Explain why grain boundaries move towards their centre of curvature during grain growth but away from their centre of curvature during recrystallization.

We have a closed system. Answer the following questions. It it is correct, explain why using concepts and few examples. If it wrong, justify with an example and explain the conceptual reason it is wrong 1- Which is greater in a bond breaking reaction, ∆H or ∆U? 2- Which is greater in a bond forming reaction, ∆H or ∆U? 3- Which is greater in constant pressure process where the volume decrease, ∆H or ∆U? Assume there is piston that move in this case. System can exchange heat and work

A 10.0-mL solution of 0.300 M NH3 is titrated with a 0.100 M HCl solution. Calculate the pH after the following additions of the HCl solution: a) 0.0 mL b) 10.0 mL c) 20.0 mL d) 30.0 mL e) 40.0 mL (Please explain all steps and write clearly)

Calculate the pH change that results when 12 mL of 5.2 M NaOH is added to 789 mL of each the following solutions. (See the Acid-Base Table.) (a) pure water 5.85 Correct: Your answer is correct. (b) 0.10 M NH4Cl 4.53 Incorrect: Your answer is incorrect. (c) 0.10 M NH3 1.72 Incorrect: Your answer is incorrect  (d) a solution that is 0.10 M in each NH4+ and NH3

I would be grateful for some help or solution regarding these Quantum Chemistry questions. a) Why can the electronic wave function not be constructed as the simple product of one electron wave function, but needs to be constructed as a so-called Slater determinant? b) What is the consequence of using the Slater determinant instead of the simple product in terms of electron-electron interactions?

Part 4 of 4 - Question 4 of 4 0.5 Points The literature melting point for bupropion hydrochloride is 233-234 "C. You finished your synthesis of bupropion hydrochloride and observe a melting point range of $213-215^{\circ} \mathrm{C}$. Is your product pure? Select the statement that applies. A. Yes. The melting point range is narrow. B. No. The melting point range is broad. C. No. The melting point is not close to literature. D. Yes. The melting point is close to literature. Reset Selection

Give 5 Matching Type Laboratory Apparatus Give 5 Vessel Type Laboratory Apparatus

The Ka for HF is 7.2 x 10-4 . What is ΔG at 25oC for a reaction mixture that is 1.5 x 10-3 M in F– , 4.5 x 10-2 M in HF with a pH of 2.75? The answer should be in kJ.

Consider the titration of a $25.0-\mathrm{mL}$ sample of $0.175 \mathrm{M} \mathrm{CH}_{3} \mathrm{NH}_{2}$ with $0.150 \mathrm{M} \mathrm{HBr}$. Determine each quantity. a. the initial $\mathrm{pH}$ b. the volume of added acid required to reach the equivalence point c. the $\mathrm{pH}$ at $5.0 \mathrm{~mL}$ of added acid d. the $\mathrm{pH}$ at one-half of the equivalence point e. the $\mathrm{pH}$ at the equivalence point f. the $\mathrm{pH}$ after adding $5.0 \mathrm{~mL}$ of acid beyond the equivalence point

Question 4 of 11 Submit Which of the following $1.0 \mathrm{M}$ solutions would have the highest pH? \begin{tabular}{|c|c|c|c|} \hline $\begin{array}{c}\text { Weak } \\ \text { Acid }\end{array}$ & $\mathbf{K}_{\mathbf{a}}$ & $\begin{array}{c}\text { Weak } \\ \text { Base }\end{array}$ & $\mathbf{K}_{\mathbf{b}}$ \\ \hline $\mathrm{HCN}$ & $4.9 \times 10^{-10}$ & $\mathrm{HONH}_{2}$ & $1.1 \times 10^{-8}$ \\ \hline $\mathrm{HNO}_{2}$ & $4.5 \times 10^{-4}$ & $\mathrm{NH}_{3}$ & $1.8 \times 10^{-5}$ \\ \hline $\mathrm{HIO}$ & $2.3 \times 10^{-11}$ & $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}$ & $4.3 \times 10^{-10}$ \\ \hline $\mathrm{HBrO}$ & $2.5 \times 10^{-9}$ & $\mathrm{H}_{2} \mathrm{NNH}_{2}$ & $1.3 \times 10^{-6}$ \\ \hline $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COOH} 6.3 \times 10^{-5}$ & $\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{~N}$ & $1.7 \times 10^{-9}$ \\ \hline \end{tabular} A) $\mathrm{KCN}$ B) $\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{NHCl}$ C) $\mathrm{NalO}$ D) $\mathrm{NH}_{4} \mathrm{Br}$

IV) Synthesis - Propose syntheses for the molecules shown below. Please be sure to include key reagents in your solutions. It is not necessary to show mechanisms or retrosynthetic analyses in your solutions. Messiness may result in lost points. Note: There is often more than one correct answer! A) All carbons in the molecule must come from benzene or acetic acid. B) Design your own synthesis problem! Using any of the reactions we have talked about in this class, try to create a synthesis problem (like the one above). Include a plausible synthetic route as an answer. Who knows, maybe your question will be featured on the Final...

Given the following information, calculate the heat of solution for the salt in the unit of $\mathrm{kJ}$. A calorimeter contains $44.96 \mathrm{~g}$ of water. The temperatures of the calorimeter and water are both 22.6 degrees Celsius. $2.42 \mathrm{~g}$ of salt is dissolved in the water. Then, the temperature falls to $\left(2.0 \times 10^{\wedge} 1\right)$ degrees Celsius. (Note: the heat capacity of this calorimeter is $30.1 \mathrm{~J} /$ degree Celsius. Pay attention to the sig. figs. in your calculation.)

Question 11 of 17 A neutral solution of water at a particular temperature has a concentration of $\mathrm{OH}^{-}$of $8.3 \times 10^{-7} \mathrm{M}$. What is $\mathrm{Kw}$ at this temperature?

1) 1A) "A compound can oil out if the boiling point of the recrystallization solvent is higher than the melting point of the compound". Is this statement true or false?   1B) Choose the best explanation for your selection above. 1-Organic compounds will be solids at all temperatures. 2-Every recrystallization involves a step when the compound is an oil. 3-The compound may melt rather than dissolve if the solvent temperature is too high.   2) The solubility of a compound is 35.6 g/100 mL at 25°C; and 39.1 g/100 mL at 108°C. If a saturated solution of the compound at 108°C is allowed to slowly cool to 25°C, what is the maximum yield (in %) of solid crystals that can be obtained?   3) A student dissolves 80 mg of a crude product in 4.5 mL (the minimum required) of methanol at 25 °C. She cools the solution in an ice bath and obtains crystals. The crystals are recovered by filtration and rinsed with 0.5 mL of ice-cold methanol. After drying, the weight of the crystals is 5 mg. How should the student improve the yield? a) The student should use more cold solvent to increase crystal formation. b) The student should increase the temperature of the solvent when dissolving to increase differential solubility. c) The student should add more of the crude product to decrease its solubility in the solvent.    4) When butanoic acid reacts with sodium borohydride, 1-butanol is not obtained. However, bubbling is still observed, and heat is produced. 4A) Why is 1-butanol not obtained? a) Sodium borohydride is not reactive enough to reduce a carboxylic acid to an alcohol. b) 1-butanol is an oxidation product of the carboxylic acid, not a reduction. c) The butanoic acid bubbles away before it can react with the sodium borohydride.   4B) What are the products of this reaction? Carbon dioxide gas Sodium butanoate Hydrogen gas 1-butanone Oxygen gas Butane    5) The reagent below is diisobutylaluminum hydride, or DIBAL. Like sodium borohydride, it is a source of nucleophilic hydride. Predict the configurations of each stereocentre in the product of the following reaction (with appropriate work-up) and provide a justification for your choice. Unlike NaBH4, reductions performed with DIBAL require equimolar amounts of DIBAL and substrate. Can you explain this difference?

Consider the reaction data. A⟶products ? (?) ? (?−1) 325 0.394 725 0.678 What two points should be plotted to graphically determine the activation energy of this reaction? To avoid rounding errors, use at least three significant figures in all values. ?1= ?1= ?2= ?2= Determine the rise, run, and slope of the line formed by these points. rise: run: slope: What is the activation energy of this reaction? ?a=-------J/mol

If you were provided with a mixture containing 2-propanol and 2-methylfuran, which distillation technique should be used to separate the components? Refer to the experiment information in the lab manual to answer this question. distillation technique: fractional Which of the following statements are correct regarding separating a mixture containing ethanol and 2-methyfuran? Refer to the experiment information in the lab manual to answer this question. Fractional distillation should be used to separate these compounds If pure, one of the compounds will result in an IR spectrum showing significant signals at 3105, 2942, 1619, $1198 \mathrm{~cm}^{-1}$ These compounds are easily distinguishable by IR spectroscopy It is difficult to distinguish these compounds by IR spectroscopy If pure, one of the compounds will result in an IR spectrum showing significant signals at 3397, 2931, 2254, $1738 \mathrm{~cm}^{-1}$ Simple distillation should be used to separate these compounds based on \begin{tabular}{|c|c|c|c|} \hline Compound & Structure & Aroma & b.p. $\left({ }^{e} \mathrm{C}\right)$ \\ \hline Acetone & & Apple & $56-57$ \\ \hline 2-Methylfuran & & Ethereal & $63-66$ \\ \hline Ethyl Acetate & & Fruit, Brandy & $75-77$ \\ \hline Ethanol & & Alcohol & $77-79$ \\ \hline 2-Butanone & & Ethereal & 79.81 \\ \hline $\begin{array}{c}\text { 2-Propanol } \\ \text { (Isopropyl alcohol) }\end{array}$ & & Butter & $81 \cdot 83$ \\ \hline Pentanal & & Berry & $98-99$ \\ \hline 2-Pentanone & & Banana & $103-105$ \\ \hline Ethyl Isobutyrate & & Citrus & $112-113$ \\ \hline 2-Pentanol & & Oily & $118-120$ \\ \hline \end{tabular}

The value of $\mathrm{K}_{c}$ for the reaction between water vapor and dichlorine monoxide is 0.0900 at $25^{\circ} \mathrm{C}$. \[ \mathrm{H}_{2} \mathrm{O}(\mathrm{g})+\mathrm{Cl}_{2} \mathrm{O}(\mathrm{g}) \rightleftharpoons 2 \mathrm{HOCl}(\mathrm{g}) \] 2nd attempt Part 1 ( 0.3 point) Determine the equilibrium concentration of $\mathrm{H}_{2} \mathrm{O}$ if the starting concentrations of both reactants are $0.003521 \mathrm{M}$, with $[\mathrm{HOCl}]_{0}=$ $0.000 \mathrm{M}$ M Part 2 ( 0.3 point) Determine the equilibrium concentration of $\mathrm{Cl}_{2} \mathrm{O}$. M M Part 2 ( 0.3 point) Determine the equilibrium concentration of $\mathrm{Cl}_{2} \mathrm{O}$. M Part 3 ( 0.3 point) Determine the equilibrium concentration of $\mathrm{HOCl}$. M 1st attempt

Radio astronomers use radio frequency waves to identify the elements in distant stars. One of the lines that is studied is designated the 272α line. This spectral line refers to the transition in hydrogen from ?i=273 to ?f=272. Calculate the wavelength ? and frequency ? of the electromagnetic radiation that is emitted for the 272α transition. ?= F=

Consider the following reaction in the forward direction. Identify the conjugate acid: CH₃O⁻ + H₂O ⇌ CH₃OH + OH⁻ A) CH₃O⁻ B) H₂O C) CH₃OH D) OH⁻

6. The structures of naturally occurring geosmin (responsible for the aroma of fresh beetroot) and tartaric acid (found in grapes) are shown below. geosmin b.p. $270^{\circ} \mathrm{C}$ $[\alpha]_{D}=-16.5$ a) Draw structures clearly depicting stereochemistry for: i) A stereoisomer of geosmin which has a specific rotation of +16.5 . ii) A stereoisomer of geosmin which does not have a boiling point of $270^{\circ} \mathrm{C}$. iii) A constitutional isomer of tartaric acid which has a specific rotation of $0^{\circ}$. iv) A stereoisomer of tartaric acid which has a specific rotation of $0^{\circ}$. v) Explain briefly why tartaric acid would be far more soluble in water than geosmin.

1. The accepted densities are shown in the table below. If the calculated values by you are 2.9 g/cm3 for Aluminum, 1.0 g/cm3 for Acrylic, and 1.1 g/cm3 for Polyethylene, respectively, how do these numbers compare to the calculated values? What sources of error could cause the differences? Substance Density (g/cm3) Aluminum 2.7 Acrylic 1.2 Polyethylene 0.9 2. People float in saltwater more easily than they do in freshwater. Likewise, some objects that sink in freshwater will float in saltwater. Based on these facts, what can be inferred about the density of saltwater and the density of freshwater? Explain the conclusion. 3. When ice melts in a glass of regular soda without being disturbed, the following observations can be made: (1) the ice floats in the soda, (2) water from melted ice remains above the soda, and (3) the ice floats in the water. What can be inferred about the relative densities of ice, water, and regular soda? 4. A crude oil spill from a deep-water drilling platform is always possible. The density of crude oil ranges from 0.8 g/cm3 to 0.9 g/cm3. How might the density of crude oil affect its impact on wildlife, both aquatic and terrestrial? How might its density affect clean-up operations? How might the density of crude oil affect potential fires?

1. What does IR spectroscopy measure in a molecule? What are the units? Define each of the abbreviations used to describe absorbance peaks (m, w, s, b, n, sh).   2. How can you tell the difference between an alcohol, a primary amine, and a secondary amine in the N-H or O-H peak? Show examples. 

4. A $110.0-\mathrm{g}$ sample of metal at $82.00^{\circ} \mathrm{C}$ is added to $110.0 \mathrm{~g}$ of $\mathrm{H}_{2} \mathrm{O}(l)$ at $27.00^{\circ} \mathrm{C}$ in an insulated container. The temperature rises to $30.56^{\circ} \mathrm{C}$. Neglecting the heat capacity of the container, what is the specific heat of the metal? The specific heat of $\mathrm{H}_{2} \mathrm{O}(l)$ is $4.18 \mathrm{~J} /$ $\left(\mathrm{g} \cdot{ }^{\circ} \mathrm{C}\right)$.

-5.95g of cobalt(II) carbonate were added to 40cm3 of hydrochloric acid, concentration 2.0mol/dm3 . I] Calculate the maximum yield of cobalt(II) chloride-6-water and show that the cobalt(II) carbonate was in excess. CoCO3 + 2HCl → CoCl2 + CO2 + H2O CoCl2 + 6H2O → CoCl2.6H2O } maximum yield: } number of moles of HCl used = } number of moles of CoCl2 formed = } number of moles of CoCl2.6H2O formed = } mass of one mole of CoCl2.6H2O = 238g }maximum yield of CoCl2.6H2O = …………………………………………………..…..…g to show that cobalt(II) carbonate is in excess: number of moles of HCl used = ……………………….……… (use your value from above) mass of one mole of CoCO3 = 119g number of moles of CoCO3 in 5.95g of cobalt(II) carbonate = ………………………… (ii) Explain how these calculations show that cobalt(II) carbonate is in excess.

For the equilibrium 2IBr(g) ⇌ I₂(g) + Br₂(g) Kc = 8.50 × 10⁻³ at 150°C. If 0.0410 mol of IBr is placed in a 1.0-L container, what is the partial pressure of I₂(g) in atm after equilibrium is reached?

The fundamental difference between gravimetric and volumetric analysis: a gravimetric analysis involves a mass measurement as the determining measurement, while a volumetnc analysis involves a volume measurement as the determining measurement, true or false? Select one: True False

What is the rate for the second order reaction A → Products when [A] = 0.201 M? (k = 0.761 M⁻¹s⁻¹)

7) A Mohr titration is a precipitation titration used to analyze the amount of $\mathrm{Cl}^{-}$or $\mathrm{Br}^{-}$ions in a sample. The titrant is silver nitrate $\left(\mathrm{AgNO}_{3}\right)$ and reacts with the chloride ions to form a white silver chloride $(\mathrm{AgCl})$ precipitate according to the following reaction: \[ \mathrm{Ag}_{(\mathrm{aq})}+\mathrm{Cl}_{(\mathrm{aq})} \rightarrow \mathrm{AgCl}_{(\mathrm{s})} \] If potassium chromate $\left(\mathrm{K}_{2} \mathrm{CrO}_{4}(\mathrm{aq})\right)$ is added as an indicator, after all of the $\mathrm{AgCl}$ has formed, an orange/red precipitate (silver chromate, $\mathrm{Ag}_{2} \mathrm{CrO}_{4}$ ) will appear at the end point according to this reaction: \[ 2 \mathrm{Ag}_{(\mathrm{aq})}+\mathrm{CrO}_{4(\mathrm{aq})} \rightarrow \mathrm{Ag}_{2} \mathrm{CrO}_{4(\mathrm{~s})} \] A student placed $50.00 \mathrm{~mL}$ of a water sample into an Erlenmeyer flask. Three drops of $\mathrm{K}_{2} \mathrm{CrO}_{4}$ (aq) were then added to the flask. The buret contained $0.080 \mathrm{M}$ $\mathrm{AgNO}_{3}(\mathrm{aq})$ as the titrant. If $15.70 \mathrm{~mL}$ of titrant was used to reach the end point, calculate the amount of chloride ions in Analyte containing $\mathrm{K}_{2} \mathrm{CrO}_{4}$ indicator White $\mathrm{AgCl}$ precipitate Orange/red $\mathrm{Ag}_{2} \mathrm{CrO}_{4}$ precipitate $\mathrm{mg} / \mathrm{L}$ found in the sample.

Name Lab Partner PRELABORATORY EXERCISE Lab Section Date 1 Name three physiological properties of aspirin. 1 2 3 2 Naproxen is a potent painkiller found in the drug Aleve*. Based on the structure of naproxen, would you expect its analgesic properties to result from the same chemical reaction with the human body that makes aspirin a good pain rellever? Explain your answer. naproxen 3 A student trying to prepare aspirin begins with $3.25 \mathrm{~g}$ of salicylic acid and excess acetic anhydride. a What is the student's theoretical yleld of aspirin? Show your work. b If the student obtains $2.86 \mathrm{~g}$ of aspirin, what is her percent yleld? Show your work.

2-40. Exactly $750.0 \mathrm{~mL}$ of a solution that contains $500.0 \mathrm{ppm}$ of $\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}$ is mixed with $200.0 \mathrm{~mL}$ of a solution that was $0.04100 \mathrm{M}$ in $\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}$. (a) What mass of solid $\mathrm{BaSO}_{4}$ is formed? (b) What is the molar concentration of the unreacted reagent $\left[\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}\right.$ or $\left.\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}\right]$ ? 2-18. Calculate the molar $\mathrm{H}_{3} \mathrm{O}^{+}$ion concentration of a solution that has a $\mathrm{pH}$ of (a) 3.73 . (b) 3.28 . (c) 0.59 . (d) 11.29 . (e) 7.62 . (f) 5.19 . (g) -0.76 . (h) -0.42 .