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Final Review 1 Name ______KEY __________________________ Test Date ______________ Period ______ CP Chemistry – Final Exam Review Show your work and round using significant figure rules for all the problems. 1. What is chemistry? Chemistry is the study of matter and the changes it undergoes. 2. 3. 4. 5. Write the following in scientific notation: a. .005 5 x 10-3 c. 53099000 5.3099 x 107 b. 5050 5.05 x 103 d. 0.00053030 5.3030 x 10-4 Write the following in standard notation: a. 1.5x103 1500 c. 4x10-5 0.00004 b. 3.75 x10-2 0.0375 d. 9.12 x107 91200000 How many significant figures are in the following: a. 0.02 1 c. 501 3 b. 501.0 4 d. 0.020 2 Calculate and report in correct significant figures: a. 52.568 cm + 689.45 cm + 55.5694 cm = 797.59 cm b. 8426. 200 g ÷ 254 mol = 6. You measure a Calcium cube to have 2.01 cm sides and a mass of 11.6 grams: a. What is the density as you calculate it? v = s3 = (2.01 cm)3 = 8.12 cm3 d= 7. 33.2 g /mol m 11.6 g = = 1.43 g/cm3 v 8.12 cm3 b. If calcium’s accepted density is 1.54 g/cm3, what is your percent error? |1.54 g/cm3 – 1.43 g/cm3| %error = x 100 = 7.14 % 1.54 g/cm3 Perform the following conversions: a. 53.1 mm to m 1m 53.1 mm x 3 = 0.0531 m 10 mm b. 18.4 kg to dag 1 x 10-1 dag 18.4 kg x = 1840 dag 1 x 10-3 kg c. 93.6 mi to km (1 mi = 1.6 km) 1.6 km 93.6 mi x = 150. km 1 mi Final Review 2 8. 9. 10. 11. What is the difference between precision and accuracy? Precision is the reproducibility of data, while accuracy is how close the measurement is to a known value. What two properties does all matter have? All matter has mass and volume. What is the difference between an element, compound, and mixture? An element is the simplest form of matter, and one type of atom. A compound is two or more atoms chemically combined. A mixture is two or more substances physically combined. Identify the following as either a(n) element, compound, homogeneous mixture, or heterogeneous mixture: a. Chlorine Element d. Steel Homogeneous Mixture b. Water c. Soil 12. 13. 14. 15. Compound e. NaCl Compound Heterogeneous Mixture f. Paint Heterogeneous Mixture Classify the following as a chemical or a physical property. a. Color Physical b. Reaction with HCl Chemical c. Boiling point Physical d. Density Physical e. Hardness Physical f. Flammablity Chemical Compare and contrast chemical and physical changes. List signs of chemical changes. A chemical change results in a new, different substance, while a physical change does not. Chemical changes are shown with bubbling, color change, precipitate formation, temperature change and a substance “disappearing.” What is the law of conservation of mass? Give an example to explain it. The law of conservation of mass states that matter is neither created nor destroyed in a chemical reaction. If liquid water is broken into H2 and O2 gases, the sum of the gases’ mass equals the water’s mass. What did each of these scientists contribute to chemistry: a. Dalton c. Mendeleev Dalton’s Atomic Theory. Modern periodic table. Partial Pressure. Law of Predicted properties of Multiple Proportions. undiscovered elements. b. Rutherford d. Thompson Discovered the nucleus of Discovered electron in the the atom. Nuclear Atomic cathode ray tube Model. experiment. Plum Pudding Model. Final Review 3 16. What happens to an atom when it becomes an anion? A cation? 17. What is different about 2 isotopes of titanium? What is the same? 18. Hydrogen-1 b. 45 c. 183 d. 20. Isotopes of titanium have same number of protons and atomic number. Different isotopes have different amounts of neutrons and mass numbers. Complete the following table (assume atoms are neutral): Atomic Mass Number of Isotope Name number Number Protons a. 19. An anion is the result of gaining an electron to become negatively charged. A cation loses an electron to be positively charged. Sc W Bromine - 81 Number of Neutrons Number of Electrons 1 1 1 0 1 21 45 21 24 21 74 183 74 109 74 35 81 35 46 35 Element X has two naturally occurring isotopes. Isotope 35X has an abundance of 77.60% and isotope 37X has an abundance of 22.40 %. a. What is the atomic mass of element X (to 2 decimal places)? 35 X: 35 amu x 0.7760 = 27.16 amu mass of X = 35.45 amu 37 X: 37 amu x 0.2240 = 8.29 amu b. What is the identity of element X? Element X is Chlorine (Cl) What is the makeup and symbol for an:` a. Alpha particle? An alpha particle (α) is a helium nucleus ( 42He , 2 protons, 2 electrons). b. Beta particle? A beta particle (β) is an electron ( -10e). c. Gamma particle? 21. Write a balanced equation for Cobalt-60 emitting an alpha particle. 60 27 22. 4 Co→ 56 25 Mn+ 2 He Write a balanced equation for Uranium-236 emitting a beta particle. 236 92 23. A gamma particle (γ) is high-energy radiation. U→ 236 Np+ -10 e 93 What is electromagnetic radiation? What is the speed of all electromagnetic radiation? Electromagnetic radiation is energy that travels like a wave through space. All radiation moves at the speed of light (3 x 108 m/s). Final Review 4 24. What frequency of light will have a wavelength of 3.12 x 10-2 m? v= 25. c 3 x 108 m/s = = 9.6 x 109 Hz λ 3.12 x 10-2 m What is the energy of a wave with a frequency of 1.76 x 1016 Hz? E = hv = (6.626 x 10-34 J·s)(1.76 x 1016 Hz) = 1.16 x 10-17 J Explain in detail how an atom emits light and why it is a different color for each element. What do quantum numbers tell you about an electron? 30. a. Al 1s2 2s2 2p6 b. N 1s2 2s2 2p3 c. K 1s2 2s2 2p6 3s2 3p1 3s2 3p6 Write the noble gas shorthand for the following: a. Mg [Ne] 3s2 c. Ta [Xe] 6s2 4f14 5d3 b. Fe [Ar] 4s2 3d6 d. Br [Ar] 4s2 3d10 4p5 Determine the number of valence electrons and draw the Lewis dot diagram for: a. P – 5 valence ec. Ca – 2 valence e- ∙ ∙ ∙∙ P ∙ b. O – 6 valence e∙∙ ∙ ∙ O 31. ∙∙ Ca d. I – 7 valence e- ∙∙ I ∙∙ When nitrogen becomes an ion, its electron configuration is the same as what element? 32. 4s1 ∙ 29. What is the COMPLETE electron configuration with orbital diagram for the following: ∙∙ 28. Quantum numbers tell you the most likely location of an electron in an atom. ∙ 27. An excited atom moves up to a higher energy level. On the way down, it releases the extra energy as light. Each element has its own electron configuration and its own color released from the electrons. ∙ 26. Nitrogen gains 3 electrons to be like Neon. Use the periodic table to name the following: a. Group 1 Alkali Metals b. Group 2 Alkaline Earth Metals c. Group 7 Halogens d. Group 8 Noble Gases Final Review 5 33. What is the periodic law? 34. 35. The periodic law states that properties repeat periodically when elements are listed in order of increasing atomic number. Write the symbol (with charge) for the most common ions formed by: a. Boron B3+ c. Nitrogen N3- b. Hydrogen H+ d. Oxygen O2- Which has the smaller atomic radius? a. Hg 36. Bi b. F or O or Ga b. Al or Tl Metals are shiny, ductile, generally solid (except Hg), and cations. Nonmetals are brittle, not ductile, usually liquid or gas and anions. Ionic bonds donate electrons between metals and nonmetals. Covalent bonds share electrons between 2 nonmetals. Metallic bonds have metal cations in a sea of electrons. A single bond shares 2 e-, double shares 4 e- and triple shares 6 e-. Compare ionic and molecular compounds in terms of melting point and conductivity. 42. or How many electrons are shared in a single covalent bond? A double bond? A triple bond? 41. Se Compare and contrast ionic bonds and covalent bonds. 40. or What are the properties of a metal? A nonmetal? 39. b. Ca Which has the higher electronegativity? a. Br 38. Cd Which has the higher ionization energy? a. N 37. or Ionic compounds have a higher melting point and conductivity than molecular compounds. What type(s) of bonds are in the following: a. Ca3P2 b. Sn(OH)2 c. H2O d. BaSO4 Ionic Ionic and Covalent Covalent Ionic and Covalent e. CsF Ionic f. P2O5 Covalent g. CdO Ionic h. AgNO3 Ionic and Covalent Final Review 6 43. Write the name or formula for the following: a. Sulfur Difluoride SF2 b. Pb(C2H3O2)2 Lead (II) Acetate c. Potassium Iodide KI d. CO2 Carbon Dioxide e. Fe2O3 Iron (III) Oxide f. Cobalt (II) Carbonate CoCO3 g. Tetraphosphorus Pentoxide P4O5 h. BaBr2 44. What is the basis of the VSEPR theory? 45. Formula Barium Bromide The VSEPR theory is based on electron pairs in atoms repelling each other as much as possible. Complete the following table: Lewis Structure Molecular Shape Molecule Polarity Strongest Intermolecular Force a H2O Bent Polar Hydrogen Bonds b PCl3 Trigonal Pyramidal Polar Dipole-Dipole Forces c CF4 Tetrahedral Nonpolar London Dispersion Forces Final Review 7 46. Name the seven diatomic elements. Bromine (Br2), Iodine (I2), Nitrogen (N2), Chlorine (Cl2), Hydrogen (H2), Oxygen (O2), and Fluorine (F2). 47. An exothermic reaction releases energy as a product. 48. An endothermic reaction takes in energy as a reactant. 49. Write the general formula and explain what occurs in the reaction types below: A + B AB a. Synthesis 2 substances combine to make 1 compound. AB A+B b. Decomposition 1 compound breaks down into 2 or more simpler substances. A + BX AX + B or c. Single Replacement A free metal replaces another metal in a compound or a halogen replaces a halogen in a compound. AX + BY AY + BX d. Double Replacement 2 compounds switch anions. CxHy + O2 CO2 + H2O e. Combustion 50. A substance (usually a hydrocarbon) burns in oxygen to make carbon dioxide and water. Balance and classify the following equations: a. 4 Fe + 3 O2 2 Fe2O3 Synthesis b. 2 Al(NO3)3 + 3 H2SO4 c. 2 PbO2 51. Y + AX AY + X 2 PbO + Al2(SO4)3 + 6 HNO3 O2 Double Replacement Decomposition d. 2 KBr + Cl2 2 KCl + Br2 Single Replacement e. CH4 + 2 O2 CO2 + 2 H2O Combustion For the reactions below, predict the products, balance, and classify the type: a. HCl + NaOH NaCl + H2O b. 2 Al + 3 Cl2 2 AlCl3 Synthesis c. 2 H2O 2 H2 + O2 d. 2 C2H6 + 7 O2 4 CO2 + Double Replacement Decomposition 6 H2O Combustion Final Review 8 52. 53. 54. 55. 56. 57. What do these reaction symbols represent? a. (g) Gas d. Reversible Reaction e. (aq) Aqueous Solution b. Yields or Reacts to Form f. (s) Solid c. (l) Liquid What is the molar mass of CO2? C: 1 x 12.01 g/mol = 12.01 g/mol, O: 2 x 16.00 g/mol = 32.00 g/mol MM=44.01 g/mole What is the mass in grams of 8.44 moles of the element tellurium, Te? How many atoms is that? 127.60 g Te 8.44 mol Te x = 1080 g 1 mol Te 6.02 x 1023 atoms Te 8.44 mol Te x = 5.08 x1024 atoms Te 1 mol Te At STP, 6.81 moles of N2 gas will take up what volume? 22.4 L N2 6.81 mol N2 x = 153 L N𝟐 1 mol N2 How many moles of Cu(OH)2 are there in 83.5 g? 1 mole Cu(OH)2 83.5 g Cu(OH)2 x = 0.856 mol Cu(OH)2 97.57 g Cu(OH)2 What is the percent composition (rounded to the hundredths place) of: a. Mg(NO3)2 – Mass = 148.33 amu 24.31 amu Mg: 1 x 24.31 amu = 148.33 amu x100 = 16.39 % Mg N: 2 x 14.01 amu = 28.02 amu x100 = 18.89 % N 148.33 amu 96.00 amu O: 6 x 16.00 amu = 148.33 amu x100 = 64.72 % O b. Al2(SO4)3 – Mass = 342.17 amu 53.96 amu Al: 2 x 26.98 amu = 342.17 amu x100 = 15.77 % Al S: 3 x 32.07 amu = 96.21 amu x100 = 28.12 % S 342.17 amu 192.00 amu O: 12 x 16.00 amu = 342.17 amu x100 = 56.11 % O c. H2O – Mass = 18.02 amu 2.02 amu H: 2 x 1.01 amu = 18.02 amu x100 = 11.21 % H 16.00 amu 58. 59. Cl: 1 x 16.00 amu = 18.02 amu x100 = 88.79 % O Write the empirical formula for the following: a. FeS FeS b. Si2O4 A compound is composed of 40.00 % C, 6.72 % H and 53.29 % O. a. Find its empirical formula. 1 mol C C: 40.00 g C x 12.01 g C = 3.33 mol C / 3.33 mol = 1 H: 1 mol H 6.72 g H x 1.01 g H = 6.65 mol H / 3.33 mol = 2 SiO2 Empirical Formula – CH2O 1 mol O O: 53.29 g O x 16.00 g O = 3.33 mol O / 3.33 mol = 1 b. If the molar mass of the compound is 60.06 g/mol, what is the molecular formula? Molecular Formula 60.06 g/mol CH2O molar mass=30.03 g/mol, Empirical Formula = 30.03 g/mol = 2, Molecular Formula = C2H4O2 Final Review 9 60. 61. Write the name or formula for the following hydrates: Calcium Chloride Hexahydrate b. Barium hydroxide octahydrate Ba(OH)2 ∙ 8 H2O What is a mole ratio? How can it be determined? 62. a. CaCl2 ∙ 6H2O The mole ratio is the ratio between substances in a reaction. It is determined from the coefficients of the balanced reaction. Using the equation below: C2H4 (g) + 3 O2 (g) 2 CO2 (g) + 2 H2O (g) 63. a. How many moles of carbon dioxide are made with 6.33 moles of water? 2 mol CO2 6.33 mol H2O x = 6.33 mol H2O 2 mol H2O b. How many grams of water are made from 2.12 moles of ethylene (C2H4)? 2 mol H2O 18.02 g H2O 2.12 mol C2H4 x x = 76.4 g H2O 1 mol C2H4 1 mol H2O c. How many liters of carbón dioxide can be made with 66.2 L of oxygen? 2 L CO2 66.2 L O2 x = 44.1 L CO2 3 L O2 d. How many grams of oxygen are needed to produce 33.1 grams of ethylene? 1 mol C2H4 3 mol O2 32.00 g O2 33.1 g C2H4 x x x = 113 g O2 28.06 g C2H4 1 mol C2H4 1 mol O2 You collect 582 g of a product in a reaction. You calculated the theoretical yield to be 733 g. What is the percent yield in your reaction? actual 582 g x 100 = x 100 = 79.40 % yield theoretical 733 g What state(s) of matter: Percent Yield = 64. a. Is most compressible? b. Has the highest density? 65. d. Are fluids? Solid Gas and Liquid London dispersions are temporary dipole attractions between nonpolar substances and the weakest forces, dipole-dipole interactions are between polar substances, and hydrogen bonds are between polar compounds with N, O, or F and the strongest forces. What type of energy changes during a phase change? 67. Solid c. Has the lowest energy? Compare and contrast these intermolecular forces: London dispersion, dipole-dipole, and hydrogen bonds. 66. Gas During a phase change, the potential energy is changing, kinetic stays the same. What is STP? What are the conditions of STP? STP is standard temperature (0 °C) and pressure (1 atm). Final Review 10 68. What state change occurs when: a. A gas becomes a solid? b. A liquid becomes a gas? Deposition Boiling/Evaporation/Vaporization 69. Answer the following questions based on the phase diagram below: 70. a. Name points d & e on the phase diagram. d – triple point (all 3 states exist). e – critical point (liquid and gas indistinguishable – supercritical fluid). b. What state change occurs as you heat a substance from C to B on the phase diagram? Heating from C to B causes Boiling/Evaporation/Vaporization. c. What is the normal melting point of the substance above? The normal melting point is 60 °C for the substance above. Using the heating curve to the right: 71. 72. a. What state of matter is being heated at leg c? At leg c, the liquid is being heated. b. On which line is the substance melting? The substance is melting during leg b. What are the assumptions of the kinetic molecular theory? The kinetic molecular theory assumes that there are no interactions between particles, no volume from the particles, there are perfectly elastic collisions, and the temperature is proportional to kinetic energy. Perform the following pressure conversions: a. 685 mm Hg to atm 1 atm 685 mm Hg x = 0.901 atm 760 mm Hg b. 112 kPa to torr 760 torr 112 kPa x = 840. torr 101.3 kPa Final Review 11 73. If a gas at a pressure of 1.25 atm is compressed from 311 mL to 154 mL, what is the new pressure? Which law is this? P1V1 = P2V2; P2 = 74. P1 V1 (1.25 atm)(311 mL) = = 2.52 atm , Boyle's Law V2 0154 mL A tire at a temperature of 25 °C increases in pressure from 740 mmHg to 1125 mmHg. What is the new temperature? Which law is this? P1 P2 P2 T1 (1125 mmHg)(298 K) = ; T2 = = = 453 K , Gay-Lussac's Law. T1 T2 P1 740 mmHg 75. A gas takes up a volume of 17.3 liters, has a pressure of 2.30 atm, and a temperature of 299 K. If I raise the temperature to 350. K and lower the pressure to 1.5 atm, what is the new volume of the gas? Which law is this? P1 V1 P2 V2 (2.30 atm)(17.3 L) (1.5 atm)V2 = ; = ; V2 = 31.1 L , Combined Gas Law. T1 T2 299 K 350. K 76. If I have an unknown quantity of gas at a pressure of 1.20 atm, a volume of 31.0 liters, and a temperature of 87 °C, how many moles of gas do I have? Which law is this? PV (1.20 atm)(31.0 L) = = 1.26 mol , Ideal Gas Law RT (0.0821 L ∙ atm )(360. K) mol ∙ K Which will diffuse faster: He or N2? Why? PV = nRT ; n = 77. 78. What temperature is absolute zero? What happens at absolute zero? 79. 80. He will diffuse faster because it is lighter (smaller molar mass) than N2. Absolute zero is 0 K. At absolute zero, all matter has no kinetic energy and freezes. The substance being dissolved in a solution is the solute and the substance doing the dissolving is the solvent. What is the molarity of a 0.875 L solution with 21.2 g of lithium bromide? 21.2 g LiBr x 81. 1 mol LiBr mol 0.244 mol = 0.244 mol LiBr ; M = = = 0.279 M 86.84 g LiBr V 0.875 L How many moles of sodium chloride are needed to make 250 mL of a 2.5 M solution? mol = MV = (2.5 M)(0.25 L) = 0.625 mol 82. At 50°C, a solution contains 20 g of KCl in 100 g of water. According to the solubility curve, is the solution saturated, unsaturated, or supersaturated? 83. The solution would be unsaturated. According to the solubility curve, how much more KClO3 can be added if the solution is heated from 30°C to 70°C? 30 g – 10 g = 20 g Final Review 12 84. How much heat is needed to raise the temperature of 29.5 g of iron from 295 K to 365 K if the specific heat of iron is 0.450 J/g∙K? Q = m C ΔT = (29.5 g)(0.450 J/g∙K)(365 K – 295 K) = 929 J 85. Describe the properties of acids and bases below: Acid a. Taste Sour Bitter b. Ion released in water H+ OH- c. Reactivity with Metal Reactive Unreactive d. pH level 86. Base <7 >7 A solution has a pH of 3. a. What is the [H+]? [H+] = 1 x 10-3 M b. What is the pOH? pOH = 14 – pH = 14 – 3 = 11 c. What is the [OH-]? [OH-] = Kw 1 x 10-14 -11 M + = -3 = 1 x 10 [H ] 1 x 10 d. Is the solution more likely to be acetic acid or potassium hydroxide? 87. The solution is most likely acetic acid. Write the name or formula for the following acids: a. HNO3 b. Hydrofluoric acid c. H2S d. Sulfurous Acid Nitric Acid HF Hydrosulfuric Acid H2SO3 Look over your notes, assignment packets and these review questions. Good luck & Study! Study!! Study!!!