Unit 2. Matter and Energy PDF

1 Unit 2. Matter and Energy Topics: Classification, Physical and Chemical Properties of Matter t Dir  Topic Outcomes Goal 1. Classify matter and distinguish between physical and...

1 Unit 2. Matter and Energy Topics: Classification, Physical and Chemical Properties of Matter t Dir  Topic Outcomes Goal 1. Classify matter and distinguish between physical and chemical properties and changes. 2. Determine the quantitative analysis of chemical reactions.  What is matter? Matter is any material that occupies space and has mass It includes all solids, liquids and gases Liquid Gas Solid 5 Pure Substances A pure substance is made up of only one type of matter A pure substance cannot be separated easily Examples: Carbon dioxide, gold, pure water, salt Pure Substance Pure Substance Mixture Mixtures Mixtures are combinations of two or more pure substances that are not combined chemically t Dir  Mixtures carbon dioxide gas water flavouring sweetener flavouring Soft drink is a mixture of five different substances, but it looks and behaves like a single substance  Mixtures Mixtures can be separated in to their pure substances by techniques including decanting and filtration filtration decanting Examples: 1. Seawater (mixture of salt and water) 2. Air (mixture of carbon dioxide, nitrogen, oxygen) 3. Alloy (mixture of metals) Types of Mixtures You can see the properties of the different types of matter in a heterogeneous mixture as no dissolving occurs Heterogeneous mixtures are also called suspensions Examples: 1.Oil and water 2.Sand and water 3.Chocolate chip cookies Types of Mixtures In a homogenous mixture, you cannot see the difference between the types of matter. This is because dissolving occurs. Homogenous mixtures are also called solutions Examples: 1.Salt water 2.Clean air 3.Milk sifying matter as pure substances or mixtures We do: Classify the following as pure substances or mixtures Cordial Water Torch battery Gold Lead Lead Nitrogen Pencil Classifying matter as pure substances ANSWERS or mixtures Mixture Pure Substance Torch batter Lead Lead y Nitrogen Pencil Cordial Water Gold  Matter is anything that occupies space and has mass. A substance is a particular type of matter with uniform The classifications of matter include substances, Mixtures are a properties and mixtures, elements, and compounds. combination of a specific substances that composition. A retain their homogeneou It can be either an element individual properties s mixture or a compound. and can be (solution)has physically a uniform separated. An element A composition In a is a pure compound throughout. heterogen substance is a pure that consists eous substance of only one mixture, made up of type of atom. two or more the different components types of are not atoms evenly chemically distributed. combined in 14 fixed ratios. Three States of Matter 16 In the solid state, particles are closely packed and have a fixed position. They vibrate around their equilibrium positions but do not move past each other. Solids have a definite shape and volume. 17 In the liquid state, particles have more energy than in a solid. They are still close together but are able to move past each other. Liquids have a definite volume but take the shape of their container. 18 In the gas state, particles have even more energy than in liquids. They are widely spaced and move freely in all directions. Gases do not have a definite shape or volume and will expand to fill any container they are placed in. 19 Physical and Chemical Properties of Matter  Physical Properties of Matter Physical properties describe the characteristics of a substance that can be observed or measured without changingproperties Physical its chemical arecomposition. often used to identify and classify substances. 21  Intensive Physical Properties of Matter Color: The visual appearance of a substance to dissolve in a particular substance. solvent. Odor: The scent of a substance. Conductivity: The ability of a substance to conduct heat or Density: The mass of a substance electricity. per unit volume. Hardness: The resistance of a Melting Point: The temperature at substance to being scratched or which a solid substance changes into deformed. a liquid. Malleability: The ability of a Boiling Point: The temperature at substance to be hammered or rolled which a liquid substance changes into thin sheets. 22 into a gas. Extensive Physical Properties of Matter Depends on the amount of substance present. Mass: Refers to the amount of matter that makes up an object. Volume: The amount of space occupied by any three dimensional solid. Length: A measure of distance. 23  Chemical Properties of Matter Chemical properties describe how a substance interacts with other substances and how it undergoes changes in composition, leading to the formation of new substances. 24  Chemical Properties of Matter Flammability: The ability of a substance to ignite and burn in the presence of oxygen. Reactivity: How readily a substance Combustion: The chemical reaction undergoes chemical reactions with other between a substance and oxygen that results substances. in the release of heat and light. Acidity/Basicity: The level of acidity or Toxicity: The potential of a substance to basicity (alkalinity) of a substance, measured cause harm to living organisms. by its pH. Reaction with Water: How a substance Oxidation/Reduction: How a substance reacts with water to form new compounds. gains or loses electrons in reactions, leading to oxidation (loss of electrons) or reduction (gain of electrons). Corrosion: The tendency of a substance to 25 react with its environment, often leading to Changes of Matter  Chemical Reactions Chemical reactions are fundamental events in which substances (reactants) transform into new substances (products) with different chemical properties. To represent a chemical reaction chemical equation is used using chemical symbols and formulas to indicate the reactant and the products. Reactants Products These are the initial produce These are the new substances that substances formed as a participate in the result of the reaction. reaction and undergo a change. 27 A chemical equation is a Chemical Equation symbolic It consists of reactant formulas on the left side and product representation of a formulas on the right side, chemical reaction. separated by an arrow (→). coefficients Coefficients indicate the relative amounts of reactants and products. reactants products 28 Periodic Table Let us review! 29 PERIODIC TABLE: Element: Each box in the periodic table represents an element, which is a type of atom with a unique number of protons in its nucleus. Elements are identified by their atomic number, which also dictates their chemical properties. Atomic Number: The atomic number of an element is the number of protons in its nucleus. It determines an element's position in the periodic table and is used to arrange elements in increasing order. 30 PERIODIC TABLE: Periods: The horizontal rows in the periodic table are called periods. Elements within the same period have the same number of electron shells. Groups (or Families): The vertical columns in the periodic table are called groups or families. Elements within the same group share similar chemical properties and valence electron configurations. Main Groups: These are the columns labeled with numbers 1 to 18 on the left and right sides of the periodic table. The elements in the main groups are also referred to as representative elements. 31 PERIODIC TABLE: Transition Metals: These are located in the central portion of the periodic table, between the main groups. They include elements from groups 3 to 12. Inner Transition Metals: These are the two rows of elements separated from the main body of the periodic table. The lanthanides (rare earth elements) and actinides are examples of inner transition metals. Metals, Nonmetals, and Metalloids: Elements are classified into these three categories based on their physical and chemical properties. Metals are typically good conductors of heat and electricity, while nonmetals are poor conductors. Metalloids have properties that fall between metals and nonmetals. 32 PERIODIC TABLE: Valence Electrons: The electrons in the outermost energy level of an atom are called valence electrons. The arrangement of valence electrons often determines an element's chemical reactivity. Noble Gases: Group 18 elements are known as noble gases. They are chemically inert due to their stable electron configurations. 33 34 Elements and Compounds 35 36 37 Basic guide for naming different types of compounds: 1. Ionic Compounds These are compounds formed from a metal and a non- metal. Binary Ionic Compounds: Name the metal (cation) first, followed by the non-metal (anion) with its ending changed to "-ide." Example: NaCl – Sodium Chloride Example: MgO – Magnesium Oxide Ionic Compounds with Polyatomic Ions: Name the metal first, then name the polyatomic ion. Example: NaNO₃ – Sodium Nitrate Example: CaCO₃ – Calcium Carbonate 38 Common Compounds with their Chemical Formulas: 39 2. Covalent (Molecular) Compounds These are compounds formed from two non-metals. Binary Covalent Compounds: Use prefixes to denote the number of each atom and change the ending of the second element to "-ide." Prefixes: mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, deca- Example: CO₂ – Carbon Dioxide Example: N₂O₅ – Dinitrogen Pentoxide 40 Common Compounds with their Chemical Formulas: 41 3. Compounds with Polyatomic Ions These include a metal or a nonmetal and a polyatomic ion. A. Identify the Cation and Polyatomic Ion: The cation is usually a metal or ammonium ion, and the anion is a polyatomic ion. B. Balance the Charges: Use parentheses to indicate multiple polyatomic ions if necessary. Example: Calcium Nitrate Cation: Calcium (Ca²⁺) Anion: Nitrate (NO₃⁻) Charges: Ca²⁺ and NO₃⁻ Formula: Ca(NO₃)₂ (the subscript 2 outside the parentheses indicates two nitrate ions are needed to balance the charge) 42 4. Acids The naming depends on whether the acid is binary or contains a polyatomic ion. Binary Acids: Use the prefix "hydro-" followed by the name of the non-metal with the suffix "-ic" and "acid." Example: HCl – Hydrochloric Acid Example: H₂S – Hydrosulfuric Acid Oxyacids: Name based on the polyatomic ion: If the ion ends in "-ate," change it to "-ic" and add "acid." Example: H₂SO₄ – Sulfuric Acid (from sulfate, SO₄²⁻) If the ion ends in "-ite," change it to "-ous" and add "acid." Example: H₂SO₃ – Sulfurous Acid (from sulfite, SO₃²⁻) 43 Acids are compounds that release hydrogen ions (H⁺) when dissolved in water. Note: The naming depends on whether the acid is binary or contains a polyatomic ion. Identify the Acid Type: Hydrohalic acids and oxyacids. Write the Formula: Use the anion part and adjust the number of hydrogen ions to balance the charges. Example: Sulfuric Acid Anion: Sulfate (SO₄²⁻) Hydrogen: Two hydrogen ions needed to balance the charge Formula: H₂SO₄ 44 Acids can be broadly classified into two main types: hydrohalic acids and oxyacids. A. Hydrohalic Acids Hydrohalic acids are binary acids, meaning they consist of hydrogen and one other element, typically a halogen (Group 17 elements on the periodic table). Composition: Hydrogen (H) + a halogen (F, Cl, Br, I) Naming Convention: The acid name begins with "hydro-." The root name of the halogen follows. The name ends with “-ic acid.” Examples: Hydrochloric Acid (HCl): Composition: Hydrogen + Chlorine Formula: HCl Hydrobromic Acid (HBr): Composition: Hydrogen + Bromine Formula: HBr Hydroiodic Acid (HI): Composition: Hydrogen + Iodine Formula: HI Hydrofluoric Acid (HF): Composition: Hydrogen + Fluorine Formula: HF 45 B. Oxyacids Oxyacids (or oxoacids) contain hydrogen, oxygen, and another element (typically a nonmetal). The is that the hydrogen is bonded to an oxygen atom. Composition: Hydrogen (H) + Oxygen (O) + a central nonmetal atom Naming Convention: The name is based on the polyatomic ion (without "hydro-"). If the polyatomic ion ends in “-ate,” the acid name ends with “-ic acid.” If the polyatomic ion ends in “-ite,” the acid name ends with “-ous acid.” Examples: Sulfuric Acid (H₂SO₄): Composition: Hydrogen + Sulfate ion (SO₄²⁻) Formula: H₂SO₄ Nitric Acid (HNO₃): Composition: Hydrogen + Nitrate ion (NO₃⁻) Formula: HNO₃ Phosphoric Acid (H₃PO₄): Composition: Hydrogen + Phosphate ion (PO₄³⁻) Formula: H₃PO₄ Carbonic Acid (H₂CO₃): Composition: Hydrogen + Carbonate ion (CO₃²⁻) Formula: H₂CO₃ Sulfurous Acid (H₂SO₃): Composition: Hydrogen + Sulfite ion (SO₃²⁻) Formula: H₂SO₃ 46 Common Compounds with their Chemical Formulas: 47 5. Organic Compounds These follow systematic nomenclature based on the structure. Alkanes: Named based on the number of carbon atoms with the suffix "-ane." Example: CH₄ – Methane Example: C₆H₁₂ – Hexane Alcohols: Replace the "-e" in the alkane name with "-ol." Example: CH₃OH – Methanol Example: C₂H₅OH – Ethanol 48 In organic chemistry, the prefixes for naming hydrocarbons (like alkanes) indicate the number of carbon atoms in the molecule. 49 Common Compounds with their Chemical Formulas: 50  Types of Reactions 1. Combination (Synthesis) Reactions Two or more substances combine to form a single, more complex substance. General Form: A + B → AB Example: Formation of Water (Hydrogen and Oxygen) 2H₂ + O₂ → 2H₂O molecules of hydrogen gas (H₂) + 1 molecule of oxygen gas (O₂) to form 2 molecules of water (H₂O) 51 Combination (Synthesis) Reactions 52 Combination (Synthesis) Reactions 2 53  Types of Reactions 2. Decomposition Reactions A single substance breaks down into two or more simpler substances. General Form: AB → A + B Example: Thermal Decomposition CaCO₃ → CaO + Calcium carbonate (CaCO₃)CO₂ decomposes into calcium oxide (CaO) and carbon dioxide (CO₂) upon heating. 54 Decomposition Reactions 55  Types of Reactions 3. Single Displacement Reaction (Substitution) One element displaces another element in a compound, leading to the formation of a new compound and a free element. General Form: Example: Displacement of hydrogen by zin A + BC → AC + B Zn + 2HCl → ZnCl₂ Where: + H₂ A is the more reactive element. BC is the compound in which A displaces element B. AC is the new compound formed. B is the displaced element, which becomes a free element. 56  In single displacement reactions, a more reactive element is the one that is able to "take the place" of another element in a compound because it has a stronger tendency to form chemical bonds. Elements that are higher in the reactivity series are typically more likely to displace elements that are lower in the series. In a reaction between zinc and hydrochloric ac Zn + 2HCl → ZnCl₂ + H₂ 57 Single Displacement Reaction (Substitution) 58  Types of Reactions 4. Double Displacement Reaction (Metathesis) Ions from two different compounds exchange places, resulting in the formation of two new compounds. General Form: AB + CD → AD + CB AB + C D→ A D + C B Example: AgNO₃ + NaCl → AgCl + NaNO₃ silver nitrate + sodium chloride → silver chloride and sodium nitrate (Formation of silver chloride and sodium nitrate) 59 Double Displacement Reaction (Metathesis) +H2O 60  Types of Reactions 5. Neutralization Reaction Reaction occurs between an acid and a base, resulting in the formation of water and a salt. General Form: acid + base → salt + water 61  Components and process of a neutralization reaction: 1. Acid: An acid is a substance that donates protons (H⁺ ions) or accepts electron pairs. Acids have a sour taste and can cause a tingling or burning sensation. 2. Base: A base is a substance that accepts protons (H⁺ ions) or donates electron pairs. Bases are often called alkaline substances and have a bitter taste and slippery feel. 3. Salt: In chemistry, a salt is a compound formed from the reaction between an acid and a base. It consists of a positively charged ion (cation) from the base and a negatively charged ion (anion) from the acid. 4. Water: Water (H₂O) is always produced as a product of neutralization reactions. One molecule of water is typically formed for each proton donated by the acid and accepted by the base. 62  Types of Reactions 5. Neutralization Reaction Reaction occurs between an acid and a base, resulting in the formation of water and a salt. General Form: acid + base → salt + water acid base salt water Example: HCl + NaOH → NaCl + H₂O Hydrochloric acid + Sodium hydroxide → Sodium chloride + Water 63 64 Neutralization Reaction 65 Potential of Hydrogen (pH) The concentration of hydrogen ions in a solution, a measure of the solution's acidity or basicity. 66  Types of Reactions 5. Combustion Reaction A combustion reaction (burning) involves the rapid combination of a fuel with oxygen gas to produce heat, light, and new chemical products, primarily carbon dioxide and water. General Form: Fuel + Oxygen → Carbon Dioxide + Water + Energy Carbon dioxide methane oxygen water Example: CH₄ + 2O₂ → CO₂ + 2H₂O + Energy 67  Combustion Reaction of elements and compounds with oxygen 68  Balancing Chemical Equations Chemical equations must be balanced to satisfy the law of conservation of mass. 69  Balancing Chemical Equations  The same number and type of an atom must be present on each side of the equation.  Never change the subscripts in the equation. Balancing is done by adding coefficients. 70  Balancing Chemical Equations H₂ + O₂ H₂ 2H₂ O₂ 2H₂ H=2 H=O H =4 HO=4 O=2 O2 = 1 O =2 O =2 (Unbalanced equation) (Balanced equation) 71 Balancing Chemical Equations https://www.youtube.com/watch?v=zmdxMlb88Fs 72 Task 73  Stoichiometric Calculations Stoichiometry is a term used to describe quantitative relationships in chemistry. It is the quantitative study of reactants and products in a chemical reaction. Whether the units given for reactants (or products) are moles, grams, liters (for gases), or some other units, moles is used to calculate the amount of product formed in a reaction. This approach is called the mole method, which means simply that the stoichiometric coefficients in a chemical equation can be interpreted as the number of moles of each substance. 74  The relationships between amounts (in moles) and masses (in grams) of reactants and products can be used to solve stoichiometry problems. 75 Note: The key to solving stoichiometry problems is mole ratio, regardless of the physical state of the reactants For most chemical reactions there are basically three types of conversions: 1. mol A mol B (1 step) *Identify the molar ratio 2. mol A gB (2 steps) 3. gA gB (3 steps) 76 77 Solving a Stoichiometry Problem https://www.youtube.com/watch?v=7Cfq0ilw7ps 78  Balancing Chemical Equations H₂ + O₂ H₂ 2H₂ O₂ 2H₂ H=2 H=O H =4 HO=4 O=2 O2 = 1 O =2 O =2 (Unbalanced equation) (Balanced equation) 79  Molar Mass The molar mass of a substance is the mass in grams of one mole of the substance. Molar masses are calculated by summing the atomic masses of all the elements appearing in a chemical formula. 1 𝑚𝑜𝑙 𝐻 2 𝑂 Example: 18.01582 𝑔 𝐻 2 𝑂 80 Stoichiometry Mole-Mole/Mole Ratio A mole ratio is a conversion factor that relates the amounts in moles of any two substances involved in a chemical reaction. 2H₂ + O₂ → 2H₂O 2𝑚𝑜𝑙 𝐻 2 2 𝑚𝑜𝑙 𝐻 2 2𝑚𝑜𝑙𝑂2 2𝑚𝑜𝑙 𝐻 2 𝑂 81  Example Stoichiometry Problem Example No 1 In the reaction between hydrogen gas (H₂) and oxygen gas (O₂) to form water (H₂O), how many grams of water are produced when 4 moles of hydrogen gas react with excess oxygen gas? Equation: Calculate Desired Quantity: (unbalanced) H₂ + O₂ → H₂O 2𝑚𝑜𝑙 𝐻 2 𝑂 4 𝑚𝑜𝑙 𝐻 x 2 = O 2 𝑚𝑜𝑙 𝐻 2 (balanced) 2H₂ + O₂ → 2H₂O 4 moles of (H₂) Given: Molar Mass of18.01528 water: 𝑔 𝑚𝑜𝑙 Mole Ratio: 2 𝑚𝑜𝑙 𝐻 2 18.01528 𝑔 O x = 72.06112 g 2𝑚𝑜𝑙 𝐻 2 𝑂 𝑚𝑜𝑙 82 12.5 g 1 mol Al 1 mol Al (SO 4)3 342 g Al(SO4) X X 2 X 2 Al 3 27 g Al 2 mol 1 mol Al(SO 2 4) Al 3 83 Example No. 3 84  -End- Thanks! 85