being held in. (Macroscopic view) Shape ○ The molecules are close together with no regular arrangement and have the ability to WAYS CLASSIFYING OF MATTER move around and slide past each other. (Microscopic view) Pure substance ○ Gaseous (Gas) ○ Matter that always has the same chemical ○ No fixed shape composition, no matter what their origin. ○ Much more spread out than in solids or ○ Has the same composition throughout and liquids, and the atoms collide randomly with from sample to sample. one another. A gas will fill any container, but if ○ Matter having an invariant chemical the container is not sealed, the gas will escape. composition and distinct properties. ○ Plasma ○ Substances that are made up of only one kind ○ Electrically charged gas of particle and have a fixed or constant ○ No definite volume and shape structure. ○ Fermionic condensate (Fermi-Dirac condensate) ○ Superfluid phase formed by fermionic particles Mixture at low temperatures. ○ Consists of two or more pure substances and may vary in ○ Formed using fermions instead of bosons. composition ○ Bose-Einstein condensate (BEC) 2 TYPES OF PURE SUBSTANCES ○ A state of matter in which separate atoms or Element subatomic particles, cooled to near absolute Fundamental substance; CANNOT be broken down into zero. simpler substances, even by chemical reaction. ○ Uses Bosons ○ Ex: hydrogen, chlorine, sodium Are classified into two main categories: metals and PHYSICAL AND CHEMICAL PROPERTIES: non-metals Chemical properties  ○ Metals can be distinguished from non-metals 1. All matter is composed of exceedingly small, by luster, thermal conductivity, and electrical indivisible particles, called atoms conductivity. 2. All atoms of a given element are identical both in mass ○ Examples of Metals are Copper, Aluminum, and in chemical properties. However, atoms of different Iron, etc. elements have different masses and different chemical ○ Examples of non-metals are Carbon, Chlorine, properties. Sulfur, etc. 3. Atoms are not created or destroyed in chemical Compound reactions Substance composed of TWO or more elements in 4. Atoms combine in simple, fixed, whole-number ratios definite proportions; CAN BE separated into simpler to form compounds substances and elements ONLY by chemical methods Law of conservation of mass (Anton Lavoisier) 2 TYPES OF MIXTURES - Published in 1787, this experiment showed that no Homogeneous measurable change in mass occurs during a ○ Mixture having a uniform composition and chemical reaction. The mass of the products of a properties throughout (also called a solution) reaction always equal the mass of the reacting ○ Ex. powdered juice, water and paint substances Heterogeneous Law of definite proportions ○ Mixture not uniform in composition and - Published between 1797 and 1804, this law states that all properties throughout (cannot be mixed or samples of the same compound always contain the same turned into a solution) proportions by mass of the component elements ○ Ex. Oil and water, ice cube in a drink. 3 SUBATOMIC PARTICLES Electrons (J.J. Thomson 1897) METHODS OF SEPARATING MIXTURES - A negatively charged subatomic particle - Cathode-ray experiment Chromatography Protons Separation of a mixture by passing it in solution or - A positively charged subatomic particle suspension, or as a vapor (as in gas chromatography) - Has a charge equal in magnitude to the electron but Evaporation in opposite sign is a technique used to separate out homogeneous Neutrons mixtures that contain one or more dissolved salts. - Is an uncharged particle in the nucleus of the atom Usually a solution of a solvent and a soluble solid. - In 1932, Ernest Rutherford and James Chadwick that Solution is heated until the organic solvent evaporates proved the existence of the neutron where it turns into a gas. MOLECULES AND IONS Distillation Separation technique used to separate components of a Molecules liquid mixture by a process of heating and cooling, Are neutral particles made of two or more atoms which exploits the differences in the volatility of each bonded together. of the components. Group of two or more atoms held together by Filtration attractive forces known as chemical bonds. Separation technique used to separate the components Ions of a mixture containing an undissolved solid in a An atom or group of atoms that has an electric liquid. charge. Cation ATOMS, MOLECULES, AND IONS An atom or group of atoms that has a positive charge. Democritus (Greek Philospher) Believed that there was a limit to how far a matter STOICHIOMETRY could be broken into smaller particles He gave the smallest components of matter the name Atomic Mass atomos (atom in English) meaning “unbreakable” It is the average mass of the atoms in an element, John Dalton calculated in Atomic Mass Units (amu) or Daltons. Offered the first convincing argument for the existence of atoms, based on a well-established experimental results, Avogadro’s Number (6.02214076 x 10^23) which he published in a book in 1808 (Dalton’s Atomic Theory) Matters and Its Properties Dalton’s atomic theory by the scientific community paved - Is anything that occupies space and has mass the way of our current understanding of the atom - - Matter is everything around us. the modern model of the atom Classifications of Matter Elements are pure substances that consist of only one type of atom. Compounds are pure substances composed of two or more different elements chemically combined in fixed proportions. Mixtures are combinations of two or more substances or compounds physically blended together, but they retain their individual identities of properties Kinds of Mixtures Homogenous - These mixtures have uniform composition throughout and are often called solutions. Evenly distributed and examples are salt and water, 5. Texture milk, and juice - Refers to the surface quality of a material, whether it's Heterogenous - These mixtures have a non-uniform rough, smooth, soft, hard, etc. composition, meaning the different components are visibly distinct. Physically separated and reversible 6. Color and not evenly distributed. Ex. Salad, cereal, oil and - Its the visual perception of the way a material absorbs, water. reflects, or emits light. Properties of Matter 7. Luster Physical Property/Change - Describes how a material reflects light. It can be Chemical Property/Change categorized as metallic, non-metallic, and glassy. Physical Property/ Change 8. Melting Point 1. Mass - Is the temperature at which a solid turns into a liquid. Ex. - is the amount of matter in an object and it is typically Mercury can melt at - 38.83°C measured in units like kilograms or grams 9. Boiling Point 2. Volume - Is the temperature at which a liquid turns into a gas (or - is the amount of space occupied by an object or vapor) at a specific pressure substance. Mostly measured in centimeters or meters. 10. Conductivity 3. Density - Refers to the ability of a material to conduct heat or - is the mass of an object per unit volume. electricity. Ex. Metal is a good conductor of heat. density=mass/volume - Measurement of how tightly the object is pact together. Directly proportional- If the temperature increases, the pressure increases and vice versa 4. States of Matter - Is a way to describe the behavior of atoms and molecules 11. Solubility in a substance. (Solid, Liquid, Gas, and Plasma) - Is an ability of a substance to dissolve in another substance. Ex. Cup of tea, coffee, milk, and juice. 4.1 Solid - Matter that cannot flow (definite shape) and has a 12. Malleability and Ductility definite volume Malleability - Is the ability of a material to be deformed under 4.2 Liquid compression without breaking, often, seen in - Definite volume but takes the shape of its container. metals. The ability to be broken into thin (flows) sheets. Ex. Aluminum Ductility 4.3 Gas - Is the ability to be stretched into thin wires. Ex. Gold, - Substances without definite shape or volume can flow. copper, and silver. 4.4 Plasma 13. Hardness - Ionized gas that contains positive ions and electrons. Ex. - Is a measure of a material’s resistance to deformation or thunder and aurora borealis.\ scratching. Ex. Diamond is super hard. Physical properties are categorized into two: Intensive  - Properties that are independent of the amount of Residue- solid particle trapped by filter paper substance present in the material sample. Ex. Filtrate- Liquid that passed through filter paper Flammability, Density, and Boiling Point 2. Decantation Extensive - Separating a liquid from solid particles. - Properties that are dependent on the amount of 3. Evaporation substance on the amount of substance in a material - Separating a solute from a solvent sample. Ex. Mass, Surface area, and volume. - The mixture is heated to evaporate the solvent, leaving the solute behind Chemical Property/Change 4. Distillation 1. Reactivity - Separating liquids with different boiling points. - Refers to how readily a substance undergoes chemical 5. Column Chromatography reactions with the substances. Ex. Potassium - Separating mixtures of substances based on their differential distribution between a stationary Extremely Reactive and Extremely Unreactive phase and a mobile phase. Stronger affinity- move more slowly 2. Combustibility Weaker affinity- move fast - Is the ability of a substance to burn in the presence of oxygen. Ex. Wood and paper 6. Paper Chromatography - Separating mixtures of colored substances 3. Oxidation - Directly and proportional - Is a chemical reaction where substances gain oxygen or Stronger affinity- move fast lose electrons. Weaker affinity- move more slowly - Removal of oxygen reactant - It is either hydrogen is loss or gain and the same as the 7. Centrifugation oxygen - Separating components based on density, size, and viscosity 4. Corrosion Heavier component- moves outward and settles at the bottom. - Is the gradual deterioration of a material, often due to Lighter component- remain on top. chemical reactions with its surroundings. 8. Magnetism - Corrosion is a result of oxidation. - Separating magnetic materials (e.g. iron) from - Corrosion includes rust and rusting is a type of corrosion. non-magnetic materials - Used to attract and separate the magnetic 5. Acidity and Basicity particles - Are related to the substance's ability to donate or accept - Magnetism is caused by the motion of electric a proton (H+ions). Acids donate protons, while bases charges and is composed of atoms that have accept them. electric charges. - This can be determined through the PH scale 9. Solvent extraction - Separating substances that are solute in one solvent but not in another - You can selectively dissolve and separate specific components from a mixture Solute: the substance that was dissolved by the solvent. Solvent: a substance that dissolves the solute. 10. Crystallization - Separating a solute from a solvent by cooling and evaporating the solvent, causing the solute to crystallize and separate from the solution. Ex. Shampoo. Methods of separating mixtures 11. Sublimation - Separating mixtures where one component can 1. Filtration undergo sublimation (changing from a solid - Separating solid particles from a liquid or gas. directly into a gas) while one other remains a - The mixture is passed through a porous material solid. The sublimated component can be the (like filter paper or a sieve) that allows the liquid collection as a solid. or gas to pass through while trapping the solid particle.  ATOMS, MOLECULES, AND IONS - Formed when two or more atoms bond together chemically Atoms- is considered the basic building block of matter. - Process of chemical bonding ↳ is the process by which atoms are held Three tiny kinds of particles called subatomic particles: together to form compound molecules through sharing or transferring electrons. Protons- positively charged - To achieve stability Electrons- negatively charged ↳ Octet Rule Neutron- no charged or neutral - Needs 8 valence electrons to be stable Democritus- 400 BC - Believed that the smallest possible piece of Octet Rule matter was invisible. He named the smallest - Describes an atom’s preference for having 8 electrons in piece of matter “atomos” meaning “not to be cut” a valence shell. Aristotle - The rule only applies to s and p electrons - Declared all matter was made of only four elements: fire, air, water, and earth, also 3 Types of Octet Rule believed matter has just four properties: hot, cold, dry, and wet. Ionic Bonding John Dalton - Is the complete transfer of valence electron(s) between - Atomic theory atoms. - All matter is made of atoms - Ionic bonds are typically found in compounds between ↳ small to see, “uncuttable,” and indestructible. metals and nonmetals Joseph John Thompson: Plum pudding model - Hint that an atom is made of even smaller Ions- are electrically charged particles that are formed when particles atoms gain or lose electrons. - He was the first one who discovered electrons— discovered one presence of a negative particle Examples: in the atom. NaCl MgO NaBr MgS Ernest Rutherford: Planetary Model NaF CaSe - He discovered the nucleus NaI - Theorized that atoms have a small KCl LiI Neils Bohr: Borh’s Planetary models - He built the concept that has mass of an atom is Covalent Bonding contained mostly in the nucleus. - Is the sharing of electrons between atoms. This type of bonding occurs between two atoms of the same element or of elements close to each other in the ATOMIC NUMBER: “Z” periodic table. - Also known as the nuclear charge number of a chemical element is the charge. 2 Basic types of Covalent Bonding - The sum of protons and electrons Nonpolar Covalent Bond Protons- in a neutral atom this is the same as the number of - Is a bond in which the electrons are equally distributed electrons Polar Covalent Bond ATOMIC MASS: “A” - Is a bond in which the electrons are unequally distributed - Total number of neutrons and protons present in the nucleus of an atom of an element. Metallic Bonding - Exists in metals when a metal chemically bonds to either Z= protons=electrons a similar metal or other metals to form alloys A= neutrons+protons Neutrons= A-protons Examples: Copper (Cu) Gold (Au) Period- row Aluminum (A) Silver (Ag) Group- column Iron (Fe) Molecules Organic Compounds - organic compound, any of a large class of chemical compounds in which one or more atoms of carbon are covalently linked to atoms of other elements, most commonly hydrogen, oxygen, or nitrogen. Alkanes - Compounds that consist entirely of atoms of carbon and hydrogen bonded to another carbon to carbon and carbon to hydrogen. It is a single-bonded Alkenes - Have at least one carbon-carbon double bond Alkynes - Triple bond Ane- single Ene- double Yne- triple Naming Binary Molecular Compound Number of atoms Prefix Example 1 mono (NO) nitrogen monoxide 2 di (NO2) nitrogen dioxide 3 tri (N2O3) dinitrogen trioxide 4 tetra (N2O4) dinitrogen tetraoxide 5 penta (N2O4) dinitrogen pentaoxide 6 hexa (SF6) sulfur hexafluoride 7 hepta (IF7) iodine heptafluoride 8 octa 9 nona 10 deca