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Unit II Physical Science I Chemistry. Chemistry Terms Matter - anything that has mass and takes up space Chemistry - is the study of matter, its properties.

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Presentation on theme: "Unit II Physical Science I Chemistry. Chemistry Terms Matter - anything that has mass and takes up space Chemistry - is the study of matter, its properties."— Presentation transcript:

1 Unit II Physical Science I Chemistry

2 Chemistry 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

3 Pure Chemistry - describing known substances and discovering new compounds for research purposes. Pure 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. Applied Chemistry – the search for uses for chemical substances. Modern society demands chemistry understanding. Ex. technology; government.Ex. technology; government.

4 Mass- The amount of matter an object contains in grams (g). Mass- The amount of matter an object contains in grams (g). States of Matter– 3 physical states: States of Matter– 3 physical states: 1)Solid definite volume/shape 2)Liquid definite volume/indefinite shape 3)Gas indefinite volume/shape (aq)=aqueous; dissolved in H 2 O

5 Physical Property- a characteristic of a substance; can be observed without changing into a new substance. Physical 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.Ex. State of matter, hardness, melting point, boiling point, odour, solubility colour, malleability, ductility, brittleness, conductivity.

6 Physical Change- a change in state of a substance (no new substance formed). Physical 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)Ex. melting (s to l); evaporation/boiling (l to g); condensation (g to l); sublimation (s to g) H 2 O (s) H 2 O (l) heat

7 Chemical Property- a characteristic behaviour of a substance that occurs when a substance changes into a new substance. Chemical Property- a characteristic behaviour of a substance that occurs when a substance changes into a new substance. Ex.Ex. 2 Mg (s) +O 2(g) 2 MgO (s) Mg ribbon + light energy

8 Chemical Change- a change in which one or more NEW substances are formed. Chemical Change- a change in which one or more NEW substances are formed. Ex.Ex. coal combustion C (s) + O 2(g) 2 CO 2(g) + heat rusting 4 Fe (s) + 3 O 2(g) Fe 2 O 3(g)

9 Indicators of Chemical Change – Indicators of Chemical Change – new colour new colour heat/light given off heat/light given off Bubbles of gas Bubbles of gas Precipitate (solid) formation Precipitate (solid) formation Change is difficult to reverse Change is difficult to reverse

10 Mixture – contains 2 or more pure substances. Mixture – contains 2 or more pure substances. Two Types: Two Types: Homogeneous Mixture- aka “solution”- have only one visible phase throughout.Homogeneous Mixture- aka “solution”- have only one visible phase throughout. ex. air, apple juice, salt water ex. air, apple juice, salt water Heterogeneous Mixture- contain 2 or more visible components or phasesHeterogeneous Mixture- contain 2 or more visible components or phases ex. soil, soup ex. soil, soup

11 Pure Substance – made up of only one type of atom or atom combination. Pure Substance – made up of only one type of atom or atom combination. (Ex. O 2, H 2 O) Stays the same in response to physical change. Two Types: Compounds and Elements

12 Compounds - pure substances that contain two or more different elements in a fixed proportion ie., CO 2, H 2 O, C 6 H 12 O 6 and NaCl Can be broken down to elements via chemical means. Ex. 2 NaCl (l) 2 Na (l) + Cl 2 (g) electricity

13 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 phosphorus Element Symbols are always written with the first letter uppercase and the second letter lowercase. Element Symbols are always written with the first letter uppercase and the second letter lowercase. Ex. Au, Mg, ArEx. Au, Mg, Ar Element Names are always written in lowercase letters. Element Names are always written in lowercase letters.

14 Diatomic Molecules – There are 7 elements that are diatomic gases in their natural state. Diatomic Molecules – There are 7 elements that are diatomic gases in their natural state. These are: H 2 O 2 F 2 Br 2 I 2 N 2 Cl 2 These are: H 2 O 2 F 2 Br 2 I 2 N 2 Cl 2 Also P 4 and S 8 Also P 4 and S 8 How can we remember these? How can we remember these? HOFBrINCl PS! (or an upside down “L” on the periodic table).HOFBrINCl PS! (or an upside down “L” on the periodic table).

15 Matter MixtureHeterogeneousHomogeneousPure SubstanceCompound Element atom Matter Flow Chart (Ionic, Molecular, Acids) (Metals, Nonmetals) (solutions)

16 Reactants – starting materials. Reactants – starting materials. Products – new substances formed. Products – new substances formed. Chemical Reaction Chemical Reaction ReactantsProducts “go to form”

17 Periodic Table Mid 1800s- 65 known elements. Mid 1800s- 65 known elements. Began to recognize patterns after recording reactivity, masses, etc. Began to recognize patterns after recording reactivity, masses, etc.

18 Dmitri Mendeleev ( ) Wrote out elements in order of increasing atomic mass, result was a table. Wrote out elements in order of increasing atomic mass, result was a table. “periodic” table- “periodic” meaning repeating patterns and properties. “periodic” table- “periodic” meaning repeating patterns and properties. We now organize the periodic table according to atomic number We now organize the periodic table according to atomic number Also organized according to # of electrons (e - ) in atoms of each element. Also organized according to # of electrons (e - ) in atoms of each element.

19 Periodic Table- A Review It is designed to arrange elements in a pattern that helps us predict properties and bonding patterns of elements. 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. Elements are organized by Atomic Number and Number of Electrons. The periodic Table is arranged in rows and columns. The periodic Table is arranged in rows and columns.

20 Period: horizontal row (7 in total) Period: horizontal row (7 in total) : atomic mass and atomic number increase( )from L to R. Group/Family: vertical columns (18) Group/Family: vertical columns (18) :Elements of the same group have similar but not identical properties. :Elements of the same group have similar but not identical properties. Some groups have species names: Some groups have species names: Group 1- Alkali Metals Group 17- Halogens Group 2- Alkaline Earths Group 18- Noble Gases Lanthanides (rare earth)Lanthanides (rare earth) ActinidesActinides

21 Groups have 2 numbering systems: Groups have 2 numbering systems: New Group 1-18New Group 1-18 Old Roman Numerals/LettersOld Roman Numerals/Letters IA-VIIIA - Representative Elements IA-VIIIA - Representative Elements IB-VIIIB - Transition Elements. IB-VIIIB - Transition Elements.

22 Metals and Nonmetals Metals and Nonmetals Li 3 He 2 C6C6 N7N7 O8O8 F9F9 Ne 10 Na 11 B5B5 Be 4 H1H1 Al 13 Si 14 P 15 S 16 Cl 17 Ar 18 K 19 Ca 20 Sc 21 Ti 22 V 23 Cr 24 Mn 25 Fe 26 Co 27 Ni 28 Cu 29 Zn 30 Ga 31 Ge 32 As 33 Se 34 Br 35 Kr 36 Rb 37 Sr 38 Y 39 Zr 40 Nb 41 Mo 42 Tc 43 Ru 44 Rh 45 Pd 46 Ag 47 Cd 48 In 49 Sn 50 Sb 51 Te 52 I 53 Xe 54 Cs 55 Ba 56 Hf 72 Ta 73 W 74 Re 75 Os 76 Ir 77 Pt 78 Au 79 Hg 80 Tl 81 Pb 82 Bi 83 Po 84 At 85 Rn 86 Fr 87 Ra 88 Rf 104 Db 105 Sg 106 Bh 107 Hs 108 Mt 109 Mg 12 Ce 58 Pr 59 Nd 60 Pm 61 Sm 62 Eu 63 Gd 64 Tb 65 Dy 66 Ho 67 Er 68 Tm 69 Yb 70 Lu 71 Th 90 Pa 91 U 92 Np 93 Pu 94 Am 95 Cm 96 Bk 97 Cf 98 Es 99 Fm 100 Md 101 No 102 Lr 103 La 57 Ac   METALS Nonmetals Metalloids

23 Types of Elements The staircase line divides the elements into two major categories: the metals and the nonmetals The ratio of metals to nonmetals is about 4:1 The Metals Metals 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).

24 The Nonmetals Nonmetals are dull and are very poor conductors or nonconductors of electricity. Nonmetals are dull and are very poor conductors or nonconductors of electricity. The solid nonmetals are brittle. The solid nonmetals are brittle. As a group, the nonmetals exhibit the three states of matter at room temperature. 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.

25 The location of hydrogen in the periodic table is unusual. The 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). 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. Due to the fact that hydrogen has some metallic properties in addition to nonmetallic properties. 2 groups: Alkali Metals and Halogens (1 and 17). 2 groups: Alkali Metals and Halogens (1 and 17).

26 The Metalloids The metalloids are elements that possess both metallic and nonmetallic properties. The 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). 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. Metalloids are also known as the semimetals.

27 Representative Elements The representative elements illustrate the entire range of the properties of the elements. The representative elements illustrate the entire range of the properties of the elements. [Group 1, 2, 13-18]. [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. Sometimes known as the group A elements, they are organized into chemical families based on their specific chemical and physical properties.

28 The Transition Elements The transition elements are all metals. 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. 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: Inner Transition Elements: (Lanthanides, Actinides) Same as transition, but removed from main table as a matter of convenience in organizing table.

29 Elements in the periodic table are organized based on shared properties. Elements in the periodic table are organized based on shared properties. Metalloids (staircase)

30 Molecular Substances Exist as groups of atoms called molecules Exist as groups of atoms called molecules Molecules are substances composed of nonmetallic elements Molecules are substances composed of nonmetallic elements Methane – CH 4 Nitrogen – N 2

31 You must memorize these Noble Gases (group VIIIA or 18) HeHelium NeNeon ArArgon KrKrypton XeXenon RnRadon Mono-atomic molecular elements Mono-atomic molecular elements

32 Do you know this one? neon Ne

33 Diatomic molecular Elements All have two identical atoms All have two identical atoms O = iodine eg I2I2

34 How about this one? nitrogen N2N2

35 Memorize the diatomic molecular elements Hydrogen H2H2H2H2 Oxygen O2O2O2O2 Fluorine F2F2F2F2 Bromine Br 2 Iodine l2l2l2l2 Nitrogen N2N2N2N2 Chlorine Cl 2 Just remember the famous chemist Dr. HOFBrINCl

36 ozone O3O3O3O3 Sulfur S8S8S8S8 Phosphorus(red) P4P4P4P4 Phosphorus(white) P 10 remember the…… Molecular Elements

37 Molecular Compounds Consist of two or more nonmetallic elements Consist of two or more nonmetallic elements 2 types of molecular compounds 1. Binary molecular compounds 2. Ternary molecular compounds

38 Binary vs ternary Molecular Compounds Type of Compound Molecular formula name BinaryH2OH2Owater BinaryH2O2H2O2 hydrogen peroxide BinaryNH 3 ammonia BinaryCH 4 methane TernaryCH 3 OHmethanol TernaryC 2 H 5 OHethanol TernaryC 12 H 22 O 11 sucrose Memorize the names and formulas of common molecular substances as per the chemistry facts sheet

39 Binary Molecular Compounds Composed of 2 nonmetals Composed of 2 nonmetals CO 2, CCl 4, BF 3 are examples CO 2, CCl 4, BF 3 are examples Many are identified by common names Many are identified by common names ie., water = H 2 O ammonia = NH 3 ie., water = H 2 O ammonia = NH 3 System for naming and writing formulas established by I.U.P.A.C. System for naming and writing formulas established by I.U.P.A.C. International Union for Pure and Applied Chemistry International Union for Pure and Applied Chemistry

40 Requires a system of prefixes: Requires a system of prefixes:Numberprefix 1mono 2di 3Tri 4Tetra 5Penta 6hexa 7Hepta 8Octa 9nona 10deca This table is on your chemistry facts page

41 RULES FOR NAMING BINARY MOLECULAR COMPOUNDS Write the name of the first element of the formula in full. Write the name of the first element of the formula in full. Shorten the name of the second element and add the “ide” ending. 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. Use prefixes to indicate the number of atoms of each element in the molecular formula. The prefix mono on the first name is optional. The prefix mono on the first name is optional.

42 Write the IUPAC name for CCl 4 Write the IUPAC name for CCl 4 The first element is C. The first element is C. Its full name is carbon. Its full name is carbon. The second element is chlorine. The second element is chlorine. Its name is shortened to “chlor”, and the suffix “ide” is added to give chloride. 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: The prefix mono (1) is added to carbon, and the prefix tetra (4) is added to chloride to give the name: monocarbon tetrachloride. monocarbon tetrachloride. The prefix mono can be omitted from the first element name to give: The prefix mono can be omitted from the first element name to give: carbon tetrachloride. Sample

43 Name N 2 O 4 Name N 2 O 4 Nitrogen oxide Nitrogen oxide Dinitrogen tetraoxide (tetroxide) Dinitrogen tetraoxide (tetroxide) Sample 2

44 U do Name: Name: B 2 H 6 B 2 H 6 Diboron hexahydride Diboron hexahydride

45 Chemical Bonding Molecular compounds like B 2 H 6 are held together by bonds. Molecular compounds like B 2 H 6 are held together by bonds. A chemical bond is the force of attraction between atoms. A chemical bond is the force of attraction between atoms. In molecular compounds the bond is the force of attraction occurs between nonmetallic elements In molecular compounds the bond is the force of attraction occurs between nonmetallic elements This type of bond is called a covalent bond This type of bond is called a covalent bond

46 Atomic Theory Atom – the smallest particle of an element that retains the properties of that element. Atom – 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 Atoms are thought to be composed of negatively charged particles called electrons and a dense central region called the nucleus

47 Within the nucleus are found positively charged particles called protons and neutral particles known as neutrons Within the nucleus are found positively charged particles called protons and neutral particles known as neutrons Electrons are believed to exist a specific distances from the nucleus called energy levels Electrons are believed to exist a specific distances from the nucleus called energy levels

48 Electron Energy Level Diagrams Representative Elements Show electron arrangements within an atom’s energy levels. Show electron arrangements within an atom’s energy levels. We can predict them using the following: 1. Atomic number 2. Period number 3. Group number 4. Electrons per energy level

49 Electron Energy Level Diagrams Representative Elements Atomic number Atomic # represents the number of protons in the nucleus of an atom. Atomic # represents the number of protons in the nucleus of an atom. the # protons = # electrons. the # protons = # electrons. Example: Carbon has atomic # 6 which means C has 6 protons and 6 electrons) Example: Carbon has atomic # 6 which means C has 6 protons and 6 electrons) 6+ 6 electrons nucleus

50 Electron Energy Level Diagrams Representative Elements Period Number Period Number tells us how many energy levels contain electrons tells us how many energy levels contain electrons Eg Carbon is in the second row of the periodic table thus it is in period 2 and has electrons in 2 energy levels. Eg Carbon is in the second row of the periodic table thus it is in period 2 and has electrons in 2 energy levels.Carbon 2nd 6+ 1st

51 Electron Energy Level Diagrams Group # (family number) The group # tells us about electrons in the outer energy level of an atom (valence electrons) The group # tells us about electrons in the outer energy level of an atom (valence electrons)

52 Electron Energy Level Diagrams Representative Elements We will deal with the representative elements only We will deal with the representative elements only (for groups 13 and above valence electrons = the last digit): (for groups 13 and above valence electrons = the last digit): 13, 14, 15, 16, 17, 18 13, 14, 15, 16, 17, 18 C has 4 valence electrons since it is group 14 2nd 1st 6+ 4e -

53 Electron Energy Level Diagrams Representative Elements Period #of elements in the period Energy level max # of e

54 Electron Energy Level Diagrams Representative Elements 2nd 1st 6+ 4e - 2e -

55 Electron Energy Level Diagrams Representative Elements Example: Draw an electron energy level diagram for an atom of aluminum Example: Draw an electron energy level diagram for an atom of aluminum 13+ Atomic number 13 Period 3 Group 13 3e - 8e - 2e - Fill in the nonvalence electrons with the maximums per energy level

56 Energy level diagrams - ions Recall the noble gases are unreactive Recall the noble gases are unreactive All noble gases have filled valence energy levels All noble gases have filled valence energy levels

57 atoms react by changing the number of electrons to try and get the same structure of the nearest noble gas atoms react by changing the number of electrons to try and get the same structure of the nearest noble gas In other words, atoms either gain or lose electrons to become stable In other words, atoms either gain or lose electrons to become stable Metals lose electrons to have the same electron arrangement as the nearest noble gas Metals lose electrons to have the same electron arrangement as the nearest noble gas Nonmetals gain electrons to have an electron arrangement of the nearest noble gas. Nonmetals gain electrons to have an electron arrangement of the nearest noble gas.

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60 Ions Metals lose electrons to form positive ions called cations Metals lose electrons to form positive ions called cations Nonmetals gain electrons to form negative ions called anions Nonmetals gain electrons to form negative ions called anions Both ions have noble gas stability Both ions have noble gas stability

61 Ionic compounds Composed of oppositely charged ions Composed of oppositely charged ions Held together by ionic bonds Held together by ionic bonds 3 categories of ionic compounds : 3 categories of ionic compounds : 1)Binary ionic compounds 1)Binary ionic compounds simple ions (only single charges)simple ions (only single charges) multivalent ions (more than one charge)multivalent ions (more than one charge) 2) Polyatomic ions (complex ions) 2) Polyatomic ions (complex ions) 3) Hydrates 3) Hydrates

62 Binary ionic compounds Binary ionic compounds are composed of a metal ion (+) and non-metal ion (-). Binary ionic compounds are composed of a metal ion (+) and non-metal ion (-). Naming binary ionic compounds: 1. Name the cation (+) by writing the full name of the metal. 2. Name the anion (-) by shortening the name of the element and add the -ide ending.

63 Binary ionic compounds NaCl sodium and chlorine NaCl sodium and chlorine sodium chloride sodium chloride CaF 2 calcium and fluorine CaF 2 calcium and fluorine calcium fluoride calcium fluoride K 2 O potassium and oxygen K 2 O potassium and oxygen potassium oxide potassium oxide IMPORTANT: Do Not use prefixes - they are for molecular compounds (two non-metals) IMPORTANT: Do Not use prefixes - they are for molecular compounds (two non-metals)

64 Rules for Writing Binary Ionic Formulas: Write down the symbols of the ions involved. Write down the symbols of the ions involved. Determine the lowest whole number ratio of ions that will give a net charge of zero. Determine the lowest whole number ratio of ions that will give a net charge of zero. Write the formula removing all charges. Write the formula removing all charges.

65 Write a chemical formula for a compound that contains Calcium ions and Bromide ions. Write down the symbols of the ions involved Write down the symbols of the ions involved Calcium is group IIA, Ca 2+ Calcium is group IIA, Ca 2+ Bromide is group VIIA, Br – Bromide is group VIIA, Br – Determine the lowest whole number ratio of ions that will give a net charge of zero. Use the crossover method Determine the lowest whole number ratio of ions that will give a net charge of zero. Use the crossover method Ca 2+ Br – Ca Br 2 Sample

66 Binary 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 these Sn2+ is called tin (II) and Sn4+ is called tin (IV)

67 Stock System Example too! Cu + is copper (I) Example too! Cu + is copper (I) Cu 2+ is copper (II) Cu 2+ is copper (II) The periodic table lists the ions that have stock names. The periodic table lists the ions that have stock names.

68 Ion Stock name Cu + Copper (I) Cu 2+ Copper (II) Fe 2+ Iron (II) Fe 3+ Iron (III) Sn 2+ Tin (II) Sn 4+ Tin (IV) Pb 2+ Lead (II) Pb 4+ Lead (IV)

69 Stock System Egg Sample: Write the chemical formula for iron(II) chloride. Egg Sample: Write the chemical formula for iron(II) chloride. 1. Write the symbols of the ions involved 2. Iron (II) (the roman numeral tells us it has a 2+ charge) Fe Chloride (has a 1- charge) Cl – 4. Determine the lowest whole number ratio of ions that will give a net charge of zero. Use the criss cross method: Fe 2+ Cl – FeCl 2

70 Write formulas for: Write formulas for: Titanium (IV) fluoride Titanium (IV) fluoride Titanium (II) fluoride Titanium (II) fluoride Nickel (II) oxide Nickel (II) oxide Lead (IV) sulfide Lead (IV) sulfide

71 Naming 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 stable polyatomic ion (complex ion) - is a group of atoms that are covalently bonded which then gain or lose electrons to become stable Example: Example: The ammonium ion, NH 4 +, consists of one nitrogen atom and four hydrogen atoms which as a group have lost one electron. The ammonium ion, NH 4 +, consists of one nitrogen atom and four hydrogen atoms which as a group have lost one electron.

72 Table of Complex Ions

73 Writing Chemical Formulas for Compounds with Polyatomic Ions: write the cation symbol first and the anion symbol last. write the cation symbol first and the anion symbol last. balance the charges by providing the appropriate numerical subscript for each ion. balance the charges by providing the appropriate numerical subscript for each ion.

74 Write the a chemical formula for each compound: Write the a chemical formula for each compound: magnesium chlorate magnesium chlorate Mg 2+ ClO 3 - Mg 2+ ClO 3 - put brackets around the complex ion put brackets around the complex ion Mg 2+ (ClO 3 ) – criss cross the charges criss cross the charges Mg (ClO 3 ) 2 iron(III) sulfate iron(III) sulfate Fe 2 (SO 4 ) 3 Fe 2 (SO 4 ) 3

75 Naming Ionic Compounds Ionic Hydrates An ionic hydrate is a compound that decomposes upon heating to release water An ionic hydrate is a compound that decomposes upon heating to release water Water is part of its crystalline structure. Water is part of its crystalline structure. sample CuSO 4 ●5H 2 O is copper(II)sulfate pentahydrate

76 Each ionic hydrate has two parts to its name: cobalt (II) chloride cobalt (II) chloride Ionic salt A number of molecules of water dihydrate CoCl 2 2 H 2 O● A separator

77 U do zinc sulfate heptahydrate zinc sulfate heptahydrate potassium sulfate decahydrate potassium sulfate decahydrate nickel (II) nitrate tetrahydrate nickel (II) nitrate tetrahydrate

78 Acids – hydrogen compounds All are hydrogen compounds dissolved in water All are hydrogen compounds dissolved in water Acids can be simply defined as substances that release hydrogen ions (H+) in water Acids can be simply defined as substances that release hydrogen ions (H+) in water Substances dissolved in water are denoted by a subscript (aq) written after their formula Substances dissolved in water are denoted by a subscript (aq) written after their formula Eg. HCl (aq) Eg. HCl (aq) Acids turn blue litmus red Acids turn blue litmus red

79 Rules for Naming Acids: name the hydrogen compound as if it were an ionic compound. name the hydrogen compound as if it were an ionic compound. (all of these compounds should end in - ide, -ate, or -ite.)(all of these compounds should end in - ide, -ate, or -ite.) depending on the ending convert the ionic name to the acid name. depending on the ending convert the ionic name to the acid name. Ionic nameacid name hydrogen _______ide → hydro _____ic acid hydrogen _______ide → hydro _____ic acid hydrogen _______ate → _________ ic acid hydrogen _______ate → _________ ic acid hydrogen _______ite → ________ous acid hydrogen _______ite → ________ous acid

80 Rule #1: hydrogen…ide If the aqueous hydrogen compound begins with “hydrogen” and ends in “ide”, then: If the aqueous hydrogen compound begins with “hydrogen” and ends in “ide”, then: Replace hydrogen with hydro and.. Replace hydrogen with hydro and.. replace the “ide” ending of the anion with ic acid replace the “ide” ending of the anion with ic acid Example: HCl (aq) Example: HCl (aq) Hydrogen chloride → hydrochloric acid Hydrogen chloride → hydrochloric acid

81 Rule #2: hydrogen…..ate : If the aqueous hydrogen compound begins in “hydrogen” and ends in “ate” then: If the aqueous hydrogen compound begins in “hydrogen” and ends in “ate” then: drop the name hydrogen (do not replace it) drop the name hydrogen (do not replace it) replace the “ate” ending of the anion with -ic acid replace the “ate” ending of the anion with -ic acid Example: HClO 3 (aq) Example: HClO 3 (aq) hydrogen chlorate → chloric acid hydrogen chlorate → chloric acid

82 Rule #3: hydrogen…ite If the aqueous hydrogen compound begins in “hydrogen” and ends in “ite” then: If the aqueous hydrogen compound begins in “hydrogen” and ends in “ite” then: drop the name “hydrogen” (do not replace it) drop the name “hydrogen” (do not replace it) replace the “ite” ending with -ous acid replace the “ite” ending with -ous acid Example: HNO 2 (aq) Example: HNO 2 (aq) hydrogen nitrite → nitrous acid hydrogen nitrite → nitrous acid

83 Bases Bases are substances that behave in opposition to acids. Bases are substances that behave in opposition to acids. ionic compounds that contain the hydroxide ion (OH-). ionic compounds that contain the hydroxide ion (OH-). Sodium hydroxide – NaOH (aq) Sodium hydroxide – NaOH (aq) Sample Sample

84 Properties of Bases: turn red litmus blue turn red litmus blue neutralize acids neutralize acids have high pH (> 7) have high pH (> 7) form slippery solutions form slippery solutions tend to have a bitter taste tend to have a bitter taste pH scale

85 Chemical Change communicated in sentence form or as chemical equations. communicated in sentence form or as chemical equations.

86 Chemical equations have four parts: 1 chemical formulas 2 subscripts for states of matter (s) solid (s) solid (l) liquid (l) liquid (g) gas (g) gas (aq) aqueous - dissolved in water (aq) aqueous - dissolved in water 3 numerical coefficients indicates how many atoms/molecules are involved indicates how many atoms/molecules are involved 4 reaction symbols the "+" sign on the reactants (left) side is read as "reacts with" the "+" sign on the reactants (left) side is read as "reacts with" the arrow ( → ) is read as "to produce" the arrow ( → ) is read as "to produce" the "+" sign on the products (right) side is read as "along with". the "+" sign on the products (right) side is read as "along with".

87 Chemical Equations Two molecules of diesel fuel react with 49 molecules of oxygen to produce 32 molecules of carbon dioxide and 34 molecules of water. Two molecules of diesel fuel react with 49 molecules of oxygen to produce 32 molecules of carbon dioxide and 34 molecules of water.

88 Evidence for Chemical Change: Chemical changes involve changes in make up - new substances are formed with new properties Chemical changes involve changes in make up - new substances are formed with new properties Physical changes involve changes in state without a change in make up. Physical changes involve changes in state without a change in make up.

89 Evidence of Chemical Change 4 indicators of chemical reaction: 4 indicators of chemical reaction: 1. energy change 2. colour change 3. precipitate formation 4. gas formation

90 1. a rock warmed by the sun all day loses its heat at night 2. milk goes sour when left out of the fridge 3. bubbles form in a glass of cold water as it warms 4. bubbles and steam rise out of a kettle of boiling water 5. paint dries on a hot day.

91 The 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. 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 Lavoisier Antoine Lavoisier placed mercury(II) oxide powder (a red powder) in a test tube, sealed it, and then weighed it carefully placed mercury(II) oxide powder (a red powder) in a test tube, sealed it, and then weighed it carefully

92 heated it and observed that the red powder gradually changed into a grey liquid heated 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 changed reweighed the sealed tube after the reaction was complete and observed that its mass had not changed opened the tube and noticed a rapid release of a gas which was later learned to be oxygen. The grey liquid was mercury metal. opened the tube and noticed a rapid release of a gas which was later learned to be oxygen. The grey liquid was mercury metal.

93 Balancing Chemical Equations All representations of a chemical change must reflect the law of conservation of mass All representations of a chemical change must reflect the law of conservation of mass Chemical equations must obey the law of conservation of mass Chemical equations must obey the law of conservation of mass The number of atoms of each element must be the same on both sides of the equation The number of atoms of each element must be the same on both sides of the equation For this reason all chemical equations we write must be balanced. For this reason all chemical equations we write must be balanced.

94 Balancing Chemical Equations Mercury(II)oxide forms mercury and oxygen Mercury(II)oxide forms mercury and oxygen Reactants Products Reactants Products HgO (s) → Hg (l) + O 2(g) HgO (s) → Hg (l) + O 2(g) 1 Hg 1 Hg 1 Hg 1 Hg 1O 2 O equation is unbalanced 1O 2 O equation is unbalanced 2HgO (s) → 2 Hg (l) + O 2(g) 2HgO (s) → 2 Hg (l) + O 2(g) 2 Hg 2 Hg 2 Hg 2 Hg 2O 2 O equation is balanced 2O 2 O equation is balanced 2HgO (s) → 2 Hg (l) + O 2(g) 2HgO (s) → 2 Hg (l) + O 2(g) sample


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