Chemistry Exam Practice PDF

## Paige This is a compilation of years of review problems. Some problems are no longer applicable. Please refer to the "Breakdown" before doing these problems. ### Semester 1 Final Exam Review Packet ### Unit 1: Introduction to Chemistry 1. Write the following in scientific notation: - a. 0.0...

## Paige This is a compilation of years of review problems. Some problems are no longer applicable. Please refer to the "Breakdown" before doing these problems. ### Semester 1 Final Exam Review Packet ### Unit 1: Introduction to Chemistry 1. Write the following in scientific notation: - a. 0.00015 - b. 1500000 2. Indicate the correct number of significant digits for the following measurements: - a. 0.0018 m - b. 1.0001 g - c. 50.00 cm - d. 0.030 3. Change each of the following answers to the correct number of significant digits: - Example: 2.5 cm x 483.18 cm = 1207.95 answer: 1200 - a. 21.18 cm x 1.5 cm = 31.77 - b. 305 g + 23 mL = 13.26087 - c. 2.25 L + 0.007 L = 2.257 - d. 12.11 cm - 9.009 cm = 3.102 4. Indicate whether the following is a physical or chemical change: - a. peeling an orange - b. lighting a candle - c. barbecuing a steak - d. cutting a steak - e. freezing water - f. crushing rocks - g. boiling water - h. tarnishing brass. 5. Indicate whether the following is describing a chemical or physical property: - a. Aluminum is a silvery metal with a density of 2.7 g/mL - b. Metals are good conductors of heat and electricity. - c. Alkalis react readily with halogens forming salts. - d. Alkaline earth metals form compounds with halogens with the general formula MH2.  - e. More substances dissolve in water than any other solvent. - f. All the noble elements are in the gas phase. 6. Write formulas for the following ionic and molecular compounds. Use ion charges to predict the formulas for the ionic compounds. - a. potassium fluoride - b. barium chloride - c. dihydrogen sulfide - d. sodium oxide - e. calcium phosphate - f. diphosphorus pentaoxide - g. lithium hydroxide - h. chromium(II) chloride - i. barium sulfide 7. What separation technique should be used for the following in order to keep all components? - a. Alcohol and water - b. sand, salt and water - c. a precipitate - d. silver as a product from Cu reacting with AgNO3 | Group A | Group B | Group C | Group D | Group E | |---|---|---|---|---| | density (g/mL) | density (g/mL) | density (g/mL) | density (g/mL) | density (g/mL) | | 4.4 | 4.7 | 4.8 | 4.8 | 4.8 | | 4.5 | 4.9 | 4.8 | 4.9 | 4.9 | | 4.5 | 4.6 | 4.9 | 5.0 | 4.6 | | 4.6 | 4.6 | 4.8 | 4.6 | 4.7 | | 4.5 | 4.8 | 4.8 | 4.9 | 5.0 | 8. If the accepted density of the metal is 4.5 g/mL, which of the groups had the highest accuracy? - a. Group A - b. Group B - c. Group C - d. Group D - e. Group E 9. Which of the groups had the highest precision? - a. Group A - b. Group B - c. Group C - d. Group D - e. Group E 10. Group B has an average density of 4.7 grams/ml. What is the percent error if the accepted density is 4.5 g/ml? ### Unit 2 Types of Chemical Reactions 11. Which of the following are elements, compounds, homogeneous mixture, heterogeneous mixture? - a. oil and vinegar salad dressing - b. salt water - c. air - d. bronze - e. gasoline 12. Which of the following are qualitative observations, quantitative observations, inferences/interpretations - a. The smoke was reddish-brown - b. Colorless bubbles of gas were released that were likely oxygen gas - c. The mass of the product was 12.34 grams - d. The temperature of the room was 25°C 13. A red powder, consisting of identical red particles, is strongly heated in a test tube. Silvery droplets form at the mouth of the test tube and oxygen gas escapes into the air. The original substance was most likely: - a. an element - b. a compound - c. a mixture - d. a solution - e. both (c) and (d) 14. Which of the following statements about mixtures and pure substances is FALSE? - a. Mixtures can be easily separated. - b. Compounds lose the properties of the original substances. - c. Mixtures retain the properties of the original substances. - d. Homogenous solutions are pure substances. | Symbol | Protons | Neutrons | Electrons | Mass number | |---|---|---|---|---| | 4 He | 2 | 2 | 2 | 4 | | | 20 | 21 | 20 | 41 | 15. Fill in the chart below with the appropriate numbers for neutral atoms: | Symbol | Number of protons | Number of neutrons | Number of electrons | Atomic number | Mass number | |---|---|---|---|---|---| | 56 Fe3+ | 26 | - | - | 26 | -| | 16 O2- | 8 | - | 10 | - | - | | 8 O | - | - | 8 | - | - | ### Unit 3 Electrons in Atoms 1. What is an emission spectrum? 2. How is the energy, frequency and wavelength related to each other? Questions 3-6 refer to the following electromagnetic waves: - a. microwaves - b. radio waves - c. infrared - d. gamma - e. red - f. ultraviolet - g. green - h. blue 3. Which of the above are visible? 4. Order from lowest to highest frequency. 5. Order from lowest to highest energy. 6. Order from smallest to longest wavelength. 7. What is wrong if anything with the following descriptions of an orbital? - a. An orbital is a ball of uniform density. - b. An orbital is a solar system, like a planet circling the sun at a fixed distance. - c. An orbital tells you exactly where an electron can be found. - d. An orbital can accommodate only one electron. - e. Orbitals are regions of space in which electrons are likely to be found 8. Write the electron configuration for the following: - a. Na - b. Na+ - c. Rb+ - d. Br - e. Kr - f. O - g. N - h. Al - i. Al3+ - j. Ca2+ ### Unit 4 Periodicity 1. Which of the following is/are TRUE about Mendeleev's periodic table? - a. I only - I. The elements were arranged in order of increasing atomic mass. - II. Blanks were left on it for undiscovered elements. - III. Consisted of both elements and compounds. - b. III only - c. I and II only - d. I, II, and III 2. The modern periodic table is arranged in order of increasing: - a. atomic mass - b. atomic number - c. atomic size - d. atomic radius 3. On the periodic table, which of the following have similar chemical properties? - a. families - b. periods - c. blocks - d. sets For questions 4-8, match the element given with one of the following: - a. Alkali Metal - b. Alkali earth Metal - c. Halogen - d. Noble gas - e. Transition element | Element | | |---|---| | Calcium | a | | Neon | b | | Flourine | c | | Titanium | e | | Sodium | d | 9. Which of the following does describe most metals? - a. Shiny when smooth and clean. - b. Malleable and ductile. - c. Poor conductors of heat and electricity. - d. Solid at room temperature. 10. When Calcium reacts with oxygen it forms magnesium oxide (CaO). When Barium reacts with oxygen, what would be the chemical formula for the resulting product? - a. BaO2 - b. BaO - c. Ba2O - d. not enough information 11. Which of the following trends decreases going down the periodic table? - a. I only - I. Atomic Radii - II. Electronegativity - III. Ionization Energy - b. II only - c. II and III only - d. I, II, and III 12. The correct formula and charge of a chlorine atom is: - a. Cl - b. Cl2 - c. Cl - - d. Cl+ 13. A certain element forms an ion with a +1 charge. What is the number of electrons in the outermost (valence) shell of this element? - a. 2 - b. 1 14. Which of the following has the highest ionization energy? - a. Cs - b. K - c. Br - d. F 15. Which of the following statements about alkalis and halogens is TRUE going down the periodic table? - a. The reactivity of alkalis and halogens both increase. - b. The reactivity of alkalis and halogens both decrease. - c. The reactivity of alkalis decrease and halogens increase. - d. The reactivity of alkalis increase and halogens decrease. 16. What are the trends for the halogens in terms of - a. Melting point (of the free element) - b. Electronegativity - c. Chemical reactivity with metals 17. When phosphorus reacts to form a stable compound, it would be isoelectronic with - a. krypton - b. tin - c. neon - d. argon 18. Which of the following is the correct electron configuration for Ti2+? - a. [Ar] 4s2 - b. [Ar] 4s23d2 - c. [Ar] 3d2 - d. [AR] 19. Which of the following are larger than the neutral atoms from which they are formed? - a. positive ions - b. negative ions - c. both a and b - d. neither a nor b 20. Potassium has a lower first ionization energy than lithium BECAUSE? 21. The lithium atom has a larger atomic radius than fluorine BECAUSE? ### Unit 5 Bonding 1. Fill in the chart below: | Molecule | Lewis structure | Geometry | Polarity | IMF | |---|---|---|---|---| | F2S | | | | | | CCl4 | | | | | | SiS2 | | | | | | PF3 | | | | | 2. Identify the bonding between each pair as ionic, polar covalent, or non-polar covalent, - a) O and O - b) C and Cl - c) Cu and Zn - d) Li and Br 3. What is the definition of boiling point? 4. What are the two factors that affect vapor pressure? 5. Which of the following solids is conductive and ductile? - a) Metallic - b) Ionic - c) Network covalent - d) Molecular ### Unit 6 Gases 3.a 4b 5d 6. c 7. e 8. a 9. a, b, d 10. b 11 c 12 d 13 b 14 d 15 d 16 a. increases b. decreases c. decreases 17. d 18 [Ar] 3d² 19. b 20. Potassium has a lower first ionization energy because the electrons in potassium are further from the pull of the nucleus or on higher levels and the inner electrons create a shielding effect 21. Lithium has fewer electrons pulling on its electrons and the electrons are on the same level as fluorine so shielding is not a factor. ### Unit 5 Bonding 1. F2S is bent and polar, dip-dip CCl4 is tetrahedral and non-polar, disp SiS2 is linear and non-polar, disp PF3 is pyramidal and polar, dip-dip 2. a. non-polar covalent b. polar covalent c. metallic d. ionic 3. Temperature at which the vapor pressure equals the external pressure 4. Temperature and IMF's 5. a ### Unit 6 Gases la. 293K b. .99 atm 2. a. 2.14L b. 8 atm c. 5.17 atm d. 3.5 atm 3 think about motion of molecules and the gas laws 4. 1.68 atm each all the same because same number of moles 29.9 grams of CO2, 1.36 grams of H2, 21.8 grams of O2 5. H2 shrinks the fastest, H2/CO2= 4.69 x faster 6. 24.5 liters. Larger than 22.4 due to increase in T thus V up. ### Unit 7 Moles la. .429 mol b. 860 grams c. 2.75 x 10 22 molecules 2a. 2 b. 6 c. 3 3. 2 moles of C, 4 moles of Hydrogen and 2 moles of oxygen 5.35.48 ### Exam Section B Review 1. What is the pressure of a container when 5.6g of nitrogen gas is placed into a 4.2L container at 23°C? 2. Does sodium or rubidium have a lower ionization energy? Briefly explain 3. Put the following in order of increasing VP. - H2O - NC13 - C3H8 - C4H10 ### Answers 1. 879.5mmHg 2. rubidium - Higher energy level, so further away and more shielding - More nuclear charge, which is counteracted by shielding - Weaker force, less energy to remove electrons, lower ionization energy 3. H2O <NCl3 < C4H10< C3H8