Presumed Knowledge Chemistry PDF

Presumed Knowledge Chemistry Welcome to Chemistry Lecturer: Dr. Damien Igoe Copyright notice COMMONWEALTH OF AUSTRALIA Copyright Regulations 1969 WARNING This material has been reproduced and communicated to you by or on behalf of the University of New South Wales pursuant to Part V B of the Copyrig...

Presumed Knowledge Chemistry Welcome to Chemistry Lecturer: Dr. Damien Igoe Copyright notice COMMONWEALTH OF AUSTRALIA Copyright Regulations 1969 WARNING This material has been reproduced and communicated to you by or on behalf of the University of New South Wales pursuant to Part V B of the Copyright Act 1968 (the Act). The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice. After completing the extended course, students should be able to: identify common laboratory equipment understand the importance of safe practice in the laboratory recall the chemical symbols and names of the first 36 elements in the periodic table describe Z, atomic number as a unique identifier of an element define allotropes and explain their similarities and differences distinguish between metallic and non-metallic elements in terms of physical properties locate an element in terms of its group, period and atomic number in the periodic table differentiate between atoms/molecules/elements/allotropes differentiate between molecular compounds and ionic compound After completing the extended course, students should be able to: identify the light metal, non-metal, transition metal, metalloid, actinide and lanthanide zones of the periodic table, (and recall their common properties) identify the members of the alkali metals, alkaline earth, halogen and noble gas families, (and recall their common properties). locate an element in terms of its group, period and atomic number in the periodic table recall the trends of atomic radii and metallic properties across a period determine the number of significant figures in a measurement apply the rules for significant figures in calculations express any number in correct scientific notation Unit 1: Course Overview and Significant Figures SYLLABUS SUMMARY: Course format Text books/Moodle Assessment scheme Laboratory program Scope of chemistry Course Format – Instructional Components Formal instruction:COMPULSORY 2 hours of lectures each week (1 hour each) 1.5 hours of tutorials each week. Face to face and online labs (not every week – to be advised) Informal instruction: CONSULTATIONS (optional) and STUDY CLUB (optional) If you need additional help with the Chemistry coursework… Ask questions in Tutorials Consultations and Study Club Text Books There is NO set text book for the course: Electronic copies of the student learning guide is available on Moodle Some useful texts: Foundations of College Chemistry (14th ed) by Hein and Arena, Wiley and Sons, 2014 Chemistry (2nd ed) by Blackman, Bottle, Schmid, Mocerino and Wille, Wiley and Sons, 2012. The Scope of Chemistry Chemical Formulae and Reactions Stoichiometry (moles) Acids, Bases and Salts Atoms and Trends in the Periodic Table Matter and Physical Properties Thermochemistry CHEMISTRY Electrolytes Redox and Electric Cells Organic Chemistry Chemical Bonding Equilibrium Unit 2: Measurement and significant figures After completing this block, students should be able to: identify common laboratory equipment understand the importance of safe practice in the laboratory determine the number of significant figures in a measurement apply the rules for significant figures in calculations express any number in correct scientific notation recall the chemical symbols and names of the first 36 elements in the periodic table describe Z, atomic number as a unique identifier of an element distinguish between metallic and non-metallic elements in terms of physical properties locate an element in terms of its group, period and atomic number in the periodic table identify the light metal, non-metal, transition metal, metalloid, actinide and lanthanide zones of the periodic table, (and recall their common properties) identify the members of the alkali metals, alkaline earth, halogen and noble gas families, (and recall their common properties). locate an element in terms of its group, period and atomic number in the periodic table recall the trends of atomic radii and metallic properties across a period differentiate between atoms/molecules/elements/allotropes define allotropes and explain their similarities and differences differentiate between molecular compounds and ionic compounds Safety in the laboratory Know the rules: wear safety glasses (goggle) wear a lab coat wear covered shoes Know the risks: read the safety information for the chemicals used AND the chemical produced Know the lab the eye wash station the fire blanket the broken glass procedure Ask for help if you are unsure Lab equipment – glass ware beakers conical flask (Erlenmeyer flask) test-tube measuring cylinder watch glass stirring rod burette volumetric flask Lab equipment test-tube rack wash bottle squash pipette tripod gauze heat-proof mat Bunsen burner balance water-bath filter funnel metal tongs clay triangle retort stand boss-head clamp evaporating basin thermometer Unit 2: Measurement and significant figures After completing this block, students should be able to: identify common laboratory equipment understand the importance of safe practice in the laboratory determine the number of significant figures in a measurement apply the rules for significant figures in calculations express any number in correct scientific notation recall the chemical symbols and names of the first 36 elements in the periodic table describe Z, atomic number as a unique identifier of an element distinguish between metallic and non-metallic elements in terms of physical properties locate an element in terms of its group, period and atomic number in the periodic table identify the light metal, non-metal, transition metal, metalloid, actinide and lanthanide zones of the periodic table, (and recall their common properties) identify the members of the alkali metals, alkaline earth, halogen and noble gas families, (and recall their common properties). locate an element in terms of its group, period and atomic number in the periodic table recall the trends of atomic radii and metallic properties across a period differentiate between atoms/molecules/elements/allotropes define allotropes and explain their similarities and differences differentiate between molecular compounds and ionic compounds Assumed Knowledge The following are covered in the Extended Physics course: SI units and prefixes scientific notation For example: 0.00000000658 g = 6.58  10-9 g = 6.58 ng Measurement The last digit in any measurement is uncertain it is an estimate that depends on the instrument used A measurement is read to half of the smallest division or increment. The measuring cylinder measures to the nearest millilitre. If a measurement falls between two divisions it is possible to estimate half a millilitre. This measurement falls between 41 mL and 42 mL The best measurement that can be made with this instrument is: 41.5 mL (±0.5 mL) The last digit is uncertain. Measurement and significant figures A measurement is read to half of the smallest increment. How long is the line? The smallest graduation on the ruler 1 mm. The measurement can be estimated to the nearest 0.5 mm. The line is between 89 mm and 90 mm:  the line is 89.5 mm (length = 89.5 mm ± 0.5 mm) The MEASUREMENT determines the number of significant figures Measurement and significant figures The length is 89.5 mm or 8.95 cm – it has 3 significant figures With this ruler the measurement is between 8 cm and 9 cm. The smallest division is 1 cm ∴ the line can be measured to the nearest 0.5 cm. This measurement is 9.0 cm (±0.5 cm) – it has 2 sig figs The significant figures of the measurement is affected by the type of the ruler. Significant figures What numbers are significant? numbers 1-9 any zero (0) between any two of the numbers 1-9 trailer zeros in a decimal number What numbers are NOT significant? flag zeros spacer zeros ⤫ ⤫⤫ √ √ √ √ eg flag zero 0.005070 kg spacer zeros This number has 4 sig figs trailer zero Practice How many significant figures are there in the following measured values: a) 1.008 b) 0.00340 c) 14.600 d) 0.0001 ANSWERS a) 4 b) 3 c) 5 d) 1 Significant figures How many significant figures in 300 m ? In general: Whole numbers ending in zero or zeroes are ambiguous. Example: This measurement could have 1, 2 or 3 significant figures. Only the person who measured it would know. The ambiguity is removed if scientific notation is used Example: 3  102 m has 1 significant figure 3.0  102 m has 2 significant figures 3.00  102 m has 3 significant figures Calculations with significant figures Multiplying and dividing. When numbers are multiplied or divided the answer should be quoted to smallest number of significant figures – round up or down as needed. Example: 2 sig figs 11.5 m ÷ 3.0 s = 3.8333... ms-1 = 3.8 ms-1 (2 significant figures) 3 sigExample: figs 12.4 gmL-1  11.00 mL = 1364 g = 1360 g (3 sig figs) = 1.36 kg (3 sig figs) Calculations with significant figures Adding and subtracting: When numbers are added or subtracted the answer should be quoted to smallest number of decimal places (dp) Round up or down as needed. Example: 15.89 + 0.0023 + 27.014 = 42.9063 = 42.91 4 dp 3 dp 2 dp Example: 12.4 – 11.02 (2 decimal places ∴ 4 sig figs) = 1.38 = 1.4 (1 decimal places ∴ 2 sig figs) Only round at the end of a calculation to avoid rounding errors Lecture examples 1. How many significant figures do the2. following have: a) 6409 b) 1.23 c) 102003 d) 0.0110 3.104 0.72 1. ANSWERS a) 4 b) 3 c) 6 d) 3 16.2 0.002 20.026 A mixture is prepared using: 3.104 g of A, 0.72 g of B, 16.2 g of D and 0.002 g of E. What is the total mass of the mixture assuming no losses occur? 2. ANSWER total mass = 20.0g Lecture examples 3. Evaluate the expression: 4. Evaluate the expression: 2.00  0.031 273 0.186  298 0.58231000 106.0  23.8 to the correct number of significant figures. 3. 0.31 to the correct number of significant figures. 4. 0.231 The 1000 could have 1, 2, 3 or 4 significant figures. It could also be a conversion factor. If unsure, use common sense. Lecture examples 5. What is the total mass of 6 identical ball bearings, each weighing 5.074 g? ANSWER: 6 × 5.074 = 30.444 g (5 significant figures) In this example “6” is an exact number and is not considered in working out significant figures. It is a short cut way of ADDING UP 5.074g six times Total mass = 5.074 g + 5.074 g 5.074 g 5.074 g 5.074 g 5.074 g = 30.444 g ∴ the number of decimal places remains the same. Lecture examples 6. Convert the following measurements: a) 65.5 mL to L ANSWER 65.5 mL = 65.5  10-3 L = 0.0655 L b) 178 ng to g ANSWER 178 ng = 178 10-9 g = 1.78  10-7 g Unit 3: Elements After completing this block, students should be able to: identify common laboratory equipment understand the importance of safe practice in the laboratory determine the number of significant figures in a measurement apply the rules for significant figures in calculations express any number in correct scientific notation recall the chemical symbols and names of the first 36 elements in the periodic table describe Z, atomic number as a unique identifier of an element distinguish between metallic and non-metallic elements in terms of physical properties locate an element in terms of its group, period and atomic number in the periodic table identify the light metal, non-metal, transition metal, metalloid, actinide and lanthanide zones of the periodic table, (and recall their common properties) identify the members of the alkali metals, alkaline earth, halogen and noble gas families, (and recall their common properties). locate an element in terms of its group, period and atomic number in the periodic table recall the trends of atomic radii and metallic properties across a period differentiate between atoms/molecules/elements/allotropes define allotropes and explain their similarities and differences differentiate between molecular compounds and ionic compounds Elements An element is a pure substance that contains a single type of particle (atom). Our definition: an element is a pure substance incapable of being decomposed by heat and/or by electricity. There are over 100 elements. These are listed in the Periodic Table of the Elements. Atomic number, Z The elements in the Periodic Table are listed in order of their atomic number, Z. The atomic number is a unique identifier of the element. Each element has its own symbol. For example: The atomic number of potassium is 19 The symbol for potassium is K Symbols Learn the symbols for the first 36 elements! You should also know any other commonly encountered element like silver, gold, tin, lead, uranium, the halogens, noble gases, alkali metals and alkaline earth metals) The periodic table of elements – metals and non-metals Metals Semi-metals (metalloids) Non-metals Some physical properties of metals Metals are: lustrous (shiny) most metals are silvery solids at room temperature (25 oC) The exceptions are: mercury which is a silvery liquid gold which is a yellow solid and copper which pinky/orange solid Mercury metal in an ampoule by Wilco Oelen CC-BY-SA-3.0 Gold-crystals CC-BY-SA-3.0-de www.pse-mendelejew.de NatCopper” CC BY-SA 3.0 author Jonathan Zander http://en.wikipedia.org/wiki/Group_11_element#mediaview er/File:NatCopper.jpg Some physical properties of metals Metals are: mechanically flexible, they are malleable and ductile o malleable – can be bent or hammered into thin sheets o ductile – can be drawn into a wire Metals can: – conduct heat – conduct electricity Blacksmith working CC BY-SA 2.0 Jeff Kubina from Columbia, Maryland - Metals, non-metals and semi-metals Non-metals are the elements that don’t exhibit the typical properties of metals. Metals, non-metals and semi-metals Semi-metals (or metalloids) have some properties similar to metals and some of non-metals. - they are often used in semiconductors eg silicon and germanium Elements unique emission spectra Each element has a unique chemical symbol and a unique emission spectrum. The spectrum is like a fingerprint and can be used to identify elements present Source: http://chandra.harvard.edu/graphics/resources/qa/neon.jpg http://chemistry.bd.psu.edu/jircitano/periodic4.html Lecture example The components of a mixture can be identified using an emission spectrum. Which elements are present in final spectrum? The elements in the mixture are strontium, cadmium and sodium Unit 4: Zones of the periodic table After completing this block, students should be able to: identify common laboratory equipment understand the importance of safe practice in the laboratory determine the number of significant figures in a measurement apply the rules for significant figures in calculations express any number in correct scientific notation recall the chemical symbols and names of the first 36 elements in the periodic table describe Z, atomic number as a unique identifier of an element distinguish between metallic and non-metallic elements in terms of physical properties locate an element in terms of its group, period and atomic number in the periodic table identify the light metal, non-metal, transition metal, metalloid, actinide and lanthanide zones of the periodic table, (and recall their common properties) identify the members of the alkali metals, alkaline earth, halogen and noble gas families, (and recall their common properties). locate an element in terms of its group, period and atomic number in the periodic table recall the trends of atomic radii and metallic properties across a period differentiate between atoms/molecules/elements/allotropes define allotropes and explain their similarities and differences differentiate between molecular compounds and ionic compounds The main zones of the periodic table 7 Symbol N LIGHT METALS nitrogen 14.0 Atomic number – locates the position of the element name Standard atomic weight NON-METALS TRANSITION METALS LANTHANIDES ACTINIDES SOFT METALS Classification of the elements ALL METALS Left of zig-zag line (stairs) Shiny, flexible solids (except mercury which is liquid) Good conductors of heat and electricity TRANSITION METALS High density, high melting points (Tm) Compounds are coloured Multiple valencies LIGHT METALS Low density, low melting point (Tm) for a metal very reactive NON-METALS Right of zig-zag line (stairs) Either gaseous or dull brittle solids (except bromine which is liquid) Poor conductors of heat and electricity – insulators (except graphite, C which can conduct electricity) SEMI-METALS some properties of both metals and non-metals The Groups (1—18) and periods (1—7) There are 18 groups in the Periodic table – columns There are 7 periods – rows GROUP 1 – alkali metals GROUP 2 – alkaline earth metals GROUP 17 – halogens GROUP 18 – noble gases period 4 period 5 period 6 period 7 Alkali metals period 3 13 3 4 5 6 7 8 9 10 11 La Ac Lanthanides period 7 Actinides 17 12 Transition metals period 6 14 15 16 http://www.rsc.org/periodic-table 18 Noble gases period 2 Alkaline earth metals 2 period 1 Halogens NOTE: the lanthanides and actinides are moved below for practical reasons 1 The Groups (1—18) and periods (1—7) A periodic table with the lanthanides and actinides in order of atomic number would be very very....... Lanthanides and Actinides don’t belong to a vertical Group Properties of alkali metals – Group 1 Li Na K Rb Cs Fr ALKALI METALS – group 1 silvery metals that are soft and light at RTP* valency +1 very reactive (all react with water to give the hydroxide and H2 gas reactivity increases going down the group all compounds of Group 1 are soluble in water * RTP means room temperature and pressure (25oC and 101.3kPa) Properties of alkaline earth metals – Group 2 ALKALINE EARTH METALS – group 2 Be Mg Ca Sr Ba Ra silvery metals that are soft, light solids at RTP valency +2 reactivity increases going down the group Properties of halogens – Group 17 F Cl Br I At HALOGENS – group 17 non- metals that exist as diatomic molecules at RTP toxic, coloured, irritating odour valency is -1 (although they can have other valencies) reactivity increases going up the group ie fluorine is the most reactive note: very little astatine exists on earth ~ 20 g in total! Ts Element 117 is a new halogen called Tennessine, symbol Ts Properties of noble gases – Group 18 NOBLE GASES – group 18 He Ne Kr Ar Xe Rn non-metallic valency is zero unreactive – exists as atoms odourless and colourless gas with very low boiling points these exist in the atmosphere Og NOTE: Helium and neon form no known compounds but Xe, Kr Ar and Rn can form compounds with oxygen and fluorine. UPDATE!! Element 118 is called Oganesson (symbol, Og) Properties of lanthanides La Ce Pr Nd Pm Sm Eu Gd Tb Dy Hp silvery grey metals valency is +3 but other valencies are possible too Er Tm Yb Lu Properties of actinides MAN-MADE NATURALLY OCCURRING Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm silvery grey metals all actinides are radioactive (mainly alpha decay) Md No Lr Periodic trends - atomic radius ATOMIC RADIUS INCREASES right to left ATOMIC RADIUS INCREASES Each period has the same number of electron shells The atoms on the left have less protons so they are larger the electrons are not attracted as much, so bigger The atoms on the right have more protons the electrons are pulled in closer to the nucleus, so they’re smaller Going down a group increases the number of electron shells so the atomic radius also increases Periodic trends – metallic character METALLIC CHARACTER INCREASES right to left METALLIC CHARACTER INCREASES This is related to how easy it is to remove the valence electron, for larger atoms, the electron is not held as strongly because the number of protons is lower, so this follows the atomic radii trend Tm increases up Group 1 and 2 Carbon has the highest Tm Tungsten is the next highest Tm Tm increases down Group 17 and 18 Periodic trends – melting points, Tm Trends in the periodic table Groups (the columns) in the periodic table are like families of elements: elements in the same group or family will react in a and will form similar compounds. EXAMPLE: What is the formula of sodium silicate? Silicon is in Group 14 like Carbon and so silicate will be like carbonate ∴ sodium silicate is Na2SiO3 similar way Unit 5: Atoms, molecules, elements and allotropes After completing this block, students should be able to: identify common laboratory equipment understand the importance of safe practice in the laboratory determine the number of significant figures in a measurement apply the rules for significant figures in calculations express any number in correct scientific notation recall the chemical symbols and names of the first 36 elements in the periodic table describe Z, atomic number as a unique identifier of an element distinguish between metallic and non-metallic elements in terms of physical properties locate an element in terms of its group, period and atomic number in the periodic table identify the light metal, non-metal, transition metal, metalloid, actinide and lanthanide zones of the periodic table, (and recall their common properties) identify the members of the alkali metals, alkaline earth, halogen and noble gas families, (and recall their common properties). locate an element in terms of its group, period and atomic number in the periodic table recall the trends of atomic radii and metallic properties across a period differentiate between atoms/molecules/elements/allotropes define allotropes and explain their similarities and differences differentiate between molecular compounds and ionic compounds Classification of matter MATTER takes up space and has mass PURE SUBSTANCES distinct properties composition doesn’t change ELEMENTS cannot be decomposed into a simpler substance by heat and/or electricity COMPOUNDS contains two or more elements in a fixed unchanging ratio MIXTURES contains 2 or more pure substances that retain their chemical identity and can be separated by physical means Elements and atoms An element is a pure substance that contains a single type of particle (atom). Our definition: an element is a pure substance incapable of being decomposed by heat and/or by electricity. An atom is the smallest particle of the element There are 118 elements – listed in the Periodic Table of the Elements. Elements At room temperature there are: 11 gaseous elements 2 liquid elements the rest are solid H2, N2, O2, F2, Cl2, He, Ne, Ar, Kr, Xe, Rn Bromine (Br2) and mercury (Hg) Elements At room temperature there are: 11 gaseous elements 2 liquid elements the rest are solid H2, N2, O2, F2, Cl2, He, Ne, Ar, Kr, Xe, Rn Bromine (Br2) and mercury (Hg) Elements can be atomic like the monotomic noble gases: He, Ne, Ar, Kr, Xe, Rn Elements can be molecular like the diatomic gases: H2, N2, O2, F2, Cl2 (and diatomic liquid Br2) Elements can be exist in solid, metallic lattices like the metals at room temperature: Elements can be exist in solid, network lattices like graphite and diamond, allotropes of carbon (and silicon) Allotropes of oxygen, carbon and sulfur What is an allotrope? - forms of an element with different structures and therefore different chemical and physical properties. (Same type of particle – different arrangement in space) Oxygen and ozone - allotropes of oxygen oxygen ozone Source: SI Chemical Data by Aylward and Finlay Graphite, diamond and fullerene – allotropes of carbon Source: SI Chemical Data by Aylward and Finlay Graphite, diamond– allotropes of carbon Monoclinic and orthorhombic sulfur, S8 Sulfur has many (>15) allotropic forms: monoclinic sulfur rhombic sulfur sulfur, S8 Source: SI Chemical Data by Aylward and Finlay Monoclinic and orthorhombic sulfur, S8 sulfur, S8 Unit 6: Molecular and ionic compounds After completing this block, students should be able to: identify common laboratory equipment understand the importance of safe practice in the laboratory determine the number of significant figures in a measurement apply the rules for significant figures in calculations express any number in correct scientific notation recall the chemical symbols and names of the first 36 elements in the periodic table describe Z, atomic number as a unique identifier of an element distinguish between metallic and non-metallic elements in terms of physical properties locate an element in terms of its group, period and atomic number in the periodic table identify the light metal, non-metal, transition metal, metalloid, actinide and lanthanide zones of the periodic table, (and recall their common properties) identify the members of the alkali metals, alkaline earth, halogen and noble gas families, (and recall their common properties). locate an element in terms of its group, period and atomic number in the periodic table recall the trends of atomic radii and metallic properties across a period differentiate between atoms/molecules/elements/allotropes define allotropes and explain their similarities and differences differentiate between molecular compounds and ionic compounds Molecules Molecules are the smallest particle of a substance that has the chemical or physical properties of the substance. Molecules can be elements (same atoms) or compounds (different atoms). Molecules involve non-metal atoms, where there are a fixed number of atoms in each molecule: Oxygen gas has 2 atoms of oxygen bonded together to form an oxygen molecule, O2 it’s an element. Carbon dioxide has 2 atoms of oxygen and 1 atom of carbon bonded together, CO2 it is a compound. Molecular compounds Ionic compounds Ionic compounds form between metals and non-metals (like sodium chloride) At room temperature ionic compounds are usually solid and form ordered crystalline compounds: An ionic crystal is a lattice of alternating positive and negative ions. The number of metal and non-metal atoms in an ionic compound is not fixed but the ratio they combine in is. SODIUM CHLORIDE Further reading and acknowledgements Measurement and Sig Figs http://cyberbridge.mcb.harvard.edu/math_2.html https://physicsworld.com/a/new-definition-of-the-kilogram-comes-into-force/ Image: 7 Fundamental Units, 2019 BIPM Elements Mercury metal in an ampoule by Wilco Oelen CC-BY-SA-3.0 Gold-crystals CC-BY-SA-3.0-de www.pse-mendelejew.de NatCopper” CC BY-SA 3.0 author Jonathan Zander http://en.wikipedia.org/wiki/Group_11_element#mediaviewer/File:NatCopper.jpg Source: http://chandra.harvard.edu/graphics/resources/qa/neon.jpg http://chemistry.bd.psu.edu/jircitano/periodic4.html Further reading and acknowledgements Periodic Table https://www.youtube.com/user/periodicvideos Periodic Table https://www.youtube.com/user/periodicvideos