Chemistry Test 3 Past Paper PDF

# TEST 3 (Nine-Weeks Exam) ## Chapters 1-5 ### MULTIPLE CHOICE I: Write the letter of the correct choice in the blank. 1. What are the smallest particles into which an element may be broken down without changing the identity of the element? a. quarks b. nucleons c. atoms d. molecule...

# TEST 3 (Nine-Weeks Exam) ## Chapters 1-5 ### MULTIPLE CHOICE I: Write the letter of the correct choice in the blank. 1. What are the smallest particles into which an element may be broken down without changing the identity of the element? a. quarks b. nucleons c. atoms d. molecules 2. Which of the following does 1 millimeter of mercury (1 mmHg) equal? a. 1 torr b. 1 boyle c. 1 pascal d. 1 millibar 3. What is the number of protons in an atom? a. atomic mass b. mass number c. nuclear number d. atomic number 4. Which of the following does the standard atmosphere (atm) equal? a. 14.7 torr b. 670 torr c. 760 torr d. 1013 torr 5. What isotope is the atomic mass unit defined relative to? a. helium-3 b. hydrogen-1 c. carbon-12 d. oxygen-16 6. Which step of the scientific method involves thinking about nature to develop an idea about how something works? a. hypothesizing b. experimenting c. observing d. collaborating 7. What is a microsecond? a. 10⁹ s b. 10⁻⁶ s c. 10² s d. 10 s 8. What is standard temperature and pressure (STP)? a. 0 K and 760 torr b. 0 K and 1000 torr c. 273.15 K and 760 torr d. 273.15 K and 1000 torr 9. How many atoms are in exactly one mole of atoms? a. 1.602 x 10²² b. 6.022 x 10²¹ c. 6.604 x 10²³ d. 6.087 x 10²⁴ 10. Which of the following temperatures equals 0 K? a. -459.67°C b. -273.15°C c. -40.00°C d. 0.00°C ### MODIFIED TRUE/FALSE: If the statement is true, write *true* in the blank. If it is false, replace the *italicized* word(s) with the word(s) that will make the statement true. 11. The instrument used to measure atmospheric pressure is the *barometer*. 12. The amount of force exerted upon a surface per unit of area is *pressure*. 13. In the solid state of matter, particles have enough energy to *move freely* but not enough energy to overcome their attraction for each other. 14. How closely a measured value matches the actual value is *precision*. 15. The dense central portion of an atom is called the *core*. 16. The link between the microscopic and macroscopic levels of chemistry is *Avogadro's number*. 17. The formula of copper(II) chloride is *CuCl₂*. ### MATCHING: Match each reaction with the correct category. Answers may be used more than once. 18. 2 K(s) + I₂(g) → 2 KI **A. combination reaction** 19. 2 Al(s) + Fe₂O₃(s) → 2Fe(l) + Al₂O₃(s) **B. decomposition reaction** 20. Zn(s) + 2HCl(aq) → H₂(g) + ZnCl₂ (aq) **C. double-displacement reaction** 21. HCIO (aq) + KOH(aq) → H₂O(1) + KCIO₄ (aq) **D. single-displacement reaction** ### MULTIPLE CHOICE II: Write the letter of the correct choice in the blank. 22. What is the molar mass of diborane (B₂H₆)? (m₁₁ = 11 u; m₁ = 1 u) a. 6 g/mol b. 12 g/mol c. 22 g/mol d. 28 g/mol 23. Which law implies that, at constant temperature and pressure, the molar volume of an ideal gas is constant? a. Avogadro's law b. Boyle's law c. Graham's law d. combined gas law 24. How many significant figures does the number 68,080 have? a. 2 b. 3 c. 4 d. 5 25. A sample of hydrogen gas is prepared by water displacement at a pressure of 760. torr and a temperature of 22°C. If the vapor pressure of H₂O at that temperature is 20. torr, what is the partial pressure of the hydrogen? a. 740. torr b. 760. torr c. 780. torr d. 800. torr 26. Which of the following statements describes the theoretical behavior of any ideal gas as it is cooled to absolute zero (0 K) at constant pressure? a. The volume decreases until the gas condenses at 5.7 K. b. The volume decreases but rapidly increases to infinity at 1.0 K. c. The volume decreases until the gas particles disintegrate at 3.4 K. d. The volume decreases until it becomes zero at 0 K. 27. Which of the following is not an assumption of the kinetic theory of matter? a. Gas molecules are in constant, rapid motion. b. Gas molecules are negligible in volume compared to the volume of the gas as a whole. c. Gas molecules are weakly but significantly attracted to each other. d. The kinetic energy of gas molecules is directly related to temperature. 28. Which of the following statements about the gold(III) ion (Au³⁺) is true? a. Gold(III) has three fewer electrons than a neutral gold atom. b. Gold (III) has three fewer protons than a neutral gold atom. c. Gold (III) has three more electrons than a neutral gold atom. d. Gold(III) has three more protons than a neutral gold atom. 29. What does 1.5 m equal? a. 15 km b. 15 mm c. 15 dm d. 15 cm 30. Which of the following is an example of a chemical change? a. melting wax b. mixing paint c. bending steel d. browning meat 31. In the open-end manometer shown below, what is the pressure of the gas (P)? a. 250. mmHg b. 500. mmHg c. 750. mmHg d. 1000. mmHg ### SHORT ANSWER: Write the correct answer in the blank. 38. When food coloring dye is dropped into water, the dye spreads throughout the water until they are evenly mixed. Name the molecular process that causes the dye and water to mix. **Diffusion** 39. What element does the symbol Pb represent? **Lead** ### BALANCING EQUATIONS: Balance the equation in the space provided. 36. H₂(g) + N₂(g) → **3**NH₃(g) 37. **2**Al(s) + **6**HCl(aq) → **2**AlCl₃ (aq) + **3**H₂(g) ### PROBLEMS: Solve the problem; show your work in the space provided and circle the answer. Express the answer using proper significant figures and units. 40. What quantity is the ratio of mass to volume? **Density** 41. Which of the following gases would you expect to diffuse fastest: H₂, CH₄, or C₂H₄? **H₂** 42. What is the symbol of the element silicon? **Si** 43. Name the compound CaCO₃. **Calcium carbonate** 44. Name the compound HF. **Hydrogen fluoride** 45. Name the negatively charged subatomic particles in an atom. **Electrons** 46. A sample of hydrogen gas has a volume of 4.4 L at a pressure of 800. torr. If the pressure decreases to 400. torr, what will the new volume be? ``` P1V1=P2V2 V2=P1V1/P2 V2= (800. torr) * (4.4 L) / (400. torr) V2= 8.8 L ``` 47. A sample of nitrogen occupies 1.00 L at a temperature of 250. K. What volume would it occupy at 1500. K? ``` V1/T1=V2/T2 V2=V1*T2/T1 V2= (1.00 L) * (1500 K) / (250 K) V2= 6.00 L ``` 48. A typical weather balloon contains approximately 563 L of hydrogen gas when it is released. If the temperature and pressure at the surface are 288 K and 1.00 atm when the balloon is released, what will its volume be at 32.0 km above the surface, where temperature and pressure are 229 K and 8.57 x 10⁻³ atm? ``` P1V1/T1=P2V2/T2 V2=(P1V1*T2)/(P2T1) V2= (1.00 atm)*(563 L)*(229 K) / (8.57 x 10⁻³ atm)*(288 K) V2= 5.5 x 10^4 L ``` 49. Sodium metal and chlorine gas can be produced industrially by passing an electric current through molten sodium chloride: 2 NaCl(l)→2 Na(l) + Cl₂(g) What volume of Cl₂ at 293 K (20.°C) and 1.00 atm can be obtained from 68.0 g NaCl using this reaction? (MNaCl = 58.44 g/mol; R = 0.0821 L-atm/[K-mol]) ``` n=m/M n=(68.0 g) / (58.44 g/mol) n=1.16 mol NaCl 2 mol NaCl : 1 mol Cl₂ --> 1.16 mol NaCl = 0.58 mol Cl₂ PV=nRT V=(nRT)/P V=(0.58 mol)*(0.0821 L-atm/[K-mol])*(293 K) / (1.00 atm) V= 14 L ```