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The nature of matter Chemistry. Substance, Element, Mixture Take a sample of an unknown material. Divide it into smaller and smaller pieces. Are the properties.

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Presentation on theme: "The nature of matter Chemistry. Substance, Element, Mixture Take a sample of an unknown material. Divide it into smaller and smaller pieces. Are the properties."— Presentation transcript:

1 The nature of matter Chemistry

2 Substance, Element, Mixture Take a sample of an unknown material. Divide it into smaller and smaller pieces. Are the properties remaining the same? Apply the process to the following: ◦Milk ◦Water ◦Anti-freeze ◦Lead pipe ◦14k gold ◦Sugar Water, sugar, protein, fat H2O Propylene (or ethylene)glycol, water Pb, industrially purified Gold, silver alloy Sucrose

3 Properties of Matter Any characteristic that can be used to describe or identify matter is a property. Intensive properties have values that do not depend upon the amount of matter. Extensive properties have values that depend on the sample size.

4 Physical & Chemical Properties Physical properties are characteristics that do not involve a change in the chemical makeup of the sample. ◦A change in phase Chemical properties are characteristics that do involve a change in chemical makeup. ◦Paper burns

5 Physical Properties Physical properties are characteristics that do not involve a change in the chemical makeup of the sample. ◦A change in phase

6 Chemical properties Chemical properties are characteristics that do involve a change in chemical makeup. ◦Paper burns Yellow vanadium (VI) is swirled with Jones Reductor and will progressively change color until it reaches the violet vanadium (II). Alternatively, violet vanadium(II) is oxidized through a series of colors by permanganate to a final yellow color.

7 Density Density is the ratio of mass (the amount of matter present) to volume (the amount of space that the matter occupies). The ratio of mass to volume of a substance remains a constant for a given set of circumstances. Standard measures of density are reported at 1 atmosphere of pressure and a temperature of 25 degrees Celsius.

8 Density Density is the ratio of mass (the amount of matter present) to volume (the amount of space that the matter occupies). The ratio of mass to volume of a substance remains a constant for a given set of circumstances. Standard measures of density are reported at 1 atmosphere of pressure and a temperature of 25 degrees Celsius.

9 Example experiment

10 Early known elements Earliest recorded history includes information about ten elements (Sb, C, Cu, Au, Fe, Pb, Hg, Ag, S, Sn). These elements occur naturally in native (+0) state. Photos by Paul Silverman Cu S Pb

11 Antiquity to 1800 Gray 1800-1849 Green 1900-1949 Dark Purple 1950-1999 Light Purple 2000- 2012 not shown 112 is named Copernicium 114 is named Flerovium 116 is Livermorium (Lawrence Livermore Laboratories) AntiquityAntiquity to Middle Ages (14 elements): unrecorded discoveries up into the Middle Ages (Cu, Cr, Fe, Cu, Zn, Ag, Au, C, S, As, Sn, Sb, Pb, Bi)Middle Ages Middle Ages – 1800 (22 elements): discoveries during the age of enlightenment (H, Be, Mg, Sr, Ba, Y, Ti, Zr, Mo, Co, Ni, Pt, O, N, W, Mn, Cl, Te, P, U, Al, B)age of enlightenment (H, Be, Mg, Sr, Ba, Y, Ti, Zr, Mo, Co, Ni, Pt, O, N, W, Mn, Cl, Te, P, U, Al, B) 1800–1849 (22 elements): scientific and industrial revolutions (Li, Na, K, Ca, V, Nb, Ta, Ru, Rh, Pd, Cd, Os, Ir, Si, Se, Br, I, La, Ce, Nd, Tb, Er, Th)industrial 1850–1899 (26 elements): the age of classifying elements; application of spectrum analysis techniques: Boisbaudran, Bunsen, Crookes, Kirchhoff, and others "hunting emission line signatures" (Rb, Cs, Sc, Ra, Tc, Re, Ga, Ge, In, Tl, Po, He, Ne, Ar, Kr, Xe, Pr, Ac, Sm, Eu, Gd, Dy, Ho, Tm, Yb)classifying elementsspectrum analysis BoisbaudranBunsenCrookesKirchhoffemission line 1900–1949 (13 elements): development of old quantum theory and quantum mechanics (Fr, Hf, Tc, At, Rn, Pm, Pa, Np, Pu, Am, Cm. Bk, Lu)old quantum theoryquantum mechanics 1950–1999 (16 elements): post Manhattan project; synthesis of atomic numbers 98 and above (colliders, bombardment techniques)(Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, Bk, Cf, Es, Fm, Md, No, Lr)Manhattan projectsynthesiscolliders Since 2000 (5 elements): recent synthesis

12 Organization of Elements The first work to inventory the elements was published in 1789 by French scientist Antoine Lavoisier. A surge in discovery of new elements occurred through 1850’s. The work of John Dalton, 1805, found that elements have a consistent property of atomic mass. He worked to develop the ancient idea of atoms. Observation of reactions and properties of different elements led Johann Dobereiner’s hypothesis of triads of related elements in 1829. Cl, Br, and I; or Ca, Sr, and Ba. 16 triads were described by 1843.

13 First Periodic Table First organizational chart was published by Dmitri Mendeleev in 1869. It had seven horizontal rows (periods) and 18 vertical columns (groups). The primary basis for his organization was the atomic mass. Elements in a group have similar chemical properties. There are 90 naturally occurring elements. The other elements have been artificially produced by nuclear chemists in high-energy particle accelerators.

14 Mendeleev’s Table Medeleev left blanks in his table where he predicted there were elements missing based on the patterns he observed in known elements.

15 Elements missing from Mendeleev’s Table Other scientists were able to use Medeleev’s predictions to look for and find Scandium, Gallium, and Germanium.

16 IUPAC Periodic Table The periodic table has a total of 32 groups rather than the 18 groups. To fit the chart on a page, the 14 groups that follow lanthanum or actinide are pulled out and displayed below the main chart.

17 Group 1A: Alkali metals Lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs) are shiny soft metals. All react rapidly (often violently) with water to form highly alkaline (basic) products. Due to the high reactivity, the alkali metals are never found in nature in the pure state, only in combinations with other elements.

18 Group 2A: Alkaline earth metals Beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra) are also lustrous, silvery metals. These metals are less reactive than Group I metals and produce alkaline products. Alkaline earth elements are also never found in nature in their pure state.

19 Group 7A: Halogens Fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) are colorful, corrosive nonmetals. Halogens are found in nature only in combination with other elements, example: table salt (NaCl). Hals means salt in Greek. Astatine is a halogen, but it occurs in tiny amounts with little known about it.

20 Group 8A: Noble gases Helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn) are gases of very low reactivity. He, Ne, and Ar do not combine with any other elements. Kr and Xe combine with very few elements.

21 Metals Metals are the largest category of elements. These are found on the left side of the table. All (except mercury, Hg) are solids at room temperature. Most have silvery shine commonly associated with metals. Most are malleable, not brittle. Metals are good conductors of heat and electricity.

22 Nonmetals Nonmetals (17 in all) are located on the right side of the table. Their appearance can be characterized by lack of silvery lustre. Only five are solids at room temperature, and they are brittle (carbon, phosphorus, sulfur, selenium, and iodine). Bromine is a liquid. All others are gases. Some are brightly colored such as sulfur yellow. All are poor conductors of heat & electricity.

23 Semimetals Semimetals occur diagonally from boron (B) to astatine (As) at the base of group 7A. Included are silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te). Semimetals have intermediate properties. Silvery in appearance, solid at room temperature, brittle, and poor conductors of heat and electricity.

24 Measurement Scientific experimentation is performed in a way that can be replicated by others. It is necessary to use common units and nomenclature. International System of Units (SI for the French: Systeme Internationale d’Unites) was established by agreement in 1960. Metric system has seven fundamental units Physical QuantityName of UnitAbbreviation masskilogramkg lengthmeterm temperatureKelvinK amount of substancemolemol timeseconds electric currentampereamp luminous intensitycandelacd

25 Prefixes for Multiples of SI Units Factor PrefixSymbol 1,000,000,0001.00E+09gigaG 1,000,0001.00E+06megaM 1,0001.00E+03kilok 1001.00E+02hectoh 101.00E+01dekada 0.11.00E-01decida 0.011.00E-02centic 0.0011.00E-03milli m 0.0000011.00E-06micro  0.0000000011.00E-09nano n 0.0000000000011.00E-12picop The size of an atom of silicon and the diameter of a star are both measured in meters. SI units are modified by the use of prefixes to bring the unit into scale for the description of scientific observations.

26 Scientific notation For very large or very small numbers, use scientific notation. The exponential format is A x 10 n A is between 1 and 10. The exponent, n, is either a positive or negative integer. Examples: 83,450 = 8.345 x 10 4 (A x 10 n )(B x 10 m ) = AB x 10 m + n (A x 10 n ) m = A m x 10 m x n

27 Mass Mass is the amount of matter. Matter a generic term of anything with a physical presence. SI unit is kilogram (kg = 2.205US lb). Common prefixes: gram = 10 -3 kg milligram = 10 -6 kg microgram = 10 -9 kg

28 Length SI unit for length is the meter (m = 39.37 in). Common prefixes: centimeter = 10 -2 m millimeter = 10 -3 m micrometer = 10 -6 m nanometer = 10 -9 m Na atom is 375pm picometer = 10 -12 m

29 Temperature SI unit for temperature is the Kelvin (omit the word degree) The size of the unit is equal to the degree Celsius ( o C). The unit is equal to one hundredth of the interval between the freezing point of water and the boiling point of water at STP. 0 o C freezing point/ 100 o C boiling point 0 K coldest possible temperature or absolute zero (-273.15 co )

30 Prepare for experiments Measure 100mL of water to use in an experiment to produce reliable results. ◦Equipment: Erlenmeyer flask Scale Volumetric flask Beaker Cooking measure Hypothesis: (Frances)If the volumetric flask is used then the results will both more precise and more accurate.

31 Analysis and conclusions Results: Conclusion: Write your conclusion based on the data collected, statistical analysis, and the fact that 100 ml of water will have a mass of 100gm at STP. Weight of 100 ml of Water Total weight Measuring deviceTare WeightTrial 1Trial 2Trial 3 Average weight Net weight Beaker217.68311.27311.85314.17312.4394.75 Volumetric Flask57.22156.93156.82156.88156.876666799.65667 Erhlenmeyer Flask206.93287.62297.38300.69295.2388.3 Measuring Cup418.01519.74519.54518.41519.23101.22


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