Homework answers / question archive / Final Project Spring 2021 The elements follow the periodic trends in Chemistry Name Elemental Symbol Atomic Number Lt 119 Dunium Dm Vibranium Woodicon Atomic mass (g/mol) Group Solubility Specific heat J/gC 304

Final Project Spring 2021 The elements follow the periodic trends in Chemistry Name Elemental Symbol Atomic Number Lt 119 Dunium Dm Vibranium Woodicon Atomic mass (g/mol) Group Solubility Specific heat J/gC 304

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Final Project Spring 2021 The elements follow the periodic trends in Chemistry Name Elemental Symbol Atomic Number Lt 119 Dunium Dm Vibranium Woodicon Atomic mass (g/mol) Group Solubility Specific heat J/gC 304.64 1 See Solubility Table Lt2O = 7.88 120 307.2 2 0.447 Vb 163 417.28 13 13.32 Wd 164 419.84 14 0.809 Basiline Bl 165 420.79 15 3.86 Chanium Ch 166 424.96 16 2.74 Jasmine Ja 167 437.22 17 6.98 Lit Constants: R = 0.0821 L - atm/mol K R = 8.314 J/mol-K R = 1.987 kcal/mol-K R = 8.314 kg m2/sec2 mol-K Specific Heat H2O = 4.184J/gC Specific Heat Lt2O = 7.88 J/gC Plank’s Constant = 6.62607015 × 10−34 J*sec Solubility rules, note our new elements follow this table, adapted from Table 7.2 Soluble Ionic Compounds Always Soluble Exceptions NH4+, Group I cations None Insoluble compounds Cl-, Br-, I-, Ja- Compounds with Ag+, Hg2+, Pb2+, Wd2+ Acetate, bicarbonate, nitrate, chlorate None Sulfate (SO4 2- Compounds with Ag+, Ba2+, Ca2+, Hg2+, Pb2+, Dm2+, Wd2+ Contains these ions Exceptions Carbonate, chromate, Compounds with phosphate, sulfide group 1 cations and NH4+ Hydroxide Compounds with group 1 cations, Ba2+, Dm2+ 1. (10 points) Energy Questions Students in chemlab on Tatooine developed a method to sterilize Li-water (Lt2O) by bombarding it with light with a frequency of 1 x 10-6 Hz. a) What wavelength of light does this correspond to ? [ PUT ANSWER AND WORK HERE] b) How much energy is required to generate light with this wavelength. [ PUT ANSWER AND WORK HERE] c) Would this light be harmful to humans ? What would this wavelength be useful for ? [ PUT ANSWER/ DISCUSSION HERE] 2. (15 points) In another experiment students wanted to use light to heat water. a) (2points) Determine the Joules of energy required to raise the temperature of 405.0 g of water from 26.5 °C to 36.5 °C? [ PUT ANSWER HERE] b) (5 points) Show work and explain in words the process you used to find your answer [ PUT Explanation AND WORK HERE] c) (2 points) Determine moles of photons required to raise the temperature of the water, if the light has a wavelength of 180nm ? [ PUT ANSWER HERE] d) (4 points) Show all work. [ PUT ANSWER AND WORK HERE] e) (2 points) List two learning goals that are addressed in the problem LEARNING GOAL #1 _______________________________________ LEARNING GOAL #2 _______________________________________ 3. (10 points) The scientists on Tatooine made Lt2O by first breaking apart Lt 2 by using a laser focused into the reaction vessel. a. (1 point) If the bond dissociation energy for Lt-Lt bond is 436 kJ/mol, what is the energy (in units of Joules) required to break a single Lt-Lt bond in a molecule of Lt2 gas? [ PUT ANSWER HERE] b. (3 points) Explain your process and show all work. [ PUT ANSWER AND WORK HERE] c. (5 points) What laser wavelength (in units of nm) should Shuri’s undergrads use to break the single hydrogen-hydrogen bond in part a? (Show all work) [ PUT ANSWER AND WORK HERE] d. (1 point) List one Learning Goal addressed in this problem. 4. (15 points) Write the electron configuration (starting from the nearest noble gas) of the following elements/ ions (2 points each) a) K ______________________________________________ b) Ca+ _____________________________________________ c) Br _____________________________________________ d) Lt+ ______________________________________________ e) (4 points) Use the electron configuration above to explain the trends in atomic radius that you expect to observe. [ PUT ANSWER AND WORK HERE] 5. (10 points) Lewis Structures Here are three hypothetical elements, X, Y, and Z. Element X has 5 valence electrons, element Y has 6 valence electrons, and element Z has 7 valence electrons. a) (4points) Use Lewis structures and formal charges to determine the most likely structure for the compound formed by these three elements ? [ PUT LEWIS STRUCTURE AND WORK HERE] b) (4 points) Explain your process and show all your work and reasoning. c) (1 point) List a Learning Goal addressed by this problem. d) (1 point) List one question in the text similar to this problem. 6. (10 points) Use the MO diagram given to answer the following questions regarding the molecule Ja2 A) ( 2points) Label and fill in the following diagram for Wd2 and use it to answer the following questions. b) (2 points) What is the HOMO for this molecule ? ___________________ c) (2 points) What is the LUMO for this molecule ? __________________ d) (2 points) What is the bond order ? ___________________ Show work: e) (2 points) Can this molecule exist ? Explain your answer using the calculations above. 7. (10 points) Dilution & Solutions A student needs to make a solution for their lab experiment . The only available stock solution is 1.8M VbCl3 a) (1 point) How many grams of VbCl3 should they add to 1.5 L of water to make a solution that is 0.85M ? _______________ b) (3 points) Show work [ PUT ANSWER AND WORK HERE] c) (1 point) If the student accidentally adds 2225 grams of VbCl3 into 2.2L of water instead, what would the concentration be ? [ PUT ANSWER AND WORK HERE] d) (5 points) Is the solution ruined or can they fix their error ? Explain how they can fix their error and what should they add to make the solution 0.85M again ? (Show numbers and work and explain your reasoning.) 8 (10 points) Ionic Equations a. (4 points) Write the molecular , ionic and net ionic equations for the reaction between sulfuric acid and Litium hydroxide. [ PUT ANSWER AND WORK HERE] b. (3 points) If 200 ml of the 0.789M sulfuric acid is required to neutralize 100ml the Litium hydroxide what is the molarity of the base ? [ PUT ANSWER AND WORK HERE] c. (3 points) students make two observations during the titration. The solution was initially bright pink but turned colorless at the titration endpoint. Additionally, the solution became cloudy with the addition of sulfuric acid. Explain why the solution becomes colorless AND cloudy. [ PUT ANSWER AND WORK HERE] 9. (15 points) Oxidation/Reduction Reactions a) (2 each) Write the oxidation numbers for all the elements in the following compounds: H2SO4 - Lt2O - DnCl2 - Cl2 - Lt2 b) (2 points) Write the half reaction for the oxidation of Fe (s). c) (3 points) Write the half reaction for the reduction of Ag+ 10. Calorimetry (10 points) A sample of an unknown substance fromTatooine has a mass of 0.02398 kg. The substance is heated to 473 K and then quickly transferred into 500.0mL of Lt2O initially at 23.9 °C (density = 0.887 g/mL ) in a bomb calorimeter (C=893 J/°C). When the heat transfer process has completed, the final temperature is 30.5°C. Use the information provided and the table of specific heats of Tatooine substances on the first page of this file to answer the questions below a) (1 point) Determine the specific heat capacity of the substance. b) (6 points) Show your work and paste an image of your work in the box. [ PUT ANSWER AND WORK HERE] c) (1 point) Which substance from Tatooine do you think this is ? d) (2 points) Which substance would have the most heat absorbing property ? Why ? [ PUT ANSWER HERE] 11. Stoichiometry (10 points) How many grams of O? would be required to generate 5.876kg of BlO? in the unbalanced reaction below assuming the reaction has only 85.0% yield? BlO (g) + O? (g) → BlO? (g) a) (2 points) Grams of O2 required ? [ PUT ANSWER HERE] b) (8 points) Show work and explanation [ PUT ANSWER AND WORK HERE] 12. Stoichiometry / Gas Laws (15 points) Hydrogen storage has the potential to be the next generation of energy storage materials that can be used in hydrogen fuel cells and produce zero greenhouse gases. Researchers on Tatooine have shown that vibranium can store hydrogen gas as vibranium hydride. a. (2 points) Balance this reaction: Vb(s) + H2(g) → VbH3(s) b. (2 points) If we charge (fill) a reaction vessel with hydrogen gas and vibranium at 210 °C,what will happen to pressure as the reaction proceeds towards completion ? Explain your answer. [ PUT ANSWER AND WORK HERE] c. (2 points) If we react 124.0 g of Vibranium (atomic weight 417.28 g/mol) with 18.8 atm of hydrogen gas (200 °C, 1.24 L vessel), how many grams of VbH3(s) will be produced? [ PUT NUMBER ] d. (7 points) Show all work and explain your process [ PUT ANSWER AND WORK HERE] e. (2 points) What will the pressure in the vessel be after the reaction has gone to completion? [ PUT ANSWER AND WORK HERE] 13. (10 points) Thermodynamics and Properties of Gases Given the following sets of equations determine the ΔH for the reaction. (Not all equations will be used) 2BlO2 (g) - > BlO + O2 2BlH3(g) ---> Bl2(g) + 3H2(g) 1 ⁄2Bl2(g) + 2H2O(?) ---> BlO2(g) + 2H2(g) BlO (g) + O3 -> BlO2 (g) + O2 (g) O3 (g) -> 3/2 O2 (g) O2 (g) -> 2O (g) Bl2 (g) -> 2Bl (g) ΔH° = +192 kJ ΔH° = +170 kJ ΔH° = -198.9 kJ ΔH° = +42.3 kJ ΔH° = +495.0 kJ ΔH° = +170 kJ a) (1 point) Determine the ΔH of the reaction. [ PUT ANSWER HERE] b) (6 points) Show your work and explain your process here [ PUT ANSWER AND WORK HERE] c) (2 points) Explain why this approach is a valid way to determine the ΔH° d) (1 point) Find a similar example in the text. 14. (10points) Based on the bond energies for the reaction below, what is the enthalpy of the reaction, in kJ (2 points) ? Show all work (8 points) H?(g) + N?(g) + 2 C(g) → 2 HCN(g) Bonus ? Students on Tatooine are studying thermochemistry for food-storage applications. What kind of reaction (exothermic or endothermic) would you want to keep food cold? Explain your answer.

Link to textbook: https://openstax.org/details/books/chemistry-atoms...

Tips:

-For questions talking about learning goals you must be very specific. *put in own words*

Example: learning goal for a Bohr Model question-

The learning goal for this question is (look at textbook chapter 3.2) to describe the Bohr model of a hydrogen atom, and use the Rydberg equation to calculate the energies either admitted or absorbed by the atoms.

-If the next question is asking for examples, look through the chapter and find an example displaying the topic of the learning objective.

Example: textbook example for a Bohr Model question-

An example from the textbook would be (look in textbook chapter 3.2) example 3.5

-OR IF YOU LOOK AT EXERCISES

An example from the textbook would be (look at exercises in the textbook) example #16 in the 3.2 The Bohr Model section