EXAM #1 CHEM 161 1. Which of the following is a property of both liquids and gases? a. a definite volume, but not a definite shape b. are compressible c. particles are free to move (fluid) d. particles are very far apart e. liquids and gases have no similarities 2. A sample of matter does not a variable composition and can be separated into simpler substances. This must be a. a homogeneous mixture b. an element c. a compound d. an element or a compound e. a heterogeneous mixture 3. Which of the following is a pure substance? a. sea water b. sugar c. air d. zinc e. both b and d 4. Which of the following is an example of a physical change? a. adding chocolate syrup to milk to make chocolate milk b. warming a block of solid carbon dioxide to convert it to a gas c. neutralizing “stomach” acid by taking an antacid d. both a and b e. all of the above are examples of chemical changes 5. Which of the following statements about energy is FALSE? a. Energy can be converted from one type to another. b. The total energy of a system remains constant. c. Kinetic energy is the energy associated with its position or composition. d. Energy is the capacity to do work. e. Systems tend to change in order to lower their potential energy. 6. How many significant figures are in the number 0.000230? a. 2 b. 3 c. 4 d. 5 e. 6 7. What would be the correct answer to report for the following calculation? (96.532 – 96.232) ÷ 135.6 = a. 0.002 b. 0.0022 c. 0.00221 d. 0.002212 e. 0.00221248. Which of the following is an example of a measured number? a. 50.0mL of water in a graduated cylinder b. the number of pages in this exam c. the number of centimeters in a meter d. both a and c e. none of these – all of them are exact numbers 9. A bike rider has an average speed of 22 miles per hour. At this speed, how long would it take him to complete a 75 kilometer route? a. 2.1 hours b. 3.4 hours c. 4.5 hours d. 45 minutes e. 1.0 x 103 hours 10. Which of the following is the heaviest? a. 100. pounds of Aluminum (D = 2.70 g/mL) b. 3.00 L of Mercury (D = 13.6 g/mL) c. 1.00 ft3 of Cement (D = 3.00 g/mL) d. 40.0 kg of Lead (D = 11.4 g/mL) e. 25.0 gallons of Gasoline (D = 0.66 g/mL) 11. An unknown metal sphere has a radius of 2.5 inches and a mass of 9.55 kilograms. What is the density of this metal sphere in grams per cubic centimeter? The volume of a sphere is: V = (4/3) π r3. a. 150 g/cm3 b. 14 g/cm3 c. 8.9 g/cm3 d. 7.1 g/cm3 e. none of the above 12. All samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements. Which law does this refer to? a. Law of Definite Proportions b. Law of the Conservation of Mass c. Law of Modern Atomic Theory d. Law of Multiple Proportions e. First Law of Thermodynamics 13. A compound containing nitrogen and oxygen is found to contain 2.86g of O for every 1.00g of N. Which of the following samples must be the same compound? a. 5.00g N, 5.71g O b. 7.00g N, 4.00g O c. 3.33g N, 7.61g N d. 7.25g N, 20.7g O e. none of the above14. Millikan’s oil drop experiment was used to discover a. the structure of the atom. b. the neutron. c. the charge of a single electron. d. the existence of atoms. e. the proton. 15. An isotope of Fe has 33 neutrons in its nucleus. What is its mass number? a. 26 b. 33 c. 55.847 d. 52 e. 59 16. This element is in period 3 and a poor conductor. This element could be: a. B b. Mg c. P d. Sc e. either b or c 17. Which of the following elements is a non-metal? a. H b. Br c. Zn d. Na e. both a and b 18. The number of protons, neutrons, and electrons present in an atom of 60Ni+2 is, respectively, a. 28, 60, 26 b. 28, 32, 26 c. 28, 32, 30 d. 30, 30, 28 e. 28, 32, 28 19. The element Rhenium, with an atomic mass of 186.207amu, has two naturally occurring isotopes, 185Re and 187Re. The 187Re isotope has a mass of 186.956amu and a percent abundance of 62.60%. What is the mass of the 185Re isotope? a. 183.925amu b. 186.2amu c. 69.17amu d. 184.953amu e. not enough info 20. A pure sample of Silver (Ag) contains 2.52 x 1024 atoms. What is the mass in grams of this sample? a. 108g b. 2.72 x 1026 g c. 4.19g d. 452g e. none of the above 21. Which of the following is an example of a molecular element? a. Na b. P4 c. SF2 d. MgCl2 e. both a and b22. What is the correct name for compound SF4? a. sulfur fluoride b. sulfur(IV) fluoride c. sulfur tetrafluoride d. sulfur(IV) fluoride e. sulfate 23. How many moles does a mass of 32.6g of iron(III) chloride represent? a. 0.201mol b. 0.161mol c. 0.119mol d. 0.357mol e. 4.98mol 24. A sample containing 6.02 x 1023 molecules of nitrogen trifluoride will have a mass of a. 1.00g b. 71.0g c. 1.18 x 10-22 g d. 4.27 x 1025 g e. 99.0g 25. Which of the following samples contains 6.02 x 1023 atoms of oxygen? a. 44.0g of CO2 b. 1.00mol of NO2 c. 30.0g of C6H12O6 d. 16.0g of CH3OH e. both a and b 26. What is the mass percentage of nitrogen in the compound ammonium nitrate? a. 17.5% b. 35.0% c. 58.3% d. 29.2% e. none of the above 27. Sulfur and chlorine react to form several different compounds whose general formula is SxCly. In an experiment, 0.250g of Sulfur is reacted with chlorine producing 0.803g of the compound SxCly. A second experiment shows that the molecular weight of the compound is approximately 205amu. What is the molecular formula for this compound? a. SCl2 b. SCl4 c. S2Cl4 d. SCl5 e. S2Cl6 28. Combustion analysis of an unknown compound containing only carbon and hydrogen produced 0.2845 g of CO2 and 0.1451 g of H2O. What is the empirical formula of the compound? a. CH2 b. C2H5 c. C4H10 d. C5H2 e. none of the above 29. When the following reaction is balanced, the sum of ALL the coefficients will be __PCl5 + __H2O → __H3PO4 + __HCl a. 4 b. 9 c. 11 d. 21 e. none of the above 30. When the following equation is balanced, the coefficient for O2 is C4H8O2 + __O2 → CO2 + H2O a. 3 b. 5 c. 6 d. 7 e. 1131. Which of the following is an example of an alkene? a. CH4 b. CH3CH=CHCH3 c. CH3CCH d. CH3CH2CH3