1. Base your answer to the following question on the...

1. Base your answer to the following question on the information below

The Balmer series refers to the visible bright lines in the spectrum produced by hydrogen atoms. Thecolor and wavelength of each line in this series are given in the table below.

On the diagram above draw four vertical lines to represent the Balmer series.

2. Base your answer to the following question on the information below.

The accepted values for the atomic mass and percent natural abundance of each naturally occurringisotope of silicon are given in the data table below.

Determine the total number of neutrons in an atom of Si-29.

3. Base your answer to the following question on the following information.

In a laboratory, a glass tube is filled with hydrogen gas at a very low pressure. When a scientist applies ahigh voltage between metal electrodes in the tube, light is emitted. The scientist analyzes the light with aspectroscope and observes four distinct spectral lines. The table below gives the color, frequency, andenergy for each of the four spectral lines. The unit for frequency is hertz, Hz.

On the grid, plot the data from the data table for frequency and energy. Circle and connect the points,including the point (0,0) that has already been plotted and circled for you.

4. Base your answer to the following question on the article below, the Reference Tables for Physical Setting/Chemistry, and your knowledge of chemistry.

In the 1920s, paint used to inscribe the numbers on watch dials was composed of a luminescent(glow-in-the-dark) mixture. The powdered-paint base was a mixture of radium salts and zinc sulfide. Asthe paint was mixed, the powdered base became airborne and drifted throughout the workroom causingthe contents of the workroom, including the painters' clothes and bodies, to glow in the dark. The paint is luminescent because radiation from the radium salts strikes a scintillator. A scintillator isa material that emits visible light in response to ionizing radiation. In watch dial paint, zinc sulfide actsas the scintillator. Radium present in the radium salts decomposes spontaneously, emitting alpha particles. Theseparticles can cause damage to the body when they enter human tissue. Alpha particles are especiallyharmful to the blood, liver, lungs, and spleen because they can alter genetic information in the cells.Radium can be deposited in the bones because it substitutes for calcium.

Based on Reference Table F, describe the solubility of zinc sulfide in water.

5. Base your answer to the following question on the Reference Tables for Physical Setting/Chemistry.

a Complete the data table provided for the followingGroup 18 elements: He, Ne, Ar, Kr, Xeb Using information from your data table in part a,construct a line graph on the grid provided, following thedirections below.• Mark an appropriate scale on the axis labeled "FirstIonization Energy (kJ/mol). "• Plot the data from your data table. Circle each pointand connect the points.c Based on your graph in part c, describe the trend infirst ionization energy of Group 18 elements as theatomic number increases.

6. Base your answer to the following question on the information below and on your knowledge of chemistry.

When magnesium is ignited in air, the magnesium reacts with oxygen and nitrogen. The reaction betweenmagnesium and nitrogen is represented by the unbalanced equation below:

Mg(s) + N2(g) Mg3N2(s)Explain, in terms of electrons, why an atom of the metal in this reaction forms an ion that has a smallerradius than its atom.

7. In the 19th century, Dmitri Mendeleev predicted theexistence of a then unknown element X with a mass of68. He also predicted that an oxide of X would have theformula X 2O3. On the modern Periodic Table, what isthe group number and period number of element X?


The atomic number and corresponding atomic radius of the Period 3 elements are shown in the data tablebelow.

Explain, in terms of electrons, the change in radius when a sodium atom becomes a sodium ion.


The balanced equation below represents the reaction of glucose, , with oxygen at 298 K and101.3 kPa.

Compare the entropy of the reactants to the entropy of the products.

10. In a laboratory experiment, a student determined the mass of the product, NH4Cl(s), to be 0.372 grams.

a Calculate the gram formula mass of NH4Cl(s). Round atomic masses from the Periodic Table to thenearest tenth. [ Show all work. Indicate the correct answer in proper significant figures and include anappropriate unit.]

b Calculate the number of moles of NH4Cl(s) produced. [Show all work. Indicate the correct answer inproper significant figures.]

11. Acid rain is a problem in industrialized countries around the world. Oxides of sulfur and nitrogenare formed when various fuels are burned. These oxides dissolve in atmospheric water droplets that fallto earth as acid rain or acid snow. While normal rain has a pH between 5.0 and 6.0 due to the presence of dissolved carbon dioxide,acid rain often has a pH of 4.0 or lower. This level of acidity can damage trees and plants, leachminerals from the soil, and cause the death of aquatic animals and plants. If the pH of the soil is too low, then quicklime, CaO, can be added to the soil to increase the pH.Quicklime produces calcium hydroxide when it dissolves in water.

Balance the neutralization equation below, using the smallest whole number coefficients.

12. Base your answer to the following question on theinformation below.

The catalytic converter in an automobile changesharmful gases produced during fuel combustion to lessharmful exhaust gases. In the catalytic converter,nitrogen dioxide reacts with carbon monoxide toproduce nitrogen and carbon dioxide. In addition, somecarbon monoxide reacts with oxygen, producing carbondioxide in the converter. These reactionsare represented by the balanced equations below.

Reaction 1: 2NO2(g) + 4CO(g) N2(g) + 4CO2(g) +1198.4 kJReaction 2: 2CO(g) + O2(g) 2CO2(g) + 566.0 kJDetermine the oxidation number of carbon in each carbon compound in reaction 2.Your response must include both the sign and value of each oxidation number.


John Dalton, an early scientist, sketched the structure of compounds using his own symbols for theelements known at the time. Dalton's symbols for four elements and his drawing of potassiumaluminum sulfate are represented by the diagram below.

Today, it is known that the chemical formula for potassium aluminum sulfate is . It is a hydrated compound because water molecules are included within its

crystal structure. There are 12 moles of H2O for every 1 mole of . The compound containstwo different positive ions. The gram-formula mass of is 474 grams per mole.

Show a numerical setup for calculating the percent composition by mass of water in .

14. Base your answer to the following question on Draw a correct Lewis electron-dot structure for each of thefollowing.a An atom of hydrogenb An atom of nitrogenc A molecule of ammonia (NH3)


Bond energy is the amount of energy required to break a chemical bond. The table below gives aformula and the carbon-nitrogen bond energy for selected nitrogen compounds.

Explain, in terms of charge distribution, why a molecule of hydrogen cyanide is polar.


A 1.00-mole sample of glucose, , completely reacts with oxygen, as representedby the balanced equation below.

Using the axes above, complete the potential energy curve for the reaction of glucose with oxygen.


Heat is added to a 200.-gram sample of H2O(s) to melt the sample at 0°C. Then the resulting H2O( ) isheated to a final temperature of 65°C.

Determine the total amount of heat required to completely melt the sample.


On the grid below, mark an appropriate scale on theaxis labeled "Boiling Point (K)."

19. An aqueous solution contains 300. parts per million of KOH. Determine the number of grams of KOHpresent in 1000. grams of this solution.

20. A sample of water is heated from a liquid at 40°C to a gas at 110°C. The graph of the heating curve isshown below.

a. On the heating curve diagram provided below, label each of the following regions:

Liquid, onlyGas, onlyPhase change

b. For section QR of the graph, state what is happening to the water molecules as heat is added.

c. For section RS of the graph, state what is happening to the water molecules as heat is added.


Given the heating curve where substance X starts as a solid below its melting point and is heateduniformly:

Identify a line segment in which the average kinetic energy is increasing.


A student is instructed to make liter of a aqueous solution of .

In order to prepare the described solution in thelaboratory, two quantities must be measured accurately.One of these quantities is the volume of the solution.What other quantity must be measured to prepare thissolution?


The equilibrium equation below is related to the manufacture of a bleaching solution.In this equation, means that chloride ions are surrounded by water molecules.

Use the key to draw two water molecules in the box, showing the correct orientation of each watermolecule toward the chloride ion.

24. A potential energy diagram for a chemical reaction is shown below. On this diagram, draw a curve to showhow the potential energy diagram will change when a catalyst is added to the reaction.


The compounds and are soluble in water.Explain why the total thermal energy of a sample containing 22.2 grams of dissolved in 200.grams of water at 20.°C is greater than the total thermal energy of a sample containing 11.1 grams of

dissolved in 100. grams of water at 20.°C.


Given the equilibrium equation at 298 K:

KNO3(s) + 34.89 kJ K+(aq) + NO3–(aq)Describe, in terms of LeChatelier's principle, why anincrease in temperature increases the solubility of KNO3.


The diagram and balanced ionic equation below represent a voltaic cell with copper andsilver electrodes and the reaction that occurs when the cell is operating.

Describe the direction of electron flow in the external circuit in this operating cell.


A student constructs an electrochemical cell during a laboratory investigation. When the switch isclosed, electrons flow through the external circuit. The diagram and equation below represent this celland the reaction that occurs.

Write a balanced half-reaction equation for the oxidation that occurs when the switch is closed.


Electroplating is an electrolytic process used to coatmetal objects with a more expensive and lessreactive metal. The diagram below shows anelectroplating cell that includes a battery connectedto a silver bar and a metal spoon. The bar and spoonare submerged in AgNO3(aq).

Explain why AgNO3 is a better choice than AgCl foruse in this electrolytic process.


The diagram below represents an operating electrolytic cell used to plate silver onto anickel key. As the cell operates, oxidation occurs at the silver electrode and the mass of thesilver electrode decreases.

Explain, in terms of Ag atoms and Ag+(aq) ions, why the mass of the silver electrode decreases as the celloperates.


Indigestion may be caused by excess stomach acid (hydrochloric acid). Some products used to treatindigestion contain magnesium hydroxide. The magnesium hydroxide neutralizes some of the stomachacid. The amount of acid that can be neutralized by three different brands of antacids is shown in thedata table below.

Based on Reference Table F, describe the solubility of magnesium hydroxide in water.


A student makes an aqueous solution of lactic acid. A formula for one form of lactic acid is shownbelow.

The solution is placed in a sealed flask to be used in a laboratory investigation. The equation belowrepresents the lactic acid equilibrium system in the flask

Identify one organic functional group in a molecule of lactic acid.


In a titration experiment, a student uses a 1.4 M HBr(aq) solution and the indicator phenolphthaleinto determine the concentration of a KOH(aq) solution. The data for trial 1 is recorded in the tablebelow.

In the space below show a correct numerical setup for calculating the molarity of the KOH(aq) solution fortrial 1.

______________________________


In performing a titration, a student adds three drops of phenolphthalein to a flask containing 25.00milliliters of HCl(aq). Using a buret, the student slowly adds 0.150 M NaOH(aq) to tile flask until onedrop causes the indicator to turn light pink. The student determines that a total volume of 20.20milliliters of NaOH(aq) was used in this titration.

The concentration of the NaOH(aq) used in the titration is expressed to what number of significant figures?


Using burets, a student titrated a sodiumhydroxide solution of unknown concentration with astandard solution of 0.10 M hydrochloric acid. Thedata are recorded in the table below.

Determine both the total volume of HCl(aq) and thetotal volume of NaOH(aq) used in the titration.

36. Base your answer to the following question on the information below, which relates the numbers of neutrons and protons for specific nuclides of C, N,Ne, and S.

Explain, in terms of atomic particles, why S-32 is a stable nuclide.

37. Base your answers to the following questions on the information below.

Uranium-238, a solid, is a naturally radioactive element found in the earth's crust. As it decays one of theproducts is radon-222 which is a gas and is very radioactive.

a Write the equation for the decay of Rn -222.

b The half-life of Radon-222 is 3.82 days. How many grams of a 1.0 gram sample of Rn -222 wouldremain after 7.64 days?


Nuclear fission has been used to produce electricity. However, nuclear fusion for electricityproduction is still under development. The notations of some nuclides used in nuclear reactions areshown in the table below.

Complete the nuclear equation belowfor the fission of by writing the notation of the missing product.


A student performed an experiment to determine the total amount of energy stored in a peanut. Theaccepted value for the energy content of a peanut is 30.2 kilojoules per gram. The student measured 100.0grams of water into a metal can and placed the can on a ring stand, as shown in the diagram below. Thepeanut was attached to a wire suspended under the can.The initial temperature of the water was recorded as 22.0° C. The peanut was ignited and allowed to burn.When the peanut finished burning, the final water temperature was recorded as 57.0° C. The student'sexperimental value for the energy content of this peanut was 25.9 kilojoules per gram.

Calculate the total amount of heat absorbed by the water. Your response must include both a correctnumerical setup and the calculated result.


A student, wearing chemical safety goggles and a labapron, is to perform a laboratory test to determine thepH value of two different solutions. The student isgiven one bottle containing a solution with a pH of 2.0and another bottle containing a solution with a pH of5.0. The student is also given six dropping bottles, eachcontaining a different indicator listed in ReferenceTable M.State one safety precaution, not mentioned in thepassage, that the student should take while performingtests on the samples from the bottles.

Answer KeyConstructed Response

1.

2. 153.

4. Examples: –Zincsulfide is not solublein water. –insoluble

5.

6. – An atom ofmagnesium loses itsouter shell electronsto form the Mg2+ ion.– The electronconfiguration of amagnesium atom is2-8-2, and theelectron configurationof the magnesium ionis 2-8. – An atom ofthe metal loseselectrons to form theion.

7. Group 13 and Period4

8. –The radius of asodium ion is smallerbecause the sodiumatom lost oneelectron. –An Na+ ionis smaller because ithas one fewerelectron shell.

9. –The entropy of thereactants is less thanthe entropy of theproducts. –Thereactants are moreordered. –Theproducts have greaterentropy.

10. a) 14.0 + 4(1.0) +35.5 = 53.5 g b)0.372g x 1.00mole/53.5g = .00695mole

11. 2 HNO3 + 1 Ca(OH)2 1 Ca(NO3)2 + 2 H2

O12. +2 for carbon in CO,

+4 for carbon in CO2

13.14.

15. Examples: Themolecule has anasymmetrical chargedistribution.; Themolecule has anunequal distributionof charge.

16.

17. 66800 J or 6.68 × 104

J

18. Allow 1 credit formarking anappropriate scale.

19. 0.300 g20.

b. Examples: –Thewater moleculesacquire more kineticenergy. –Heat isconverted to kineticenergy of the watermolecules. –Thewater moleculesspeed up or increasetheir relative motion.c. Examples: –Thepotential energy ofthe water moleculesincreases. –The watermolecules changefrom the liquid phaseto the gas phase.–There is lessattraction between theH2O molecules.

21. Examples: or or

22. Examples: – mass ofCa(NO3)2 – mass ofsolute – mass

23.

24.

25. – Both samples are at20. C, but the largersample has morematter. – The largersample has twice asmany particles. – Thetotal thermal energy isdirectly proportionalto the masses of thesamples

26. Increasing thetemperature favors theforward, endothermicreaction or Addingheat shifts thereaction to the right

27. Acceptable responsesinclude, but are notlimited to: • Electronsflow from the copperelectrode to the silverelectrode through thewires and voltmeter.• The e- flow is fromCu to Ag in theexternal circuit fromanode to cathode

28. Al ® 3e– +Al3+ 2Al ® 2Al3+ + 6e–

29. Examples: – Silvernitrate produces moreions than silverchloride in water. – AgNO3 readilydissolves in H2O;AgCl dissolves onlyslightly in H2O.

Answer KeyConstructed Response

30. Silver atomslose electrons andbecome silver ions inthe solution. Some of the Ag atomsbecome Ag+ ions. Silver atomsare oxidized to silverions.

31. insoluble or notsoluble

32.

33. ((1.4)(15.40))/(22.10)• (1.4)(15.40) = X(22.10)(1.4M)(15.40mL) =MB(22.10mL)

34. 3; Three35. Examples: – 9.50 ml

HCl(aq) and 3.80 mLNaOH(aq) – 9.5 mLHCl(aq) and 3.8 mLNaOH(aq)

36. The neutron-to-protonratio causes thenuclide to be stable.

37. a) 22286Rn 21884Po+ 42He b) 0.25 grams

38. 10n39.40. Acceptable responses

include, but are notlimited to: • Wearprotective gloves. •Avoid spills.Note: Do not allowcredit for “wearinggoggles” or “wearingan apron.”

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