2015-2016 HONORS Chemistry Midterm Review This review sheet is a list of topics and sample practice problems only. The practice problems are good representation of what to expect on the midterm, but it is not enough to just study from the review. You need to look over your notes, old review sheets, tests and quizzes, homework, etc. Ask questions!!!! You may check your answers online and I am available Tuesday, Wednesday, and Thursdays for extra help. Chapter 1 & 2: Intro to Chemistry What is chemistry Uncertainty in Measurement sig figs Physical and chemical properties Physical and chemical changes 1. Determine the number of significant figures in the following values: a. 6.70 3 c. 15,300 3 b. 0.03260 4 d. 4.68 3 2. Perform the following calculations and express your answer with the correct number of significant figures: a. 34.0 x 45.62 = 1550 b. 45 95.24 = -50. Chapter 3: Atomic Structure Models of the atom (Modern atomic theory) Isotopic Notation, Subatomic particles Atomic Orbitals s, p, d shapes Electron configurations Valence electrons Periodic Law 3. Describe the basic structure of the atom in the modern atomic theory (be able to label protons, neutrons, electrons, and the nucleus) (Ch. 3): Protons, neutrons in nucleus (densely packed) Electrons surrounding nucleus in orbitals/clouds Protons: + Electrons: - Neutrons: neutral
14 C 4. 6 protons = 6 neutrons = 8 electrons = 6 5. Sketch s and p orbitals (Ch 3): Electron clouds where there is a probability of finding electrons 6. Write the electron configuration for Bromine. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5 7. What element has the following electron configuration: 1s 2 2s 2 2p 6 3s 3 3p 6 4s 2 3d 5 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 5 Manganese Chapter 4: The Periodic Table Organization of the Periodic Table (Periodic Law) Periodic Trends: Electronegativity Recognize properties of main groups 8. How are elements organized on the periodic table? Describe common trends across the periods and down the groups. (Ch 4): Elements are grouped on periodic table by their physical and chemical properties (atomic number increases). The physical and chemical properties of the elements are periodic functions of their atomic numbers (pg 116). 9. Label the following areas on your periodic table (some may overlap) (Ch 4):
Chapter 5 & 6: Chemical Bonding Octet Rule Naming and writing formulas Properties of ionic versus covalent compounds Lewis Dot structures Polar vs. Non-polar VSEPR 10. Compare and contrast ionic and covalent bonds (Ch 5 and 6, essay): Ionic Both Covalent Metal & nonmetal Giving/taking electrons (transferring) High MP and BP Conducts electricity when molten or dissolved in water Both form stable octets (8 valence electrons) Both do not conduct electricity as solids Nonmetal & nonmetal Sharing of electrons Low MP and BP Poor conductors of electricity 11. Name the following ionic compounds or covalent molecules (Ch 5, 6): NH4Cl Ammonium chloride CO2 Carbon dioxide SiF4 Silicon tetrafluoride CuO Copper(II) oxide NaF Sodium fluoride CCl4 Carbon tetrachloride Mg(NO3)2 Magnesium nitrate SnO4 Tin (IV) oxide 12. Write formulas for the following ionic compounds of covalent molecules (Ch 5, 6): a. magnesium hydroxide Mg(OH)2 b. carbon monoxide CO c. copper(ii) chloride CuCl2 d. selenium hexachloride SeCl6 e. calcium hydroxide Ca(OH)2 f. sodium phosphate Na3PO4 g. dinitrogen pentoxide N2O5 h. phosphorus trichloride PCl3
11. Draw Lewis Structures (Ch 6): CH3Cl OF2 SO3 12. Identify the shape and bond angle of molecular compounds (Ch 6): Lewis Structure Shape Bond angles NH3 Trigonal Pyramidal <109.5 SO2 Bent <120 CCl4 Tetrahedral 109.5
Chapter 8: The Mole Topics: Mole Avogadro s number Percent composition Empirical formulas Molecular formulas Be able to Calculate molar mass Convert between grams and moles Convert between number of particles and moles Perform multi-step conversions Calculate percent composition Determine empirical formula Determine molecular formula 13. Determine the molar mass of the following compounds (Ch 8): Al2(SO4)3 2(26.98) + 3(32.06) + 12(16.00) = 342.14 KBr Li2O 39.10 + 79.90 = 119.00g/mol 2(6.94) + 16.00 = 29.88g/mol 14. Find the percent composition of each element (Ch 8): %Mg in MgSO4? Total mass MgSO4: 24.31 + 32.06 + 4(16.00) = 120.37 g/mol Mg: 24.31/120.37 x 100% = 20.20% Mg S: 32.06/120.37 x 100% = 26.63% S O: 64.00/120.37 x 100% = 53.17% O %H in C2H5O? Total mass C2H5O: 2(12.01) + 5(1.01) + 16.00 = 45.07 g/mol C: 24.02/45.07x 100% = 53.29% C H: 5.05/45.07x 100% = 1.11% H O: 64.00/45.07x 100% = 35.50% O
15. Mole conversions (Ch 8): # of moles in 2.5g of Aluminum Oxide? 2.5 g x 1 mol =.025mol 101.96g # of moles in 15g of Neon? 15 g x 1 mol =.74mol 20.18g # of atoms in 0.5mol of Gold?.5 mol x 6.02 x 10 23 atoms = 3 x 10 23 atoms 1mol # of atoms in 1.5 grams of Zinc (II) Chloride? 1.5g x 1 mol x 6.02 x 10 23 atoms = 6.6 x 10 22 atoms 136.29g 1mol