Chem Final Review

Pure Substances and Mixtures What is the difference between a pure substance and a mixture? What are the two types of mixtures? Which type of mixture are these? Pure substance is made of one substance and a mixture is a combination of two of more substances Heterogeneous- made of two different phases of matter Homogeneous- made of one phase of matter; solution Homogeneous Heterogeneous

The ATOM Element Symbol Element Name Mass Number # of p+ # of n0 # of e- Cl-35 Mn-55 K-42 Si-26 Element Symbol Element Name Mass Number # of p+ # of n0 # of e- Cl-35 Chlorine 35 17 18 Mn-55 Manganese 55 25 30 K-42 Potassium 42 19 23 Si-26 Silicon 26 14 12

Calculating Atomic Mass Calculate the atomic mass: Atomic mass= (23.985)(0.7870) (24.986)(0.1013) +(25.983)(0.1117) 24.31 amu

Significant Figures (sig-figs) The number of digits reported in a measurement reflect the accuracy of the measurement and the precision of the measuring device. Report the fewest significant figures Fewest number for multiplication and division Fewest decimal places for addition and subtraction

Significant Figures (sig-figs) Non-zero numbers (e.g. 1, 2, 3…9) are significant. Zeros between non-zero numbers are always significant. (e.g. 204 ml) (the sandwich rule) Zeros before the first non-zero digit are not significant. (e.g. 0.0003 has one.) Zeros at the end of the number after a decimal place are significant. (e.g. 123.00 g) Zeros at the end of a number before a decimal place are ambiguous (e.g. 10,300 g).

Periodic Table Groups A: Alkali metals E: Nobel Gases Name special names for these sections of the table: E A B D C F A: Alkali metals E: Nobel Gases B: Alkaline Earth metals F: Inner Transition metals C: Transition metals D: Halogens

Metals, Non-metals, and Metalloids What are the properties of metals? What are the properties of non-metals? What is a semiconductor? Malleable, Ductile, Lustrous, Good Conductors Dull, Brittle, and Insulators Metalloid material that can conduct electricity

Periodic Table Trends F-, O2-, N3-, Cl-, Br- F, Br, B, Li, Rb Put these elements in order of decreasing Atomic radius: Al, Ag, Au, Ba, Sr Put these ions in order of increasing Ionic Size: Br-, O2-, N3-, Cl-, F- Put these elements in order of decreasing electronegativity: Br, Rb, B, Li, F Ba, Sr, Au, Ag, Al F-, O2-, N3-, Cl-, Br- F, Br, B, Li, Rb

Types of Chemical Reactions What are the 5 types of chemical reactions? Synthesis Double Replacement Decomposition Single Replacement Combustion H2 + O2 ® H2O ® Zn + H2SO4 ® HgO ® KBr +Cl2 ® AgNO3 + NaCl ® Mg(OH)2 + H2SO3 ® Synthesis Decomposition Single Replacement Double Replacement

Dynamic Equilibrium HI(g) will decrease in concentration Look at the following reaction at equilibrium: H2(g) + I2(g) <===> 2HI (g) What will adding H2(g) do the concentration of HI(g)? What will removing I2(g) do to the concentration of HI(g)? HI(g) will increase in concentration HI(g) will decrease in concentration

Radioactive Decay Alpha, Beta, and Gamma decay Beta decay What are the 3 types of radioactive decay? Which is most dangerous to living things? What type of radioactive decay is this? What is missing from this equation? Alpha, Beta, and Gamma decay Beta decay

Calculating Half-Life 131I has a half-life of 8.04 days. Assuming you start with a 1.53 mg sample of 131I, how many mg will remain after 13.0 days __________ ? Nt = N0 x 0.5(y) Nt= 1.53mg x 0.5(13.0/8.04) Nt= 0.499

Lewis Dot Structures Draw the Lewis Dot structure for the following: Al, Cl, B, O, NaCl, O2

Compound Naming Magnesium oxide Aluminum sulfide Dinitrogen Pentoxide Name for following compounds: MgO AlS3 N2O5 Na3PO4 Mg(OH)2 (NH4)2 Cr2O7 K2SO3 CrPO4 Fe2 (SiO3)3 Hg(C2H3O2)2 Magnesium oxide Aluminum sulfide Dinitrogen Pentoxide Sodium phosphate Magnesium hydroxide Ammonium dichromate Potassium sulfite Chromium (III) phosphate Iron (III) silicate Mercury (II) acetate

Compound Naming II Au(CN)3 Ca(HCO3)2 Sr(NO3)2 H2CO3 CaCl2 ∙ 7H2O H2SO3 Write the formula for following compounds: Gold (III) cyanide Calcium hydrogen carbonate Strontium nitrate Carbonic acid Calcium chloride septahydrate Sulfurous acid Lead (IV) phosphite Lithium chlorite Magnesium hypochlorite Beryllium perchlorate Au(CN)3 Ca(HCO3)2 Sr(NO3)2 H2CO3 CaCl2 ∙ 7H2O H2SO3 Pb3(PO3)4 LiClO2 Mg(ClO)2 Be(ClO4)2

Electron Configurations What are the principle quantum energy levels and sublevels? How many orbitals in each sublevel? Write the full electron configuration for Iodine: Write the abbreviate electron configuration for Ra+2: n= 1, 2, 3, 4, 5, 6, 7 s= 1 orbitals p= 3 orbitals d= 5 orbitals f= 7 orbitals 1s2 2s22p6 3s23p6 4s23d104p6 5s24d105p5 [Rn]

Molecular Structures 2, 0; Linear; 180 3, 1; Trigonal pyramidal; 107 Name the molecular structure for the following and list the number of lone pairs and bonds: CO2 NH3 SeF6 CH4 H2O SO2 PCl5 SO3 PCl3 2, 0; Linear; 180 3, 1; Trigonal pyramidal; 107 6, 0; Octahedral; 90 4, 0; Tetrahedral; 109.5 2, 2; Bent; 105 2, 1; Bent; 120 5, 0; Trigonal bypyrmidal; 90, 120 3, 0; Trigonal planar; 120

Stoichiometry = 1.81 mol N2O4 Mol K= 0.89 g/39 g = 0.02 mol K Determine the number of moles of N2O4 needed to react completely with 3.62 mol of N2H4for the reaction 2 N2H4(l) + N2O4 (l) → 3 N2(g) + 4 H2O(l) A sample of a substance is determined to be composed of 0.89 grams of potassium, 1.18 grams of chromium, and 1.27 grams of oxygen. Calculate the empirical formula of this substance.  3.62 mol N2H4 1 mol N2O4 = 1.81 mol N2O4 2 mol N2H4 K= 0.02 mol K/ 0.02 mol Cr = 1; K Cr= 0.02 mol Cr/ 0.02 mol Cr = 1; Cr O= 0.08 mol O/ 0.02 mol Cr = 4; O4 Mol K= 0.89 g/39 g = 0.02 mol K Mol Cr= 1.18 g/ 52 g = 0.02 mol Cr Mol O= 1.27 g/ 16 g = 0.08 mol O KCrO4; Potassium chromate

Stoichiometry C2NOH3 = 57 g 171.2 g / 57 g = 3 (C2NOH3) x 3 = C6N3O3H6 How many atoms are in 90 L of O2 gas at STP?  What is the empirical formula of the compound that is 42.10 % carbon, 5.26 % hydrogen, 24.56 % nitrogen, and 28.07 % oxygen? If molecular mass of the compound is found to be 171.2 g/mol what is it's molecular formula?  90 L O2 1 mol O2 6.022 x 1023 atoms of O2 = 2.4 x 1024 atoms of O2 22.4 L O2 1 mol O2 C2NOH3 = 57 g 171.2 g / 57 g = 3 (C2NOH3) x 3 = C6N3O3H6