1. CHEMISTRY 2000 Released Test Items Virginia Department of Education

2. 1. The following data are obtained in the laboratory: (a) the mass of a clean, dry 250 mL beaker (b) the mass of the same beaker containing an unknown quantity of magnesium sulfate. The mass of the magnes- ium sulfate is obtained by subtracting (a) from (b). Which of the following will provide the most accurate results? 1.Measurements should be taken using the same balance. 2.The temperature of the room must remain constant. 3.The barometric pressure should be recorded. 4.A calculator should be used to subtract a from b.

3. 2. Many reactions are taken to completion by hearing the reaction mixture in a test tube. Each of the following would be a safe practice except--- 1.Heating the test tube gently to prevent the solution from boiling over 2.Pointing the test tube away from others so that no one is injured. 3.Placing a stopper in the test tube to prevent gas from escaping 4.Holding the test tube with test tube clamps to avoid touching hot objects.

4. 3. A student wants to study the effects of volume on gas pressure. During his experiment, he recorded the above data. How could he now study the effects of temperature on gas pressure? 12345 1.Vary the temperature but keep the gas volume constant 2.Vary the volume of the gas only 3.Vary the pressure and temperature of the gas 4.Vary the temperature and volume of the gas

5. 4. Which salt’s solubility in water is least affected by temperature? 12345 1.NaCLO 2 2.KNO 3 3.KBr 4.NaCL

6. 5. A student conducted an experiment to study the effects of temperature this chemical reaction. The student’s experimental conditions are shown below. Which of the following would improve the student’s experimental design? 1.Use the same amount of catalyst in all trials. 2.Keep all tubes at 18°C. 3.Keep the reaction time constant. 4.Decrease the quantity of reactants. 12345

7. 6. A student massed a piece of iron on a balance. The most sensitive beam was marked off in 0.1g. intervals. The student reported the iron’s mass as 12.34g. Which of the digits in the measurement is estimated? 1.1 2.2 3.3 4.4 12345

8. 7. A student measured the temperature of a boiling solution and found it to be 56.0°C at standard pressure. The theoretical temperature of the boiling solution is 55°C. What is the percent of error in the student’s measurement? 12345 1.18% 2.1.8% 3.0.18% 4.0.018%

9. 8. How many significant digits are in 0.003450? 1.3 2.4 3.6 4.7 12345

10. 9. A 0.500L solution of 6M HCl has to be made. How much 12M HCl is needed? 12345 1.0.250 L 2.2.50 L 3.25.0 L 4.2500 L

11. 10.Generalization: As temperature increases, the solubility of a gas in a liquid usually decreases. Which graph best represents the above generalization? 1.2. 3.4. 12345

12. 11.The data indicates that____ Protons NeutronsElectrons Substance A 888 Substance B 898 12345 1.A and B are isotopes of the same element. 2.A and B are different elements 3.A has a greater charge than B 4.A is more reactive than B

13. 12. A neutral atom of calcium has 20 electrons. Calcium forms a 2+ ion. How many electrons does a calcium ion have? 12345 1.2 2.18 3.20 4.22

14. 13.According to their placement on the periodic table, which elements would have the most similar atomic structures? 12345 1.Sodium and scandium 2.Sodium and barium 3.Sodium and potassium 4.Sodium and aluminum

15. 14. Oxygen and sulfur are in the same group (16) in the periodic table. This means that, in general, oxygen and sulfur___ 12345 1.Will react only with each other 2.Undergo similar reactions with other elements 3.Can only react with elements in group 16 4.Combine only with elements in periods of 4 or higher

16. 15. According to the periodic table, which of the following series of elements is ordered according to decreasing reactivity? 1.He, Cs, Si, Mg 2.Cs, Mg, Si, He 3.Si, He, Cs, Mg 4.Mg, Si, Cs, He 12345

17. 16. With n representing the outermost energy level, the electron configuration for that level for elements in Group 14 is___ 12345 1. ns 2 np 1 2. ns 2 np 2 3. ns 2 np 3 4. ns 2 np 4

18. 17. An alkali metal will most readily react with___ 12345 1.Another alkali metal 2.An alkaline earth metal 3.A halogen 4.A noble gas

19. 18. Neils Bohr’s contribution to modern atomic theory was the proposition that___ 12345 1.Each atom has a specific number of positive charges 2.An atom has electrons in discrete energy levels 3.Electrons have a definite mass that can be computed 4.Atomic mass is determined by the number of protons and neutrons in an atom

20. 19. O 2, N 2, Cl 2, and I 2 are examples of ___ 1.Diatomic molecules 2.Compounds 3.Ionic compounds 4.atoms 12345

21. 20. Which of these is the correct name for KBr? 1.Potassium bromine 2.Potassium bromide 3.Potassium bromate 4.Potassium bromite 12345

22. 21. Which of the following is a balanced equation? 12345 1.C 3 H 8 (g)+O 2 (g) →CO 2 (g) + H 2 0(g) 2.C 3 H8(g)+O 2 (g)→3CO 2 (g)+ H 2 O (g) 3.C 3 h 8 (g)+2O2(g)→3CO 2 (g)+ 4H 2 O(g) 4.C 3 H 8 (g)+5O 2 (g)→3CO 2 (g)+ 4H 2 O(g)

23. 22. Iron (III) chloride + sodium carbonate →Iron (III) carbonate + sodium chloride Which of these is the balanced equation for the reaction described? 1.FeCl 3 +Na2CO 3 →Fe 2 (C O 3 ) 3 +NaCl 2.2FeCl 3 +2Na 2 CO3→3Fe 2(CO 3 ) 3 +3NaCl 3.2FeCl 3 +3Na 2 CO3→Fe 2 ( Co 3 ) 3 +6NaCl 4.3FeCl 3 +2Na 2 CO 3 →Fe 2 ( CO 3 ) 3 +6NaCl 12345

24. 23. How many different elements are in ammonium hydroxide (NH 4 OH)? 1.2 2.3 3.4 4.7 12345

25. 24. Which of the following best represents the reaction between sulfuric acid and calcium hydroxide? 1.H 2 SO 4 +Ca(OH) 2 →CaS O 4 +H 2 O 2.HSO 4 +CaOH→CaSo 4 + H 2 O 3.H 2 So 4 +Ca(OH) 2 →CaSO 4 +2H 2 O 4.H 2 So 4 +2Ca(OH) 2 →2Ca So 4 +3H 2 O 12345

26. 25. :N :: N: According to the Lewis diagram, a nitrogen molecule has a___ 12345 1.Bent structure and a double bond 2.Linear structure and a triple bond 3.Polar structure and a triple bond 4.Circular structure and an ionic bond

27. 26. The name for NH 4 F is____ 12345 1.Ammonia fluoride 2.Ammonium fluoride 3.Nitrogen tetrahydrogen fluoride 4.Ammonium fluorine

28. 27. The electron configuration for phosphorous is 1s 2 2s 2 2p 6 3s 2 3 p3. What is the Lewis electron dot diagram for phosphorous? 12345 1.A 2.B 3.C 4.D

29. 28. Cobalt, a transition metal, can have an oxidation number of either 2+ or 3+. Which of these represents the two possible chemical formulas for the chemical combination of cobalt with oxygen? 12345 1.CoO, Co 2 O 3 2.CoO 3, Co 3 O 2 3.Co 2 O 3, Co 3 O 2 4.CoO, Co 3 O 2

30. 29. Which statement describes the above equation: 1.Magnesium transfers an electron to each atom of the iodine molecule 2.The iodine molecule transfer two protons to magnesium. 3.Magnesium shares an electron with iodine 4.Iodine becomes a free monatomic element. 12345

31. 30. Sodium iodide exhibits what type of bond? 12345 1.Covalent 2.Ionic 3.Hydrogen 4.Metallic

32. 31. Which of the following reactions is a decomposition reaction? 12345 1.S 8 + 80 2 →8SO 2 2.O 2 + 2H 2 O→2H 2 O 2 3.2KClO 3 →2KCl + 3O 2 4.2Na + 2AgCl→2NaCl + 2Ag

33. 32. Which of the following reactions is a neutralization reaction? 1.2AgNO3 +Cu→Cu(NO 3 ) 2 +2Ag 2.KOH+HNO 3 →KNO 3 +H 2 O 3.C + O 2 →CO 2 4.4Fe(OH) 2 + 2H 2 O 2 →4Fe(OH) 3 12345

34. 33. Which of the following reactions is an example of a single-replacement reactions? 12345 1.2AgNO 3 +Cu→Cu(N) 3 ) 2 + 2Ag 2.NaOH+HCl→NaCl+H 2 O 3.CO2→C+O 2 4.4Fe(OH) 2 +O 2 →4Fe(OH) 3

35. 34. When seltzer tablets are placed in a glass of water, they fizz as they release a gas. To increase the speed that gas is released from each tablet, it would be best to increase the___ 12345 1.Volume of the glass 2.Temperature of the water 3.Amount of water 4.Hardness of the water

36. 35. What is the mass of one mole of S 8? 1.32.1 mg 2.32.1 g 3.257 g 4.4.8 x 10 24 g 12345

37. 36. What is the mass of 2 moles of HgO? 12345 1.108 g 2.217 g 3.323 g 4.433 g

38. 37. One mole of which of these compound contains two moles of hydrogen atoms? 12345 1.CH 4 2.H 2 s 3.NaOH 4.NH 3

39. 38. A student has one mole of an unknown compound in a test tube. The mass of the compound is 58.5g. The compound could be___ 1.CaCl 2 2.NaCl 3.AgNO 3 4.CuCl 12345

40. 39. To produce 12 moles of water, how many moles of oxygen gas are needed? 2C 2 H + 7O 2 →4CO 2 + 6H 2 O 12345 1.2 2.7 3.9 4.14

41. 40. The moles of hydrogen and ten moles of iodine were put into a sealed 1-liter container at 490°C and allowed to react. After a while, there were still small amounts of unreacted hydrogen and iodine, but the hydrogen iodide concentration became constant. This is because____ 1.There was not enough hydrogen to react with all of the iodine 2.The hydrogen iodide was reacting with the container 3.Iodine loses its reactivity at high temperatures 4.The reaction reached a state of equilibrium 12345

42. 41. A solution of unknown pH was tested with two indicators. Methyl orange turned yellow and methyl red turned red. Which of these could be the pH of the solution? 1.3.0 2.4.0 3.4.6 4.6.2 12345 IndicatorpH Rang e Color if pH below range Color if pH above range Cresol red0.2-1- 8 redyellow Methyl orange 3.2- 4.4 redyellow Methyl red4.8- 6.0 redyellow Litmus5.5- 8.0 redblue Bromothym ol blue 6.0- 7.6 yellowblue Phenol red6.6- 8.0 yellowred Thymol blue8.0- 9.6 yellowblue phenolphtha lein 8.2- 10.6 colorles s red

43. 42. Which of the following is not a base? 12345 1.Al(OH) 3 2.Ca(OH) 2 3.CaSO 4 4.KOH

44. 43.A sample of nitrogen gas is collected over water at 20°C. The vapor pressure of water at 20°C is 18 mmHg. What is the partial pressure of the nitrogen if the total pressure is 765 mmHg? 12345 1.18 mmHg 2.747 mmHg 3.765 mmHg 4.783 mmHg

45. 44. A gas has a volume of 50.0 cm 3 at a temperature of -73°C. What volume would the gas occupy at a temperature of -123°C if the pressure stays constant? 12345 1.3.75 cm 3 2.5.0 cm 3 3.37.5 cm 3 4.50.0 cm 3

46. 45. Ideal Gas Law constant = 8.31dm 3 kPa/K.mol How many moles of CO 2 are there in a 50.0 dm 3 sample of the gas at pressure of 100.0 kPa and a temperature of 50°C? 12345 1.1.20 moles 2.1.86 moles 3.2.0 moles 4.12.0 moles

47. 46. One way to increase the volume of the gas in the balloon in the diagram is to___ 1.Cool the gas in the balloon only 2.Increase the temperature of the water 3.Push the balloon farther down into the water bath 4.Seal the top of the water bath 12345

48. 47Which phase change involves the absorption of heat? 12345 1.Gas to liquid 2.Liquid to solid 3.Liquid to gas 4.Gas to solid

49. 48. What probably causes chloroform to have the lowest heat of vaporization? 1.Smallest size of the molecules listed 2.Smallest mass of the molecules listed 3.Smallest intermolecul ar forces of attraction 4.Fewest number of bonds 12345 SubstanceHeat of Vaporization at the boiling point Water (H 2 O) 539 calories per gram Alcohol (CH 3 Ch 2 OH ) 204 calories per gram Chloroform (CHCl3) 59 calories per gram

50. 49. How many calories are required to raise the temperature of 105g of water from 30.0°C to 70.0°C? 12345 1.1.05 X 10 3 2.2.10 X 10 3 3.4.20 X 10 3 4.8.40 X 10 3

51. 50. A student needed to dissolve a substance that she knew was soluble in water. According to the chart, which other solvent would most likely dissolve the substance. 12345 1.Benzene 2.Methanol 3.Hexane 4.Octane