Chm Notes For 9

CHM Notes for 9/21/09 D= M/V 1.675X10^-31ks/4/3X3.14X(1.0X10^-13=4.0X10^7ks/cm3 D/V 4.0X10^7kg/cm3 4/3X3.14X(.01)^3=17X10^2kg Chaemical Bonds-She sharing or transfer of electrons to obtain stable electron configurations for the bonded atoms. H_1 & O_1 H-O-H=Water molecule. This is the sharing Methane- CH_4 is a covalent compound with bonds composed of two electrons-one from each atom. H | H-C-H | H Shift happen due to magnetism. As you bring the nuclei together you will have a more stable compounds internuclear repulsion IMPERICAL FORMULA Acetylene CH C_2H_2 H-C=C-H Ammonia NH_3

NH_3 H-N-H-H

Red-Oxygen White- Hydrogen Black-Carbon Nitrogen-Light Blue Light Yellow-Fluorine Blue-Phosphorus Yellow-Sulfur Green-Chlorine Nitogen dioxide Sulfer dihydroxide NO_2

H_2S CH_4

H_4N_2CO CH_4ON_2 Originally defined Compounds never put them together. CLASSIFICATION of ELEMENTS & COMPUNDS P, S, SE More than two. Non metals for molecular compounds. Metal+ Non-Metal Ionic Compound K+ I- Potassium is K See table 3.5 Formulas for Ionic Compounds Rules Ionic Compounds contain cations and anions In Formulas sum of cations charges = sum anion charges All formulas for ionic compound are empirical formulas. Write symbols for cation and anion showing charges. Add subscripts to symbols to balance overall charge. Check sum cation charge=anion charge. K+ S2- AL3+ N3ALN Naming a compound Metal Name NaCl= Sodium Chloride FeO Iron(II) Oxide FeO_3 Iron (III) oxide CuO(II)oxide CuO(I) oxide Ag_3N (I) Nitride

Fe(II) Sulfide Rb+ S-2 Rb_2S RuO_2

WEDNESDAY NOTES: Formula Mass (Number of atoms first element in the formula X Atomic mass of first)+ (number of atoms in the second element X atomic mass of 2nd Element) Calculate the formula mass of calcium Nitrate. 1Ca 40.0 2N 28.0 6O 96.0 164amu Mass<-> Moles <-> Number<-> Formula Mass Avagado’s Number C_13 H_18 O_2 Mass to moles 13X12= 156 18X 1= 18 2X 16= 32 200 X 1/10^3=.200 206g/mg .0200g .0200/206 X 6.022X10^23 = 5.838X10^20 3.55x10^22 / 6.022x10^23 X 18g per mol D=m/v

18g/mol X 1ml/g = 1.06ml

Mass Percent Composition= Mass % element X= mass of X per mole/molar mass * 100 CCL_2F_2 Calc C_2 H_4 O_2

O= 32.0/60.0 * 100 = 53.3 % Mass Compound mol compound  mol element  mass element  What mass (in grams) of Iron(III) oxide contains 58.7 grams of iron Fe ^3+ O^2Fe_2 O_3 159.7 s/mol 58.7gFe/55.85 g/mol = 1.051mol Fe* ½ mole Fe_2O_3 0.5255 *159.7= 83.9g Someone consumes 22g of sodium chloride per day 22g NaCl/58.5 g/mol= 0.376= 1/1 mol * mass of sodium 23.0= 8.7g 7.2g Al_2(SO)_4_3 27.0 32.0 16.0 7.2g/342 * 12.0/1Al(SO_4)_3 * 16/ 1mol 7.25ml * 0.602 s/ml * 1/58.0 * 4/1 * 12.0g/m= 3.61g This equals Volume Emperical Formula 1. Determine the moles of each element in the compound 2. divide each moles by value of minimum moles. 3. if the resulting numbers are not whole numbers, * all by a small whole number to get whole numbers and use these as subscripts for empirical formula. n/min n 2.88/1= 28 3.9/1= 1.35 C 165g 165/12=13.76 =1 H27.8 27.8/1= 27.8 =2 O220.2 220.2/16= 13.76 =1

C= 75.69% =6.31 H=8.80%

=8.8

O=15.51%

=.96

75.69 85.62% C 14.38%H a. Obtain the empirical formula. Propane burning in oxygen. C_3 H_8 + 5O_2 3CO_2 + 4H_2O

Ethanol (CH_3CH_2OH) burns in oxygen to form water and carbon Dioxide. Solutions of lead (II) nitrate, Pb(NO_3)_2, and sodium Chloride, NaCl, are mixed precipitating PbCl_2.