Presentation on theme: "Physical Science I Chemistry"— Presentation transcript:
1Physical Science I Chemistry Unit IIPhysical Science IChemistry
2Chemistry Terms Matter - anything that has mass and takes up space Chemistry - is the study of matter, its properties and the changes or chemical reactions that matter can undergo.Ex. rusting, combustion of fuel/candle wax, explosion of TNT, vinegar and baking soda
3Pure Chemistry - describing known substances and discovering new compounds for research purposes. Applied Chemistry – the search for uses for chemical substances. Modern society demands chemistry understanding.Ex. technology; government.
4Mass- The amount of matter an object contains in grams (g). States of Matter– 3 physical states:Solid definite volume/shapeLiquid definite volume/indefinite shapeGas indefinite volume/shape(aq)=aqueous; dissolved in H2O
5Physical Property- a characteristic of a substance; can be observed without changing into a new substance.Ex. State of matter, hardness, melting point, boiling point, odour, solubility colour, malleability, ductility, brittleness, conductivity.
6Physical Change- a change in state of a substance (no new substance formed). Ex. melting (s to l); evaporation/boiling (l to g); condensation (g to l); sublimation (s to g)H2O (s) H2O (l)heat
7Chemical Property- a characteristic behaviour of a substance that occurs when a substance changes into a new substance.Ex.2 Mg(s) +O2(g) MgO(s) Mg ribbon+ lightenergy
8Chemical Change- a change in which one or more NEW substances are formed. Ex.coal combustionC(s) + O2(g) CO2(g) + heatrusting4 Fe(s) O2(g) Fe2O3(g)
9Indicators of Chemical Change – new colourheat/light given offBubbles of gasPrecipitate (solid) formationChange is difficult to reverse
10Mixture – contains 2 or more pure substances. Two Types:Homogeneous Mixture- aka “solution”- have only one visible phase throughout.ex. air, apple juice, salt waterHeterogeneous Mixture- contain 2 or more visible components or phasesex. soil, soup
11Pure Substance – made up of only one type of atom or atom combination. (Ex. O2, H2O)Stays the same in response to physical change.Two Types: Compounds and Elements
12Can be broken down to elements via chemical means. Compounds - pure substances that contain two or more different elements in a fixed proportionie., CO2, H2O, C6H12O6 and NaClCan be broken down to elements via chemical means.Ex. 2 NaCl (l) Na (l) + Cl2 (g)electricity
13Element Names are always written in lowercase letters. Elements - pure substances that CANNOT be broken down into simpler substances by regular laboratory conditions; made up of 1 type of atom.ie., oxygen, nitrogen, carbon and phosphorusElement Symbols are always written with the first letter uppercase and the second letter lowercase.Ex. Au, Mg, ArElement Names are always written in lowercase letters.
14How can we remember these? Diatomic Molecules – There are 7 elements that are diatomic gases in their natural state.These are: H2 O2 F2 Br2 I2 N2 Cl2Also P4 and S8How can we remember these?HOFBrINCl PS! (or an upside down “L” on the periodic table).
16Reactants – starting materials. Products – new substances formed. Chemical ReactionReactants Products“go to form”
17Periodic Table Mid 1800s- 65 known elements. Began to recognize patterns after recording reactivity, masses, etc.
18Dmitri Mendeleev ( )Wrote out elements in order of increasing atomic mass, result was a table.“periodic” table- “periodic” meaning repeating patterns and properties.We now organize the periodic table according to atomic numberAlso organized according to # of electrons (e-) in atoms of each element.
19Periodic Table- A Review It is designed to arrange elements in a pattern that helps us predict properties and bonding patterns of elements.Elements are organized by Atomic Number and Number of Electrons.The periodic Table is arranged in rows and columns.
20Period: horizontal row (7 in total) : atomic mass and atomic number increase( )from L to R.Group/Family: vertical columns (18): Elements of the same group have similar but not identical properties.Some groups have species names:Group 1- Alkali Metals Group 17- HalogensGroup 2- Alkaline Earths Group 18- Noble GasesLanthanides (rare earth)Actinides
21Groups have 2 numbering systems: New Group 1-18Old Roman Numerals/LettersIA-VIIIA - Representative ElementsIB-VIIIB - Transition Elements.
22METALS Metals and Nonmetals Nonmetals Metalloids H He Li Be B C N O F 1He21Li3Be4B5C6NonmetalsN7O8F9Ne102Na11Mg12Al13Si14P15S16Cl17Ar183K19Ca20Sc21Ti22V23Cr24Mn25Fe26Co27Ni28Cu29Zn30Ga31Ge32As33Se34Br35Kr364METALSRb37Sr38Y39Zr40Nb41Mo42Tc43Ru44Rh45Pd46Ag47Cd48In49Sn50Sb51Te52I53Xe545MetalloidsCs55Ba56Hf72Ta73W74Re75Os76Ir77Pt78Au79Hg80Tl81Pb82Bi83Po84At85Rn866*Fr87Ra88Rf104Db105Sg106Bh107Hs108Mt1097WLa57Ce58Pr59Nd60Pm61Sm62Eu63Gd64Tb65Dy66Ho67Er68Tm69Yb70Lu71Ac89Th90Pa91U92Np93Pu94Am95Cm96Bk97Cf98Es99Fm100Md101No102Lr103
23Types of Elements The Metals The staircase line divides the elements into two major categories: the metals and the nonmetalsThe ratio of metals to nonmetals is about 4:1The MetalsMetals are shiny, electrically conductive elements.They are also malleable (can be hammered into shapes) and ductile (can be stretched into wire).With the exception of mercury, they are all solids at room temperature (25°C).
24The NonmetalsNonmetals are dull and are very poor conductors or nonconductors of electricity.The solid nonmetals are brittle.As a group, the nonmetals exhibit the three states of matter at room temperature.eg, carbon is a solid, nitrogen is a gas, and bromine is a liquid.
25The location of hydrogen in the periodic table is unusual. Hydrogen is a nonmetal, but in some periodic tables it is located in the top left hand corner of the periodic table (i.e. on the metals side).Due to the fact that hydrogen has some metallic properties in addition to nonmetallic properties.2 groups: Alkali Metals and Halogens (1 and 17).
26The MetalloidsThe metalloids are elements that possess both metallic and nonmetallic properties.For example, silicon is shiny and conducts electricity (like a metal) , but it is brittle (like a nonmetal).Metalloids are also known as the semimetals.
27Representative Elements The representative elements illustrate the entire range of the properties of the elements.[Group 1, 2, 13-18].Sometimes known as the group A elements, they are organized into chemical families based on their specific chemical and physical properties.
28The Transition Elements The transition elements are all metals.They are different from the representative elements because of their electron arrangements which in turn gives them properties that are a little different from the metallic representative elements.Inner Transition Elements:(Lanthanides, Actinides) Same as transition, but removed from main table as a matter of convenience in organizing table.
29Elements in the periodic table are organized based on shared properties. Metalloids (staircase)
30Molecular Substances Exist as groups of atoms called molecules Molecules are substances composed of nonmetallic elementsNitrogen – N2Methane – CH4
31You must memorize these Mono-atomic molecular elementsNoble Gases (group VIIIA or 18)HeHeliumNeNeonArArgonKrKryptonXeXenonRnRadonYou must memorize these
37Molecular Compounds Consist of two or more nonmetallic elements 2 types of molecular compoundsBinary molecular compoundsTernary molecular compounds
38Binary vs ternary Molecular Compounds Type of CompoundMolecular formulanameBinaryH2OwaterH2O2hydrogen peroxideNH3ammoniaCH4methaneTernaryCH3OHmethanolC2H5OHethanolC12H22O11sucroseMemorize the names and formulas of common molecular substances as per the chemistry facts sheet
39Binary Molecular Compounds Composed of 2 nonmetalsCO2 , CCl4 , BF3 are examplesMany are identified by common namesie., water = H2O ammonia = NH3System for naming and writing formulas established by I.U.P.A.C.International Union for Pure and Applied Chemistry
40Requires a system of prefixes: prefix 1 mono 2 di 3 Tri 4 Tetra 5 Numberprefix1mono2di3Tri4Tetra5Penta6hexa7Hepta8Octa9nona10decaThis table is on your chemistry facts page
41RULES FOR NAMING BINARY MOLECULAR COMPOUNDS Write the name of the first element of the formula in full.Shorten the name of the second element and add the “ide” ending.Use prefixes to indicate the number of atoms of each element in the molecular formula.The prefix mono on the first name is optional.
42monocarbon tetrachloride. SampleWrite the IUPAC name for CCl4The first element is C.Its full name is carbon.The second element is chlorine.Its name is shortened to “chlor”, and the suffix “ide” is added to give chloride.The prefix mono (1) is added to carbon, and the prefix tetra (4) is added to chloride to give the name:monocarbon tetrachloride.The prefix mono can be omitted from the first element name to give:carbon tetrachloride.
45Chemical BondingMolecular compounds like B2H6 are held together by bonds.A chemical bond is the force of attraction between atoms.In molecular compounds the bond is the force of attraction occurs between nonmetallic elementsThis type of bond is called a covalent bond
46Atomic TheoryAtom – the smallest particle of an element that retains the properties of that element.Atoms are thought to be composed of negatively charged particles called electrons and a dense central region called the nucleus
47Within the nucleus are found positively charged particles called protons and neutral particles known as neutronsElectrons are believed to exist a specific distances from the nucleus called energy levels
48Electron Energy Level Diagrams Representative Elements Show electron arrangements within an atom’s energy levels.We can predict them using the following:Atomic numberPeriod numberGroup numberElectrons per energy level
49Electron Energy Level Diagrams Representative Elements Atomic numberAtomic # represents the number of protons in the nucleus of an atom.the # protons = # electrons. Example: Carbon has atomic # 6 which means C has 6 protons and 6 electrons)nucleus6+6 electrons
50Electron Energy Level Diagrams Representative Elements Period Numbertells us how many energy levels contain electronsEg Carbon is in the second row of the periodic table thus it is in period 2 and has electrons in 2 energy levels.2nd1st6+
51Electron Energy Level Diagrams Group # (family number)The group # tells us about electrons in the outer energy level of an atom (valence electrons)
52Electron Energy Level Diagrams Representative Elements We will deal with the representative elements only(for groups 13 and above valence electrons = the last digit):13, 14, 15, 16, 17, 18C has 4 valence electrons since it is group 144e-2nd1st6+
53Electron Energy Level Diagrams Representative Elements Period#of elements in the periodEnergy levelmax # of e-1283418
54Electron Energy Level Diagrams Representative Elements 2nd2e-1st6+
55Electron Energy Level Diagrams Representative Elements Example: Draw an electron energy level diagram for an atom of aluminumGroup 133e-Fill in the nonvalence electrons with the maximums per energy levelPeriod 38e-2e-Atomic number1313+
56Energy level diagrams - ions Recall the noble gases are unreactiveAll noble gases have filled valence energy levels
57atoms react by changing the number of electrons to try and get the same structure of the nearest noble gasIn other words, atoms either gain or lose electrons to become stableMetals lose electrons to have the same electron arrangement as the nearest noble gasNonmetals gain electrons to have an electron arrangement of the nearest noble gas.
60Ions Metals lose electrons to form positive ions called cations Nonmetals gain electrons to form negative ions called anionsBoth ions have noble gas stability
61Ionic compounds Composed of oppositely charged ions Held together by ionic bonds3 categories of ionic compounds :1) Binary ionic compoundssimple ions (only single charges)multivalent ions (more than one charge)2) Polyatomic ions (complex ions)3) Hydrates
62Binary ionic compounds Binary ionic compounds are composed of a metal ion (+) and non-metal ion (-).Naming binary ionic compounds:Name the cation (+) by writing the full name of the metal.Name the anion (-) by shortening the name of the element and add the -ide ending.
63Binary ionic compounds NaCl sodium and chlorine sodium chlorideCaF2 calcium and fluorine calcium fluorideK2O potassium and oxygen potassium oxideIMPORTANT: Do Not use prefixes - they are for molecular compounds (two non-metals)
64Rules for Writing Binary Ionic Formulas: Write down the symbols of the ions involved.Determine the lowest whole number ratio of ions that will give a net charge of zero.Write the formula removing all charges.
65Write a chemical formula for a compound that contains Calcium ions and Bromide ions. SampleWrite down the symbols of the ions involvedCalcium is group IIA, Ca2+Bromide is group VIIA, Br –Determine the lowest whole number ratio of ions that will give a net charge of zero. Use the crossover methodCa Br –Ca Br2
66Binary Ionic Compounds The Stock System Ions of a certain elements can have more than one possible charge.Such elements are called multivalent species.Example 1: tin forms two common ions:Sn2+ and Sn4+The Stock System is used to name ions like theseSn2+ is called tin (II) and Sn4+ is called tin (IV)
67Stock System Example too! Cu+ is copper (I) Cu2+ is copper (II) The periodic table lists the ions that have stock names.
69Stock SystemEgg Sample: Write the chemical formula for iron(II) chloride.Write the symbols of the ions involvedIron (II) (the roman numeral tells us it has a 2+ charge) Fe 2+Chloride (has a 1- charge) Cl –Determine the lowest whole number ratio of ions that will give a net charge of zero.Use the criss cross method:Fe Cl –FeCl2
70Write formulas for:Titanium (IV) fluorideTitanium (II) fluorideNickel (II) oxideLead (IV) sulfide
71Naming Ionic Compounds - Polyatomic ions polyatomic ion (complex ion) - is a group of atoms that are covalently bonded which then gain or lose electrons to become stableExample:The ammonium ion, NH4+, consists of one nitrogen atom and four hydrogen atoms which as a group have lost one electron.
73Writing Chemical Formulas for Compounds with Polyatomic Ions: write the cation symbol first and the anion symbol last. balance the charges by providing the appropriate numerical subscript for each ion.
74Write the a chemical formula for each compound: magnesium chlorate Mg2+ ClO3-put brackets around the complex ionMg2+ (ClO3) –criss cross the chargesMg (ClO3)2iron(III) sulfateFe2(SO4)3)
75Naming Ionic Compounds Ionic Hydrates An ionic hydrate is a compound that decomposes upon heating to release waterWater is part of its crystalline structure.sampleCuSO4●5H2O is copper(II)sulfate pentahydrate
76Each ionic hydrate has two parts to its name: A number of molecules of waterIonic saltCoCl2●2 H2OA separatorcobalt (II) chloridedihydrate
77U do zinc sulfate heptahydrate potassium sulfate decahydrate nickel (II) nitrate tetrahydrate
78Acids – hydrogen compounds All are hydrogen compounds dissolved in waterAcids can be simply defined as substances that release hydrogen ions (H+) in waterSubstances dissolved in water are denoted by a subscript (aq) written after their formulaEg. HCl(aq)Acids turn blue litmus red
79Rules for Naming Acids: name the hydrogen compound as if it were an ionic compound.(all of these compounds should end in - ide, -ate, or -ite.)depending on the ending convert the ionic name to the acid name.Ionic name acid namehydrogen _______ide → hydro _____ic acidhydrogen _______ate → _________ ic acidhydrogen _______ite → ________ous acid
80Rule #1: hydrogen…ideIf the aqueous hydrogen compound begins with “hydrogen” and ends in “ide”, then:Replace hydrogen with hydro and ..replace the “ide” ending of the anion with ic acidExample: HCl (aq) Hydrogen chloride → hydrochloric acid
81Rule #2: hydrogen…..ate :If the aqueous hydrogen compound begins in “hydrogen” and ends in “ate” then:drop the name hydrogen (do not replace it)replace the “ate” ending of the anion with -ic acidExample: HClO 3 (aq) hydrogen chlorate → chloric acid
82Rule #3: hydrogen…iteIf the aqueous hydrogen compound begins in “hydrogen” and ends in “ite” then:drop the name “hydrogen” (do not replace it)replace the “ite” ending with -ous acidExample: HNO2 (aq) hydrogen nitrite → nitrous acid
83Bases Sample Bases are substances that behave in opposition to acids. ionic compounds that contain the hydroxide ion (OH-).Sodium hydroxide – NaOH (aq)Sample
84Properties of Bases: turn red litmus blue neutralize acids have high pH (> 7)form slippery solutionstend to have a bitter tastepH scale
85Chemical Changecommunicated in sentence form or as chemical equations.
86Chemical equations have four parts: 1 chemical formulas2 subscripts for states of matter(s) solid(l) liquid(g) gas(aq) aqueous - dissolved in water3 numerical coefficientsindicates how many atoms/molecules are involved4 reaction symbolsthe "+" sign on the reactants (left) side is read as "reacts with"the arrow ( → ) is read as "to produce"the "+" sign on the products (right) side is read as "along with".
87Chemical EquationsTwo molecules of diesel fuel react with 49 molecules of oxygen to produce 32 molecules of carbon dioxide and 34 molecules of water.
88Evidence for Chemical Change: Chemical changes involve changes in make up - new substances are formed with new propertiesPhysical changes involve changes in state without a change in make up.
89Evidence of Chemical Change 4 indicators of chemical reaction:energy changecolour changeprecipitate formationgas formation
90a rock warmed by the sun all day loses its heat at night milk goes sour when left out of the fridgebubbles form in a glass of cold water as it warmsbubbles and steam rise out of a kettle of boiling waterpaint dries on a hot day.
91The Law of Conservation of Mass In a chemical reaction the mass of the reactants before a chemical reaction equals the mass of the products after the reaction is complete.Antoine Lavoisierplaced mercury(II) oxide powder (a red powder) in a test tube, sealed it, and then weighed it carefully
92heated it and observed that the red powder gradually changed into a grey liquid reweighed the sealed tube after the reaction was complete and observed that its mass had not changedopened the tube and noticed a rapid release of a gas which was later learned to be oxygen. The grey liquid was mercury metal.
93Balancing Chemical Equations All representations of a chemical change must reflect the law of conservation of massChemical equations must obey the law of conservation of massThe number of atoms of each element must be the same on both sides of the equationFor this reason all chemical equations we write must be balanced.
94Balancing Chemical Equations sampleMercury(II)oxide forms mercury and oxygenReactants ProductsHgO(s) → Hg(l) O2(g)1 Hg Hg1O O equation is unbalanced2HgO(s) → 2 Hg(l) O2(g)2 Hg Hg2O O equation is balanced