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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.a) Carbon tetrachloride is an organic compound with the chemical formula CCl4. It is a colorless liquid with a “sweet” smell. i. ...

quid with a “sweet” smell. i. Using the ground state electron configuration and excited state electron configuration explain the hybridization of the central Carbon (C) atom. (7 Marks) ii. Identify the orbitals that overlap to form the C-Cl bond. Draw a diagram to show the orbital overlap. (3 Marks) iii. What is the bond angle of CCl4? (1 Mark) b) Consider a Fluorine atom (F) and a Fluorine anion (F-). Which of these two species would you expect to have a larger radius? Explain your answer. (5 Marks) c) Explain why the first ionization energy of Aluminum (Al) is less than that of Magnesium (Mg). (4 Marks) d) Assume the atom Oxygen(O) can form both cationic(O+) and anionic(O-) species. Place the following species in order of increasing first ionization energy, starting with the lowest. O+, O, O- (5 Marks) 4. a) Sea water contains roughly 28.0 g of NaCl per liter. (NaCl molar mass = 58.44 gmol-1). i. Calculate the number of moles of NaCl in a liter of sea water. (2 Marks) ii. Calculate the molarity of NaCl in sea water. (4 Marks) iii. Calculate the mass by volume percent (W/V) of NaCl in sea water. (4 Marks) Lowest first ionization energy ………………… ….. Intermediate ionization energy ………………… ….. Highest first ionization energy …………………
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3.Consider the following unbalanced chemical equation: Fe3O4 (aq) + CO (g) → CO2 (g) + Fe (s) What will be the coefficient ...

What will be the coefficient in front of CO in the balanced chemical equation? If there is no coefficient in front of CO in the balanced equation, enter 1 as the answer.
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4.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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5.(a) A 20.0 L container at 303 K holds a mixture of two gases with a total pressure of 5.00 ...

here are 2.00 mol of Gas A in the mixture, how many moles of Gas B are present? (R = 0.0821 L • atm/(K • mol)) (b) The gas in a 250. mL piston experiences a change in pressure from 1.00 atm to 2.80 atm. What is the new volume (in mL) assuming the moles of gas and temperature are held constant? (c) Small quantities of Oxygen can be produced by the decomposition of mercury(II) oxide as shown below. Typically, the oxygen gas is bubbled through water for collection and becomes saturated with water vapor. Atomic weight of HgO = 216.6 amu, Atomic weight of Oxygen = 32.00 amu) 2 HgO(s) → 2 Hg(ℓ) + O₂(g) (i) Assuming that 3.05 grams of HgO was used in this reaction, determine the number of moles of oxygen gas formed.(According to the above chemical equation) (ii) Assuming 310. 0 mL of Oxygen gas was collected at at 29°C, calculate the pressure of the Oxygen gas that was collected. (R = 0.0821 L • atm/(K • mol) (iii) If the vapor pressure of water at this temperature equals to 0.042 atm, calculate the pressure reading of this experiment.
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7.. When 4.00-L of 0.0290 M aluminum sulfate and 3.25-L of 0.0700 M Pb(NO3)2 solutions are mixed, solid lead (II) ...

d lead (II) sulfate precipitates (a) Write a balanced chemical equation for the reaction (b) Write the net ionic equation for the reaction (c) What type of reaction is occurring? (d) What is the limiting reagent? The excess reagent? (e) How many grams of lead (II) sulfate are formed? (f) In the lab, a chemistry student mixed the two solutions together and formed 9.40 g of lead (II) sulfate. What percent yield did the student obtain?
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8.So in drug discovery, I know it basically comes down to finding a chemical which binds with the target ligand. ...

et ligand. But, I do not get the big picture, I'm assuming the drug always changes metabolism, what what happens on the organelle-,cell-,organ-,organ system-, and organism-scales? I'm sure all of this needs to be checked so companies are making sure the drug is not toxic. Thanks.
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1.AU MAT 120 Systems of Linear Equations and Inequalities Discussion

mathematicsalgebra Physics