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Given a sample of h o ice being fed with a constant flux of heat sketch a plot of the temperature

 
 

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1.​What is true about sample preparation for NMR? a. Samples for 13C NMR should be concentrated, and for 1H NMR should ...

d for 1H NMR should be dilute. b. Samples for 13C NMR should be dilute, and for 1H NMR should be concentrated. c. Samples for 13C NMR and 1H NMR should both be concentrated. d. Samples for 13C NMR and 1H NMR should both be dilute. 3. What is the proper way to dispose of an NMR sample that had deuterated chloroform (CDCl3) as the solvent? a. Placement down the drain. b. Placement in the non-halogenated organic waste container. c. Placement in the halogenated organic waste container. d. Placement in the oven for evaporation. 4. Which feature of a 1H NMR spectrum can provide information about the number of inequivalent kinds of hydrogen in the structure? a. chemical shift b. coupling c. integration d. None of the above. 5. Which feature of a 1H NMR spectrum can provide information about the number of neighboring hydrogens that a given hydrogen in the structure has? a. chemical shift b. coupling c. integration d. None of the above. 6. Which feature of a 1H NMR spectrum can provide information about the number of hydrogens responsible for each signal? a. chemical shift b. coupling c. integration d. None of the above 7. An unknown has a specific rotation (i.e., a rotation unequal to 0°) as measured with a polarimeter. What is true about the unknown? a. The structure contains at least one chirality center. b. The structure contains no chirality centers. c. The structure has a plane of symmetry. d. None of the above. 8. True or False: Conjugation increases the wavenumber of absorption in the IR spectrum. True False 9. What group classification does a solid unknown most likely belong to if its melting point is greater than 250 °C? a. carboxylic acid b. amino acid c. amine d. acid derivative 10. True or False: If a liquid unknown freezes when placed in an ice-water bath for 10 minutes, the melting point of the unknown is between 0 °C and 25 °C. True False
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2.QUESTION THREE Considering the information given in Question One the owner of the small chain is interested in whether or not ...

interested in whether or not there is a benefit trying to locate their restaurants in shopping centre food courts. Food Court Not in Food Court Average Revenue 1609.69 1710.0 Standard deviation 190.85 150.83 Sample size 12 38 a. Conduct a test at the 5% level of significance to determine if there is a difference in average revenue between restaurants located in food courts to those that aren’t. Make whatever assumptions and carry out any checks that are necessary to conduct this test. (5)
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3.AP Chem AB FRQ Question 1 A sample consisting of 50. mL of 0.400 M solution of the acid, HClO4, is titrated ...

titrated with a 0.200 M solution of the base, LiOH. Write the balanced chemical reaction for neutralization reaction: HClO4 (aq) + LiOH (aq) → LiClO4 (aq) + H2O (l) Write the NET ionic equation for the neutralization reaction. OH⁻ (aq) + H⁺ (aq) → H2O (l) Compute the pH of the titration solution. Show your work i) before any of the base is added ii) after 25. mL of base is added iii) after 50. mL of base is added A student performs the titration with the same chemicals but with smaller volumes of each chemical . Which of the following titration curves could represent the titration. Explain A because this entails a strong acid and a strong base. Question 2 A student performs a titration of an unknown acid with a strong base and gets the following titration curve: a) The student consults the list of pKa of acids shown below. If the acid is listed in the table below, which is the most likely identity of the unknown acid? Explain. Acid Ka HF 7.2 x 10-4 CH3COOH 1.8 x 10-5 H2CO3 4.3 x 10-7 HBrO 2.0 x 10-9 The unknown acid is HBrO because the calculated Ka is in between 50^-4 and 50^-6 and 2.0 x 10^-9 lies in between them. b) What is the initial molarity of the acid? 10^-3 = 0.001M Question 3 a) Describe the components and the composition of an effective buffer solution. Explain how the components of the buffer allow the buffer to maintain its pH. An effective buffer solution has a weak acid and its conjugate base or a weak base and its conjugate acid. A buffer solution is most effective when the ratio of its component concentrations is close to 1, also when the pH is equal to the pka of the acid.; The components of the buffer allow the buffer to maintain its pH because buffers can absorb excess H+ions or OH– ions. An employer is interviewing four applicants for a job as a laboratory technician and asks each how to prepare a buffer solution with a pH of 5.0. The following constants may be helpful: hydrazoic acid, pKa = 4.74 Boric acid, pKa = 9.23 Archita A. says she would mix equal molar solutions of hydrazoic (HN3) and sodium azide (NaN3) solutions. Bradley B. says she would mix equimolar Boric acid (H3BO3) and HCl solutions. Carlos C. says he would mix equimolar Boric Acid (H3BO3) and sodium dihydrogen borate (NaH2BO3) solutions. Delia D. says he would mix equimolar hydrazoic Acid (HN3) and NaOH solutions. b) Which of these applicants has given an appropriate procedure? Explain your answer Delia because she is using Sodium hydroxide which results in a pH of 5. NaOH is a strong base and in order to have an effective buffer a weak acid must be incorporated which is the HN3. c) Explain what is wrong with the erroneous procedures. The rest all incorporate a strong acid and a strong base or a weak acid and a weak base which don’ result in an effective buffer. d) The applicants have access to the 1 Liter volumes of each of the solutions listed above. They have access to graduated cylinders. In order to make 1.0 Liter of the correct 5.0 buffer solution, what volumes of the two chemicals must be mixed?
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4.Exercise 4) A fair coin is tossed. If it lands heads, a fair four-sided die is thrown (with values 2,3,4,7). If ...

2,3,4,7). If it lands tails, a fair six-sided die is thrown (with values 3,4,5,6,7,9). Regardless of which die is used, Alice eats n grains of rice, where n is the largest prime factor of the die result (for example, the largest prime factor of 9 is 3). (a) What is the conditional probability that the coin lands heads, given that Alice eats three grains of rice? (b) Suppose that the entire experiment is conducted twice on the following day (starting with a new coin toss on the second run-through). What is the conditional probability that the coin lands heads on both run-throughs, given that Alice eats a total of five grains of rice during the two run-throughs? (Do not count the two grains from part (a) in part (b); we assume two brand new experiments, each with a new coin toss. Start your solution by defining a suitable partition of the sample space. Please use an appropriate notation and/or justification in words, for each value that you give as part of your solution.) Exercise 5) Alice and Bob throw an unfair coin repeatedly, with probability 2/5 of landing heads. Alice starts with £2 and Bob starts with £3 . Each time the unfair coin lands heads, Alice gives Bob £1 . Each time the unfair coin lands tails, Bob gives Alice £1 . The game ends when one player has £5 . (a) Draw a labelled Markov chain describing the problem, and write down a transition matrix P. Write down the communication classes, and classify them as either recurrent or transient. (b) Using the transition matrix, calculate the probability that Alice loses all of her money in exactly four tosses of the unfair coin. (c) Calculate the (total) probability that Alice loses all of her money (before Bob loses all of his). (d) Calculate the expected (mean) number of tosses of the unfair coin, for the game to end.
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5.dehydrated cobalt (ii) chloride Be sure to include subheadings (see bold text below) formulas, and units. Chemical Equation: Write a generic ...

units. Chemical Equation: Write a generic chemical equation for the dehydration of cobalt (II) chloride ∙ x hydrate (include the state symbols of the reactant and two products). [T2] Mass of Reactants and Products: a) Calculate the initial mass of the hydrated cobalt (II) chloride. [T1] b) Calculate the final mass of the anhydrous cobalt (II) chloride remaining in the cruiio8icible. [T1] c) Calculate the mass of water given off by the sample of hydrated cobalt (II) chloride. [T1] Moles of Products: a) Calculate the moles of anhydrous cobalt (II) chloride remaining in the crucible. [T1] b) Calculate the moles of water released from the hydrate. {T1] 4. Mole Ratio a) Create an experimental mole ratio between the b) and a). [T1] 5. Formula of Hydrate: State the chemical formula you have determined for this hydrate. Round the formula to the closest whole number value for x. [T1] Discussion/Conclusion Questions: [T6] Based on the chemical formula of the hydrate, calculate the percentage composition (percent by mass) of the hydrated cobalt (II) chloride. Remember to determine the percentage of each element (Co, Cl, H, and O). [T2] A possible source of systematic error in this experiment is insufficient heating. Suppose that the hydrate was not completely converted to the anhydrous form. Describe how this would affect: the calculated percent by mass of water and the experimental molecular formula (i.e. would x be higher, lower or the same). Suppose a student spilled some of the hydrated cobalt (II) chloride. Describe how this would affect the calculated percent by mass of water (would it be higher, lower or the same) and the experimental chemical formula of the hydrate. [T2]
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6.A food company wishes to determine whether a newly designed potato chip bag increases the length of time a bag ...

time a bag of chips remains fresh on the grocery shelf. A random sample of potato chips with the old design of the bag was compared to a random sample of potato chips with the new bag. Summary statistics pertaining to the number of days the chips remained fresh are given below. At a 95% level of confidence (α = .05), the company wishes to investigate if the new bag has an increased freshness time over the old bag. Summary Statistics New Bag Old Bag (Sample #1) (Sample #2) Sample Mean 21.2 days 20.8 days Sample Standard Deviation 2.5 days 2.8 days Sample Size 45 50 What is the correct Null and Alternate Hypothesis? Select one: a. H_0: \mu_d>0\;\; H_1: \mu_d < 0 b. H_0: \mu_1>\mu_2 \;\;H_1:\mu_1 \leq \mu_2 c. H_0: \mu_d =0\;\; H_1: \mu_d < 0 d. H_0: \mu_1\leq\mu_2 \;\;H_1:\mu_1 > \mu_2
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7.Weight loss: In a study to determine whether counseling could help people lose weight, a sample of people experienced a ...

eople experienced a group-based behavioral intervention, which involved weekly meetings with a trained interventionist for a period of six months. The following data are the numbers of pounds lost for 14 people, based on means and standard deviations given in the article. Assume the population is approximately normal. Perform a hypothesis test to determine whether the mean weight loss is greater than 20 pounds. Use the =α0.10 level of significance and the critical value method. 22.5 28.5 7.6 24.1 21.5 12.9 17.3 21.2 37.6 33.8 12.1 36.3 24.1 19.4
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8.2. PODStat5 4.E.031. The standard deviation alone does not measure relative variation. For example, a standard deviation of $1 would be considered ...

, a standard deviation of $1 would be considered large if it is describing the variability from store to store in the price of an ice cube tray. On the other hand, a standard deviation of $1 would be considered small if it is describing store-to-store variability in the price of a particular brand of freezer. A quantity designed to give a relative measure of variability is the coefficient of variation. Denoted by CV, the coefficient of variation expresses the standard deviation as a percentage of the mean. It is defined by the formula CV = 100(s/ x ). Consider two samples. Sample 1 gives the actual weight (in ounces) of the contents of cans of pet food labeled as having a net weight of 8 oz. Sample 2 gives the actual weight (in pounds) of the contents of bags of dry pet food labeled as having a net weight of 50 lb. There are weights for the two samples. Sample 1 7.7 6.8 6.5 7.2 6.5 7.7 7.3 6.6 6.6 6.1 Sample 2 50.7 50.9 50.5 50.3 51.5 47 50.4 50.3 48.7 48.2 (a) For each of the given samples, calculate the mean and the standard deviation. (Round all intermediate calculations and answers to five decimal places.) For sample 1 Mean Standard deviation For sample 2 Mean Standard deviation (b) Compute the coefficient of variation for each sample. (Round all answers to two decimal places.) CV1 CV2
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1.AU MAT 120 Systems of Linear Equations and Inequalities Discussion

mathematicsalgebra Physics