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Description Unit V Problem Solving In the ionic compounds LiF, NaCl, KBr, and RbI, the measured cation–anion distances are 2.01 Å (Li–F), 2.82 Å (Na-Cl), 3.30 Å (K–Br), and 3.67 Å (Rb–I), respectively. 1. Predict the cation-anion distance of each ionic compound above using the values of ionic radii given in Figure 7.7 on page 257 in the textbook. To receive full credit, you must show how you predicted the distance for each CHM 1030, General Chemistry I 3 molecule by providing a step-by-step solution for each molecule. The solution for each molecule is worth 8 points; thus, a total of 32 total points is possible for this question. 2. Calculate the difference between the experimentally measured ion-ion distances provided at the beginning of this assignment and the ones you have predicted in problem 1. You must show how you calculated the difference for each molecule by providing a step-by-step solution for each molecule to get full credit (6 points for each molecule; total possible points for this section is 24 points). Assuming that we have an accuracy of 0.04Å in the measurement, please indicate for each molecule if your predicted ion-ion distances are accurate or not accurate with respect to their experimental ion-ion distances (2 points for each molecule; total possible points for this section is 12 points). A total of 32 total points is possible for this question. 3. What estimates of the cation-anion distance would you obtain for these four compounds using their bonding atomic radii? (Note: these values are also in Figure 7.7 but are different from the ionic radii.) For each of the four compounds, calculate the difference between the predicted ionic bond distance, which you calculated in problem 1, and predicted atomic bond distances you calculated in this problem. To receive full credit, you must show how you calculated the difference for each molecule by providing a step-by step solution for each molecule (6 points for each molecule; total possible points for this section is 24 points). Again, assuming that we have an accuracy of 0.04Å in the measurement, indicate for each molecule if your predictions are less or more accurate using the atomic radii prediction method; explain your answer (2 points for each molecule; total points possible for this section is 8 points). Using your knowledge of atomic and ionic radii trends in the periodic table, why might one prediction method be more appropriate to use than the other in certain molecules (worth 4 points)? A total of 36 points is possible for this set of questions.

Description Graded Assignment Lab Report Question:  How do different metals act in solution and react with other compounds? Hypothesis:  Use your knowledge of the periodic table to write a hypothesis that describes how a transition metal might behave differently from a nontransition metal. Write your hypothesis as an if-then statement. (2 points) Procedure 1. Place 10 drops of KNO3 in wells 1A, 1B, and 1C of microplate 1, as shown in the table below. Place 10 drops of Ca(NO3)2  in wells 2A, 2B, and 2C. 2. Continue this pattern of placing 10 drops in three wells for each of the compounds listed in the table. 3. Add 10 drops of NH4OH to each well in row A of each microplate. In each case, mix thoroughly with stirring rod. 4. Add 10 drops of HCl to each well in row B. In each case, mix thoroughly with a stirring rod. 5 .Continue this pattern of placing 10 drops in the wells as shown in the table. Do not add anything to the control wells. 6. Observe the controls. Record your descriptions of the controls. 7.  Observe rows A and B on each microplate with a hand lens. Record any variations from the control, if no reaction record NR Table 1  Observations After Mixing the Reactants for Microplate 1 1 Metal is K KNO3  10 drops 2 Metal is Ca Ca(NO3)2  10 drops 3 Metal is V NH4VO3  10 drops 4 Metal is Mn MnSO4  10 drops A  (NH4OH) 10 drops B  (HCl) 10 drops C  (Control) KNO3 Ca(NO3)2 NH4VO3 MnSO4 5 points Table 2 Observations After Mixing the Reactants for Microplate 2 1 Metal is Fe Fe(NO3)3 2 Metal is Co Co(NO3)2 3 Metal is Cu Cu(NO3)2 4 Metal is Zn Zn(NO3)2 A  (NH4OH) 10 drops B  (HCl) 10 drops C (Control) Fe(NO3)3 Co(NO3)2 Cu(NO3)2 Zn(NO3)2 5 points Answer the questions below. When you have finished, submit this assignment to your teacher by the due date for full credit. (2 points) Score 1.  Which combinations of substances resulted in a chemical change? Answer: (2 points) Score 2.  For each metal that participated in a chemical change, write the type of metal it is, based on your examination of the periodic table. Answer:  Transition:  Nontransition: (2 points) Score 3.  Were there any metallic compounds that did not react with either the acid or the base? Write the type of metal, based on your examination of the periodic table. Answer:  Transition: Nontransition: (2 points) Score 4.  Make a general statement about the reactivity of the metals in this experiment. Answer: (Hint…which were more reactive, transition or nontransition) Your Score ___ of 20

Description EXP#8: Heats of Reaction – Hess’ Law On http://chemcollective.org/ (Thermochemistry --> Hess LAw) In this experiment you will determine and compare the quantity of heat energy released in three exothermic chemical reactions. This activity provides a demonstration of Hess' Law using three reactions: the solubility NaOH in water, the solubility NaOH in HCl and the reaction of a solution of HCl and a solution of NaOH. Reaction 1: Solid sodium hydroxide dissolves in water to form an aqueous solution of ions. NaOH(s) ? Na+(aq) + OH-(aq) + x1 kJ Reaction 2: Solid sodium hydroxide reacts with an aqueous solution of hydrogen chloride to form water and an aqueous solution of sodium chloride. NaOH(s) + H+(aq) + Cl-(aq) ? H2O(l) + Na+(aq) + Cl-(aq) + x2 kJ Reaction 3: An aqueous solution of sodium hydroxide reacts with an aqueous solution of hydrogen chloride to form water and an aqueous solution of sodium chloride. Na+(aq) + OH-(aq) + H+(aq) + Cl-(aq) ? H2O(l) + Na+(aq) + Cl-(aq) + x3 kJ In order to accurately measure the heat released in each reaction, we will be using a calorimeter. (For this experiment a styrofoam cup will act as the calorimeter). The change in temperature that occurs for each reaction will be used to calculate the energy released in kilojoules per mole of sodium hydroxide used. We can assume for our calculations that any heat transferred to the styrofoam and surrounding air will be negligible. We can also assume that the specific heat of water is 4.18 J/g°C. PROCEDURE Reaction 1 In the glassware menu, take out a 50 ml graduated cylinder and a foam cup. From the instruments menu, take out the scale. From the chemical stockroom, move the distilled water and solid NaOH on to the workbench. Transfer 50.0 ml of water to the foam cup. To do this, drag the carboy of water on to the graduated cylinder. (Before you release the mouse button, the cylinder will turn blue to indicate that it is the recipient). A transfer textbar will activate at the bottom of the screen, enter "50.0" (ml) and click on pour. (You will notice that the graduated cylinder reads 50.0ml.) Weigh about 1 gram of solid sodium hydroxide pellets, NaOH(s), directly into the foam cup and record its mass to the nearest 0.01 gram. To do this place the foam cup on the balance so it registers a mass, then click the "Tare" button. Drag the NaOH bottle onto the foam cup. (When you release the mouse, the bottle will be tipped to show that it is in pour mode). Next, type "1.00" (grams) into the transfer bar and then click pour. Note that the balance now reads the mass of the transferred NaOH. You may now take the cup off of the scale and remove the scale from the workbench. Click on the graduated cylinder, record its temperature and then drag it onto the foam cup. (When you release the mouse, the graduated cylinder will be tipped to show that it is in pour mode.) Enter "50.0" in the transfer bar and then click pour. Record the highest temperature. Reaction 2 Take the 0.5M HCl from the strong acids cabinet and a foam cup and 50 ml graduated cylinder from the glassware menu and place them on the workbench. The procedure for Reaction 2 is the same as for Reaction 1 except that 50.0 ml of 0.50 M hydrochloric acid solution is used in place of the water. After measuring 50.0 ml of the HCl solution into the graduated cylinder, proceed as before with steps c through d of the procedure. Reaction 3 Take out another graduated cylinder, a fresh foam cup, the 1.0 M HCl and the 1.0 M NaOH. (If you are running out of room, you may remove the previous chemicals.) Measure 25.0 ml of 1.0 M hydrochloric acid solution into the foam cup. Pour an equal volume of 1.0 M sodium hydroxide solution in the clean graduated cylinder. Record the temperature of each solution to the nearest 0.1°C. Pour the sodium hydroxide solution into the foam cup and record the highest temperature obtained during the reaction. PROCESSING THE DATA You make your own repot sheet for this experiment. Prepare a table with the following headings: Reaction, Mass of NaOH, Initial Temperature, Final Temperature, Heat Energy Released, Moles of NaOH and Molar Heat of Reaction. Next, create a row for each reaction. Complete the table using your collected information and any needed calculations. Write the net ionic equations for Reactions 1, 2 and 3. Consider the heat given off in your reactions; add variables to your equations to represent heat evolved in kJ/mole. Use x1 for Reaction 1, x2 for Reaction 2, and x3 for Reaction 3 (as written above). The energy, x1, in Reaction 1 represents the energy of solution for one mole of NaOH(s). Look at the net ionic equations for Reactions 2 and 3, and make a similar statement concerning the significance of x2 and x3. Find the difference between the value of x2 and the sum of x1 plus x3. Account for any similarity or difference. Calculate the percent difference between x2 and the sum of x1 and x3. (Assume x2 to be correct.) Suppose you had used 4.00 grams of NaOH(s) in Reaction 1. What would have been the number of Joules released in the reaction? What effect would this have on the value of x1? DISCUSSION Provide an explanation of the results collected above. Look up Hess' Law and discuss how this experiment is an illustration.

Description The stockroom of the virtual laboratory contains a cabinet called “Thermochemistry Solutions.” Different concentrations of Reagent A and Reagent B have been placed into this cabinet. You will use these solutions to answer the questions below. 1) (3 pts) Use the lab to measure Delta Ho for the reaction that occurs when reagents A and B are combined: A + B ==> C Please note that each prepared flask contains 100 mL of solution. Also, you may assume the heat capacity of the aqueous solutions is equal to the heat capacity of water 4.18 J/g Ko Please describe your complete procedure and the key quantities you measure. Points are based upon your final answer and whether or not you explain your procedure in sufficient detail for us to reproduce your actions. You are not graded on the method you used: all approaches that meet the above goal are equally valid. 2) (3pts) Using water and the reagents provided in the lab, create two solutions such that when you mix equal amounts together, the resulting solution has an initial temperature of 50o C. Please describe your complete procedure and the key quantities you measured. Points are based upon your final answer and whether or not you explain your procedure in sufficient detail for us to reproduce your actions. You are not graded on the method you used: all approaches that meet the above goal are equally valid. http://chemcollective.org/vlab/90

Description ALL LABS REQUIRE A COMPLETE AND PROPERLY FORMATTED LAB REPORT A lab format example you can use is in the link below: http://www.intervisualtechnology.us/data/1/22383/Lab_report_outline.pdf - I need all the virtual lab questions answered in complete sentences. - I need the work done in a lab format which there is an example in the link above. Remember that the lab format i attached is an example. I need the Question, Hypothesis, Procedure, Results and the analysis and conclusion for this actual lab. - Some of the questions that i need answered are in the lab under the "problem description" tab. The link below is the actual lab that you'll need in order to complete this assignment. http://chemcollective.org/vlab/90

Description a.9876 meters to miles (1609.3 meters = 1 mile)

Description Organic chemistry 2, interpret significant peaks given IR spectroscopy and make table. Then, comment as to if the IR corresponds to 3,5-Dimethylisoxazole.  

Description Data Analysis For the standards, use Beer's Law and Excel to convert %T to absorbance. The standards should be presented in properly labeled figures (see the syllabus) with absorbance on the Y axis and wavenumbers on the X axis. Spectra for shoe samples must say what shoe is being shown in the figure caption, and will have %T on the Y axis. Infrared spectra must be included for the standards and unknowns with the major bands identified. Annotations can be done with pen, rather than digitally, as long as they're legible. Discussion For this laboratory, the following must be included in the discussion: Which band(s) in the IR spectrum did you use to determine the ethylene content of the co-polymer? Which band(s) did you use to determine the vinyl acetate content? To which functional groups and vibrational modes do these bands correspond? 2. For the standards, how do the absorbance intensities change as the composition changes? Are these changes consistent with compositional changes? Explain 3. Is it possible to distinguish between the three insoles with only ATR-IR? 4. Is this technique suitable for routine forensic analysis of copolymer samples? Justify your answer. References Laboratory adapted from: K.R. Williams, "Analysis of ethylene-vinyl acetate copolymers: a combined TGA/FTIR experiment," J. Chem. Ed. 1994, 71, A195. Report Checklist -Header -Abstract - What are you trying to find? How are you finding it? What are your main results? -Methods - You can say "We followed the lab handout." and leave it at that if that's all you did. If you made any changes or did things differently, that needs to be described. Do not just rewrite the handout; that's a waste of time and I'm not reading that. -Data Analysis: -Three standard spectra: AT1231, AT1821A, and SA340502 Y axis converted to absorbance, wavenumbers on X axis  -Caption or legend -Annotations of absorption features -Proper range with flipped x axis -Three shoe spectra -% Transmittance on Y axis, wavenumbers on X axis Caption or legend -Annotations of absorption features -Proper range with flipped x axis - see Figure 5, below -Discussion: Must be in complete sentences and not just answering the question (i.e. don't say "I's 55+5 mg", say "We determined that there was 55+5 mg of iron in the fresh tablet sample") Polythylene wavenumbers, functional groups, vibrational modes Polyvinyl acetate wavenumbers, functional groups, vibrational modes Standards: absorbance changes with composition Distinguishing insoles Suitability 

Description For the graphs provided, I need an analysis. These graphs are from a lab where we tested 3 shoes to determine the Co-Polymer Composition (ethylene vinylacetate) (EVA). The SAMPLES we tested are the graphs labeled “Hello Kitty”, “Toy Story”, and “Pink New Balance”  The STANDARDS are labeled “AT1231”, “AT1821” and “SA340502” Standard 1 (AT1231): Nominal wt% vinyl acetate- 12% Standard 2 (AT1821): Nominal wt% vinyl acetate- 18% Standard 3 (SA340502): Nominal wt% vinyl acetate- 40% Questions to answer:  ???Which band(s) in the IR spectrum did you use to determine the ethylene content of the co-polymer? Which band(s) did you use to determine the vinyl acetate content? To which functional groups and vibrational modes do these bands correspond? ???For the standards, how do the absorbance intensities change as the composition changes? Are these changes consistent with compositional changes? Explain ???Is it possible to distinguish between the three insoles with only ATR-IR? ???Is this technique suitable for routine forensic analysis of copolymer samples? Justify your answer.

Description Volkswagen emissions scandal: Write one page term paper maximum about this topic.