Chemistry

ChemistrySections 5.1, 5.2, 5.5, 5.6, 5.7, 5.8, 5.9, 5.11, 5.12, 5.13, 6.5, 6.6, 6.7, 6.19, 7.1, 7.2, 7.3, 7.5,

1An introduction to chemistryChemistry can be defined as the study of chemicals and their reactions.Chemicals may be described by their physical characteristics or their chemical characteristics;Physical characteristics include things like colour, state at room temp., smell, boiling or melting points.Chemical characteristics mean how a chemical reacts with other chemicals. A chemical change occurs when a substance changes to a new substance.2MixturesMost chemicals exist in nature as mixtures, made up of 2 or more substances.These mixtures may be either homogeneous or heterogeneous.Homogeneous mixtures are those in which the components are not distinguishable, is completely uniform. Ex coffee or chocolate ice creamHeterogeneous mixtures are those in which the components are distinguishable. Ex rocky road ice cream, stew3Homogeneous mixtures-

Heterogeneous mixtures-

4Pure SubstancesAre not as common as mixtures, consist of elements or compoundsElements are the simplest form of matter that can exist under natural conditions. Ex. Hydrogen, carbon, sodiumCompounds are pure substances that contain two or more different elements in fixed proportions. Compounds are usually identified with a chemical formula, a combination of letters and numbers to tell you what type and how many of each element is present. Ex. H2O5H2O

6WHMISStands for Workplace Hazardous Materials Information System Is a system to inform those using or exposed to chemicals the hazards they may encounter.Every chemical used in the school (cleaners included!) comes with a MSDS (Material Safety Data Sheet) that describes hazards associated with the chemical, disposal procedures etc.Complete questions 1, 4, 10 12 on page 1757Elements and the Periodic TableSection 5.5 8The periodic tableOrganizes elements according to their atomic structure, physical and chemical properties. The columns (up and down) are known as groups and the rows (across) are known as periodsChemical families are groups of elements that have similar propertiesWe can use the organization of the elements in the periodic table to predict their reactivity (how well an element will react)9The Periodic TableInteractive Periodic Table

Periodic Table: Groups and Trends10ElementsAn element is a substance made up of only 1 type of atom. There are about 112 different elements that make up the periodic table of the elements.On the periodic table each atom type has its information. For example

Atomic no.SymbolNameMass no.11Element definition copy it downCompound definitionMolecule definitionExercise to cut out and line up each in table form?Periodic TableAny atom can be identified by the atomic no., the symbol or by the name. For instance...

Atomic no.SymbolNameName SymbolAtomic No.HydrogenFe12IronMagnesiumHMg126The information from the table can also be shown as:115B12Describe metals, non metals, elements in order of atomic numberPlay element bingo New dir pg 45 Q1

Questions pg 184- 186Using table 1 on page 185, compare metals to non metals.Where can metals and nonmetals be found on the periodic table.Describe the four chemical families of the periodic table.Fill in the following table about sub atomic particles

ParticleLocationChargeSymbolProtonElectronNeutron

13What it meansThe Atomic Number:= number of protons = number of electrons (as an atom has the same of each)

The Mass Number:= number of protons + neutrons - why are electrons not included in the mass no?So for BoronProtons = Electrons = Neutrons = 555.811What about Phosphorus?Protons =Electrons = Neutrons = 151516115B14Copy slide including examplePractise working out number of protons, electrons and neutrons Zn, Fe, C, AlElectron configurationElectrons travel in orbits or orbitals around the nucleus. The atomic number on the periodic table tells you how many electrons each element has.Because atoms are electrically neutral, the number of electrons equals the number of protons. 15ELECTRON ARRANGEMENTElectrons are very fast moving. They are arranged in shells around the nucleus. The first shell fits

The second fits

The third fits

So the electron shell for 12Mg would be2 e8 e8 eInteractive periodic table2, 8, 216Write on board Li (2,1) Ca (2,8,8,2) P (2,8,5) they need to write the electron arrangement Then 2,8,7 (Cl), 2,6 (O) 2,8,1(Na)

Ionic BondingNa+ Cl

2,8,1

2,8,7What does the atomic model look like for each?What is the numerical electron configuration for each? 281 and 287How many electrons in 3rd energy level (outer shell) of Na?How many electrons in 3rd energy level of Cl?What is the easiest way for each to get a full outer shell?Na donates electron to Cl to form ionsIn Na ion positive or negative? And Cl Opposites attract. new compound NaCl pg 164 crystal latticeWhat about MgCl2, ZnO, MgO, KIDS cut out ion flashcards H/O and find partners to bond withIONIC FORMULAESo Mg2+ will be attracted to Cl-.Because Mg is 2+ and Cl is only 1-, Mg will attract 2 Cls.The compound formed will be MgCl2.The subscript shows that there are 2 Cls for each Mg.If the starting ions were Cu2+ and S2-, the 2 ions have the same charge. So each Cu will only attract 1 S. The compound formed will be CuS.There are never any charges on the final product - they balance out18If mg is 2+ how many cl- ions will it attract?Create ionic compounds for Na+Cl-(NaCl), Li+ S2-(Li2S) Al3+I-(AlI3) what about Fe3+o2- (Fe2(o)3 Why swap and drop try Al3+ so42- Al2(So4)3 and mg2+ po43- (Mg3(po4)2The mass number tells you the mass of the element and when rounded to the nearest whole number can be used to determine the number of neutrons inside the nucleus.Mass number atomic number = # of neutrons.Ex. Oxygen Atomic # = 8Mass # = 16

8 p +8 n 2 e6 e19IonsElements are most stable where their outer electron shell or orbit is full.Elements whose orbit are almost full lose or gain electrons, and become ions to achieve stabilityElements that gain electrons (and therefore a negative charge) form anions.Elements that lose electrons (and therefore have a positive charge) form cations.20AnionsAre formed when non-metals gain electrons.What was once a neutral atom becomes a negatively charged ion.The value of the charge is equal to the number of electrons gained.21CationsAre formed when metals lose electrons What was once a neutral atom becomes a positively charged ion.The value of the charge is equal to the number of electrons lost

22Naming IonsCations are named by simply stating the element from which it forms followed by the word ionEx. Sodium ionAnions are named by stating the elements from which it forms and replacing the ending with ideEx. Chloride

23Compounds: Ionic Bonding How do atoms become stable ions?Ionic bonding animation24Types of IonsAnionsNumber of electrons is greater than the number of protons

Negative chargeCationsnumber of electrons is less than the number of protons.

Positive charge25Determining iongeneral guidelinesMetals form cations

Non-metals form anions

26Writing formulasFive step rule1. Write the symbol.2.Write the charges.3. Cross over the charges from top to bottom.4. Remove the charge.5. Simplify the numbers.Formulas...

27Predicting Ionic Charges

Group 1:Lose 1 electron to form 1+ ionsH+Li+Na+K+28Predicting Ionic Charges

Group 2:Loses 2 electrons to form 2+ ionsBe2+Mg2+Ca2+Sr2+Ba2+29Predicting Ionic Charges

B3+Al3+Ga3+Group 3: Loses 3 electrons to form 3+ ions

30Predicting Ionic Charges

Neither! Group 13 elements rarely form ions.Group 4: Lose or gain 4 electrons?31Predicting Ionic Charges

N3-P3-As3-NitridePhosphideArsenideGroup 5: Gain 3 electrons to form 3- ions32Predicting Ionic Charges

O2-S2-Se2-OxideSulfideSelenideGroup 6: gain 2 electrons to Form 2- ions33Predicting Ionic Charges

F1-Cl1-Br1-FluorideChlorideBromideI1-IodideGroup 7: gain 1 electron to form 1- ion34Work for today...Chapter 5.51. Describe the alkali metals. 2. How are the alkali metals different from the alkali earth metals?3. Describe the noble gases.4. Describe the halogens.Chapter 5.6Do #s 1, 2, 3, 4Chapter 5.8Do #s 1,2,3,4,5,6

35Predicting Ionic Charges

Iron(II) = Fe2+Iron(III) = Fe3+Many Transition metals have more than one possible ionic charge36Predicting Ionic Charges

Zinc = Zn2+Silver = Ag+Some transition elements have only one possible charge37Writing Ionic Compound FormulasExample: Barium nitrate1. Write the formulas for the cation and anion, including CHARGES!Ba2+NO3-2. Check to see if charges are balanced. 3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced!( )238Writing Ionic Compound FormulasExample: Ammonium sulfate1. Write the formulas for the cation and anion, including CHARGES!NH4+SO42-2. Check to see if charges are balanced. 3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced! ( )239Writing Ionic Compound FormulasExample: Iron(III) chloride1. Write the formulas for the cation and anion, including CHARGES!Fe3+Cl-2. Check to see if charges are balanced. 3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced!340Writing Ionic Compound FormulasExample: Aluminum sulfide1. Write the formulas for the cation and anion, including CHARGES!Al3+S2-2. Check to see if charges are balanced. 3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced!2341Writing Ionic Compound FormulasExample: Magnesium carbonate1. Write the formulas for the cation and anion, including CHARGES!Mg2+CO32-2. Check to see if charges are balanced. They are balanced!42Writing Ionic Compound FormulasExample: Zinc hydroxide1. Write the formulas for the cation and anion, including CHARGES!Zn2+OH-2. Check to see if charges are balanced. 3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced! ( )243Writing Ionic Compound FormulasExample: Aluminum phosphate1. Write the formulas for the cation and anion, including CHARGES!Al3+PO43-2. Check to see if charges are balanced. They ARE balanced!44Naming Ionic Compounds(continued)-some metals form more than one cation-use Roman numeral in namePbCl2Pb2+ is cationPbCl2 = lead(II) chlorideRoman numeral is equal to the charge of the cationMetals with multiple oxidation states45

46Complex Ions (Polyatomic Ions)Mg 2+, I-, Li +, S2- are all called simple ions or monatomic ions

Complex, or polyatomic ions, are tightly bound groups of ions that behave as a unit and carry a charge. Example : sulfate ion. A sulfate ion is composed of 1 sulfur atom and 4 oxygen atoms. These 5 atoms together form a unit with a charge.SO4 2-

Recognizing complex ions is a key in naming chemical compounds and writing chemical formulas. Polyatomic Ion Rap...

47

Polyatomic Ions

Ammonium...NitratePermanganate. . ChlorateHydroxide.Cyanide.Sulfate...Carbonate.Chromate..Acetate..Phosphate.NH4+NO3-MnO4-ClO3-OH-CN-SO4 2 -CO32-CrO42-C2H3O2-PO43-48cobalt (III) carbonate Co2(CO3)3beryllium nitrate Be(NO3)2

Polyatomic tutorial...

Please do #s 1,2,3,4,6,7 on page 189 Chapter 5.9

49Section 5.11Molecular Compounds50Properties of Molecular CompoundsComposed of 2 or more non-metals Form covalent bonds in which the electrons are shared (not lost or gained friendlier!)Many are gases at room temperature, they do not conduct electricity and most are not soluble in water.Ionic and covalent bonds

51Uses Prefixes1 mono 2 di 3 tri 4 tetra 5 penta 6 hexa 7 hepta 8 octa 9 nona 10 deca Example: CCl4 carbon tetrachloride Try: 1. P2O5 2. N2O 3. ICl31. Diphosphorous pentaoxide 2. Dinitrogen monoxide 3. Iodine trichloride

Naming Molecular Compounds52Name TheseN2ONO2Cl2O7CBr4CO2BaCl2H2ODinitrogen monoxideNitrogen dioxideDichlorine heptoxideCarbon tetrabromideCarbon dioxideBarium chlorideDihydrogen monoxide53Write Formulas for TheseDiphosphorous pentoxideTetraiodine monoxideSulfur hexaflourideNitrogen trioxideCarbon tetrahydridePhosphorous trifluorideAluminum chlorideP2O5I4OSF6NO3CH4PF3AlCl354To illustrate how the bonding occurs between two non-metals, Lewis Dot Structure is used.Only the valence electrons are used and each valence electron is represented by a dotWrite the symbol for the element, then draw dots around the symbol to represent the number of valence electrons. Electrons are placed one on each side going around the symbol.

Covalent Bonding 55

56It is only the electrons in the outermost orbits that can form bonds.

58Diatomic molecules are molecules that have only 2 atoms of the same element.They prefer to share electrons in covalent bonds than to exist on their own.ElementChemical SymbolFormula and StatehydrogenHH 2 (g)oxygenOO 2 (g)(g) = gasnitrogenNN 2 (g)(l) = liquidfluorineFF 2 (g)(s) = solidchlorineClCl 2 (g)bromineBrBr 2 (g) iodineII 2 (g)I have no bright or clever friends59There is no need to balance the charges (there are no ions remember!)Simply look at the prefix used in the name to determine how many atoms of each element is present.Ex. Carbon tetrachloride C 1, Cl 4 CCl4Ex. Pentaphosphorous Trisulfide , P 5, S 3 P5S3Writing Chemical Formulas for Molecular Compounds60When using the prefixes to illustrate the number of atoms in the compound, the rules are clear;NEVER use the prefix mono on the first elementAll compounds , whether ionic or molecular, end in ideIf by adding the prefix you create a double vowel, drop the first for ease of pronunciation.

Please do the following questions on page 2041,2,3,4,5,661Acids and Bases

62AcidsAcids are sour-tasting, water soluble substances found in many common products.They are very reactive and good conductors of electricity. All acids contain hydrogen atoms in combined form and when dissolved in water they release H+.Examples of common acidsVinegar (acetic acid)Salad dressingCitric acidoranges, lemonsAcetylsalicylic acid (ASA)AspirinSulfuric acidcar batteries Carbonic acidcarbonated drinks

63AcidsA dilute acid has lots of water and a small amount of acidA concentrated acid has lots of acid and not much water so must be handled carefullyA strong acid releases lots of H+A weak acid releases fewer H+64Lesson 2Write bomb equation NaHCo3 + CH3CooH -> Ch3CooNa +H20 + CO2Aim to work out how to make the canister fly furthest. Can alter the amount of acid and trajectory angle. How do you ensure fair test. Discussion.Expt film canister and bicarbonate explosions who can get the furthest, FAIR TEST angle of trajectory, amount acidBasesBases are bitter tasting, water soluble and feel slippery.They release hydroxide ions (OH-) when dissolved in water and are good conductors of electricity.

Examples of basesSodium hydroxidedrain cleanerPotassium hydroxidesoap, cosmeticsAluminum hydroxideantacidsSodium bicarbonatebaking soda

65In our home we often use bases to clean things Bleach and toothpaste

Some things are not acids or bases: we say that they are neutraleg. water

66Lesson 3Kids write from board Acid and base are opposite one neutralises the otherToothpaste neutralises acids formed by plaque bacteria, bee sting (formic acid baking soda neutralise)Bases which are soluble in water are called alkalis (feel soapy as they turn oils on hands into soap)EXPT make soap see H/ORecognizing acids and bases from their chemical formulas1. Acids are easy! They begin with hydrogen H2SO4 sulfuric acid, or H2CO3 carbonic acid.2. Bases are more difficult. They usually contain OH but not always, ex. NaOH. An exception would be NaHCO3 (baking soda) is a base because it reacts with water to produce Oh-.QuestionsWhat is the most important acid in the chemical industry?What is it used for?#3 on page 295

67Chapter 6 - Understanding Chemical ReactionsA word equation is one way of representing a chemical reaction. It tells you what reacts and what is produced. Word equations are written like this:reactants productsDO NOT COPY: When hot steel wool (iron) is put into a bottle of oxygen, there is a spectacular reaction and iron (III) oxide is produced. The word equation would be:iron+oxygeniron (III) oxide

68Write the word equation for the following example:

When zinc is added to hydrochloric acid, hydrogen and zinc chloride are produced.

Zinc + hydrochloric acid hydrogen + zinc chloride

Please do questions 2 and 3 on page 219696.5 Balancing Chemical EquationsA skeleton equation represents all chemicals by their formulas. Word Equationmethane + oxygen water + carbon dioxideSkeleton EquationCH4+O2H2O +CO2706.3 Conserving MassThe Law of Conservation of Mass states that in a chemical reaction, the total mass of the reactants is always equal to the total mass of the products.

71How to balance Equations:1. Determine the correct formulas and write the skeleton equation:Fe+O2Fe2O32. Count the number of atoms of each element in the reactants and products. (Polyatomic ions appearing unchanged on each side are counted as a single unit). Type of AtomReactantsProductsFe12O23

723. Balance the elements one at a time by using coefficients. The coefficient is a whole number that appears in front of the formula. When no coefficient is written, it is assumed to be 1. 4 Fe+3 O22 Fe2O3

73Always check to be sure that the equation is balanced.Type of AtomReactantsProductsFe44O66

5. Make sure all coefficients are in the lowest possible ratio. (Reduce if possible)74Hints:Never add extra compoundsNever change formulas (subscripts)If an element appears in only one compound on each side balance this one first.When one of the products or reactants is a free element (only one type of atom) balance this last.When you end up with an uneven number on one side and an even number on the other side you will have to double all of the coefficients to make them all even.

75Balancing Chemical EquationsSection 6.576Because we cannot change the chemical formulas of compounds in the reaction, we need to use coefficients to balance the number of atoms.Coefficients are numbers placed in front of the compound and apply to all elements in the compound (unlike subscripts which only apply to that element).77Equation typesWe began by writing word equationsIron + Oxygen Iron II oxideWriting chemical formulas based on the word equations is known as skeleton equations.Fe + O2 FeOBecause of the Law of Conservation of Mass, we now need to write a balanced equation.78Steps to balancing equationsCount the number of atoms of each type in the reactants and products.Fe + O2 FeO

Type of AtomReactantsProductsFe11O2179Multiply each of the formulas by the appropriate coefficient to balance the number of atoms. Re-write the equation.2Fe + O22 FeO

80TipsLook for larger molecules (ie polyatomic) or complex molecules and balance them first, especially if they appear on both sides.If you have an odd number on one side and an even number on the other, fix the odd side first.Al + O2 Al2 O3 , fix products firstLeave diatomic molecules and elements that appear more than once on the same side to the end.

816.7 Types of Reactions There are five main categories of chemical reactions:1. Combustion2. Synthesis3. Decomposition4. Single Displacement5. Double Displacement82Combustion the rapid reaction of a substance with O2 to produce compounds called oxides (often call this process burning).The fuel can be a variety of things but it is often a hydrocarbon (ex. gasoline) The formula for combustion of a hydrocarbon isC4 H10 +O2CO2+ H2 O + energy(C4H10 is Butane)

83The products of a combustion reaction are always carbon dioxide and water. (C4H10 is butane)

Skeleton...C4 H10+ O2 CO2+ H2 O + energy

Balanced ...

2C4 H10+13O2 8CO2+ 10H2 O + energy

84Synthesis ReactionsInvolves the combination of smaller atoms or compounds into larger compounds. (also known as combination reactions). They have the following general formula: A + B AB85If both reactants are elements then the reaction MUST be synthesis. Example: 2H2 + O2 2H2O

86Examples2Na + Cl2 => 2NaCl

2Al + 3Br2 => 2AlBr3

87Synthesis reactions sometimes involve joining two compounds into a larger one.

hydrogen chloride + ammonia ammonium chloride

HCl + NH3 NH4Cl88Decomposition Reactions

Involves the splitting of a large compound into smaller molecules or elements. They have the following general formula: AB A + B

If there is only 1 reactant then the reaction MUST be decomposition.Example: 2H2O2H2 + O289What types of Reactions are these? 1. H2CO3 CO2+ H2O2. 2Fe + O2 2FeO3. C10H8 + 12 O2 10 CO2 + 4 H2O

Answers:DecompositionSynthesisCombustion

90Please do the followingPage 235#s 1,2,3,4Single DisplacementThis is when one element trades places with another element in a compound. These reactions come in the general form of: A + BC ---> AC + BExample: Fe + CuSO4 => FeSO4 + Cu

The reactants MUST be an element and a compound92Single displacement can involve metals:Na + KCl K + NaCl

Single displacement can involve nonmetals:F2 + 2LiCl 2 LiF + Cl2Remember - If the single element is a nonmetal it will replace the nonmetal. If the single element is a metal it will replace the metal.

93Double DisplacementInvolves two elements replacing one another. The reactants must be compounds (usually happens in solution). The positive ions stay in the same position (A and C) and the negative ions change partners (B and D). The general formula is: AB + CD AD + CB

94NaOH + FeCl3

NaOH + FeCl3 Fe(OH)3 +NaCl

Pb(NO3)2 + 2 KI

Pb(NO3)2 + 2 KI PbI2 + 2 KNO3

95List what type the following reactions are: 1) NaOH + KNO3 --> NaNO3 + KOH 2) CH4 + 2 O2 --> CO2 + 2 H2O 3) 2 Fe + 6 NaBr --> 2 FeBr3 + 6 Na 4) CaSO4 + Mg(OH)2 --> Ca(OH)2 + MgSO4 5) Pb + O2 --> PbO2 6) Na2CO3 --> Na2O + CO2

961) double displacement 2) combustion 3) single displacement 4) double displacement 5) synthesis 6) decomposition97Please do the followingPage 241#s 1,2,3 Chemical reactions and balancing equations...Rates of reactionObjectivesTo understand that a chemical reaction involves collisions between particlesTo be able to describe the four factors which will affect the rate of a chemical reaction.

How do we make the reaction go faster?There are four things that we can change to make the reaction go faster.They are: TemperatureSurface areaConcentrationUsing a catalystTemperatureWhen we increase the temperature we give the particles energyThis makes them move faster This means they collide with other particles more oftenSo the reaction goes faster.Surface areaIf we make the pieces of the reactants smaller we increase the number of particles on the surface which can react.This makes the reaction faster.

The particles on the surface can react

When cut into smaller pieces the particles on the inside can reactConcentrationIf we make one reactant more concentrated (like making a drink of orange squash more concentrated)There are more particles in the same volume to reactSo the reaction goes faster.

There are less red particles in the same volume so there is less chance of a collisionThere are more red particles in the same volume so there is more chance of a collision so the reaction goes fasterUsing a catalystA catalyst is a chemical which is added to a reaction.It makes the reaction go faster.The catalyst does not get used up in the reaction.It gives the reaction the energy to get startedClick here ...to complete exercise 2Click here ...to complete exercise 3

Rates of reaction