Chemistry question and answers for July 05, 2023
- Q At 650 K, the reaction MgCO3(s)⇌MgO(s)+CO2(g) has Kp=0.026. A10.0-L container at 650 K has 1.0 g of MgO(s) and CO2 at P=0.260atm. The container is then compressed to a volume...
- Q When is it a good idea to use flash chromatography?
- Q Only one (cis) isomer of product is formed in the Diels-Aldercycloaddition. Explain why one product is formed, and why is hasthat particular stereochemistry ( the Diels-Alder cycloaddition inthis case is...
- Q 50.0 mL of 2.00 mol/L HNO3 solution and 50.0 mL of 1.00 mol/LNaOH solution, both at 20.0 degree Celsius, were mixed in acalorimeter. Calculate the molar heat of neutralization of...
- Q 6. I suggest using Excel to answer this question. Consider thefollowing distribution of polymer chains:5 chains of degree of polymerization 1025 chains of degree of polymerization 10050 chains of degree...
- Q A concentrated solution of sucrose, C12H22O11, contains 233.2 gdissolved in 397.07 g water. The density of the solution is 1.1507g mL-1 Calculate; weight percent, mol fraction, molality, andmolarity of C12H22O11...
- Q Determine the concentrations of Na2CO3, Na , and CO32– in asolution prepared by dissolving 2.61 × 10–4 g Na2CO3 in 2.25 L ofwater. Express all three concentrations in molarity. Additionally,express...
- Q You are given a sample that has1.3 mg/ml of purified protein. The molecular weight is 37,000Daltons.a) the absorbance in a 1cm cuvette is 0.93. calculate the molarextinction coefficient. Be sure...
- Q Professor Van Eggmon thinks that dissolving eggshells at 74.1o Fis easier than cracking eggs. The shells are made of calciumcarbonate (CaCO3), which reacts with acetic acid (CH3COOH) to formcarbon dioxide...
- Q Erioglucine is a blueÂcolored dye that absorbs its complementarycolor, red, in aqueous solution around 645 nm. Unfortunately, thelocal distilled water supply is consistently contaminated with atrace amount of a metal...
- Q The mean free path of neon is 6.4 x 10^-2 m at a pressure of1.00 x 10^-4 atm and 298 K. A neon atom has a mass of 3.351 x10^-26...
- Q Areaction has a rate constant of 1.23 x 10 ^-2 /s at 400 K and.688/s at 450K.What is the activation barrier for the reaction and what isthe value of the...
- Q Decide if the compound/ion listed can satisfy the octet rule(duet rule for H), if so choose Satisfies Octet Rule from the dropdown menu. If the compound/ion cannot satisfy the octet...
- Q 1) What is/are the spectator ion(s) for the following chemicalreaction? Check all that apply.Pb(NO3)2(aq) + Na2S(aq) --> PbS(s) + 2 NaNO3(aq)a)Pb2+ ionb) Na+ ionC) S2- ionD)NO3- ion----------------------------------------------------------------Question 2What is the...
- Q You wish to dissolve benzaldehyde, a liquid at 25 degreescelsius, in an appropriate liquid solvent. Which of the followingsubstances would probably be the best choice for a solvent at thattemperature?...
- Q Dolomite, [CaMg(CO3)2] is found in a soil sample. A geochemisttitrates 24.65 g of soil with 57.85 mL of 0.3315M HCl. What is themass % of dolomite in the soil? (...
- Q Record your values for ΔHA and ΔHB below: Mg (s) + 2 HCl (aq) →MgCl2 (aq) + H2 (g) ∆HA = __-4.70 x 105 kJ/mol Mg_ MgO (s) + 2...
- Q The Ka of a monoprotic weak acid is 5.13 × 10-3. What is thepercent ionization of a 0.179 M solution of this acid?
- Q mass of empty beaker-----------132.862 gmass of beaker with unknown sample--------133.343gass of crucible------------41.962gmass of crucible with BaSO4---------------42.631gA) calculate the number of moles of BaSO4 that werecollectedB) calulate the number of moles...
- Q A buffer with a pH of 4.06 contains 0.13 M of sodium benzoateand 0.18 M of benzoic acid. What is the concentration of [H ] inthe solution after the addition...
- Q In the laboratory, a general chemistry student measured the pHof a 0.550 M aqueous solution of formicacid, HCOOH to be1.987.Use the information she obtained to determine the Ka forthis acid.Ka(experiment)...
- Q 4. An ideal gas in a moveable piston is allowed to reversiblyexpand by slowly heating at constant pressure.a. (10 pts) Derive the equation for the work done (w reversible)as a...
- Q Sketch a graph for a titration of a weak acid (burette) against25cm^3 of a strong base (conical flask). Assume that both haveconcentrations of 0.5M. Label Axes.
- Q 2. A 1.00L piston with 1.00mole of an ideal gas at 298.0K and1.00bar is isothermally and reversibly compressed to a final volumeof 0.100L, then irreversibly expanded in 1 step to...
- Q What is the concentration of ammonia in a solution if 20.90ml ofa 0.1110 M solution of HCl are needed to titrate a 100.0ml sampleof a solution?
- Q What is the percent dissociation of a 0.0217 M solution ofchloroacetic acid, (HC2H2ClO2 )? (Ka = 1.35 × 10−3 )
- Q What is the pH of a 2:1 mixture of H2PO4– to HPO42– at 0.050 Mionic strength? (See the table for the activity coefficients.)
- Q At 473 K, for the elementary reaction2NOCl(g)k1⇌k−12NO(g)+Cl2(g)k1=7.8×10−2L/mols and k−1=4.7×102L2/mol2sA sample of NOCl is placed in a container and heated to 473 K.When the system comes to equilibrium, [NOCl] is found...
- Q how does the reactivity of aluminum foil and aluminum sheetdiffer with (water, HCL and acetic acid)?
- Q 1.Define facilitated diffusion.Compare and contrast diffusion and facilitated diffusion.a.Give an example of a molecule thatcrosses the membrane using this mechanism.
- Q You are given 1 liter of each of thefollowing solutions: 1M HCl, 1M NaOH, 1M NH3 , 1MHC2H3O2 , 1MNH4Cl,1MNaC2H3O2a) Describe 4 different methods forpreparing a buffer solutionb) Describe how...
- Q Determine the theoretical oxygen demand for the followingsolutions:(a) 200 mg/L of acetic acid, CH3COOH(b) 40 mg/L of ethanol. C2H5OH(c) 64 mg/L of sucrose,C2H12O6.All reactions are of the form: CH3COOH +O2...
- Q Calculate the concentrations of all species present (H2CO3,HCO−3, CO2−3, H3O+ and OH−) in 0.017 M H2CO3. I already found thepH to be 4.07. H2CO3 (Ka1=4.3×10−7;Ka2=5.6×10−11).
- Q A materials scientist has created an alloy containing aluminum,copper, and zinc, and wants to determine the percent composition ofthe alloy. The scientist takes a 11.470 g sample of the alloy...
- Q A materials scientist has created an alloy containing aluminum,copper, and zinc, and wants to determine the percent composition ofthe alloy. The scientist takes a 11.470 g sample of the alloy...
- Q What is the hydroxide-ion concentration in a 0.22 M solution ofNa2CO3? For carbonic acid, Ka1 = 4.2  10–7 and Ka2 = 4.8 10–11
- Q 0.950 L of 0.420 M H2SO4 is mixed with 0.900 L of 0.280 M KOH.What concentration of sulfuric acid remains afterneutralization?
- Q The pKa of hypochlorous acid is 7.530. A 57.0 mL solution of0.108 M sodium hypochlorite (NaOCl) is titrated with 0.339 M HCl.Calculate the pH of the solutionA) after the addition...
- Q 2 SO2(g) + O2(g) --> 2 SO3(g)Properties at 25 degrees CSubstance.........delta G standard (kJ/mol)O2(g).................... 0SO3(g).................. -371.0SO2(g).................. -300.11. Calculate the Free Energy delta G standard at roomtemperature (25 degrees C). Determine...
- Q What is the redox of:ClO- (aq) + IO3- (aq) →ClO3- (aq) + I2 (s) [A]
- Q 1) what properties of the atmosphere make it particularlysuspectible to small amounts of contaminats?2) Write the apprioprate chemical equations that governs theconcentration of NO in the atmosphere if equilibrum were...
- Q What is the pH electrode response time, if the response time isconsidered to be 90% of the total signal change? Discuss
- Q A hypothetical element consists of two isotopes of masses 70.95amu and 72.95 amu with abundances of 30.9% and 69.1%, respectively.What is the average atomic mass of this element?
- Q The fizz produced when an Alka-Seltzer® tablet is dissolved inwater is due to the reaction between sodium bicarbonate (NaHCO3)and citric acid (H3C6H5O7):3NaHCO3(aq)+H3C6H5O7(aq)→3CO2(g)+3H2O(l)+Na3C6H5O7(aq) In a certainexperiment 1.25 g of sodium bicarbonate...
- Q I was wondering if I was doing a conversion right. I am supposedto take aqueous HNO3 with a density of 1.42 g/mL and a mass percentof solution of 70% and...
- Q Be sure to answer all parts. Calcium dihydrogen phosphate,Ca(H2PO4)2, and sodium hydrogen carbonate, NaHCO3, are ingredientsof baking powder that react with each other to produce CO2, whichcauses dough or batter...
- Q How many grams of sodium acetate should be added into atwo-liters buffer solution already containing 1 mole of acetic acidso as to prepare the solution with a final pH value...
- Q Consider the reaction: 2N2O(g) ---> 2N2(g) + O2(g)A. Express the rate of reaction in terms of the change inconcentration of each of the reactants and products.B. In the first 15.0s...
- Q From the given data, use a graphical method to determine theorder and rate constant of the following reaction: 2X ⟶ Y + ZTime (s) [5.0] [10.0] [15.0] [20.0] [25.0] [...
- Q A 44.7 mL sample of a 0.280 M solution of NaCN is titrated by0.220 M HCl. Kb for CN- is 2.0×10-5. Calculate the pH of thesolution:(a) prior to the start...
- Q QUESTION #1:Carbon monoxide and chlorine gas react to form phosgene:CO(g)+Cl2(g)⇌COCl2(g) Kp = 3.10 at 700 KIf a reaction mixture initially contains 321 torr of CO and 157torr of Cl2, what...
- Q A buffer is constructed by dissolving 2.05 grams of sodiumbenzoate (144.11 g/mol) and 2.47 grams of benzoic acid (122.12g/mol Ka = 6.50 x 10^-5) in 150.0 mL of distilledwater.  The solution...
- Q Menthol is a crystalline substance with a peppermint taste andodor. When 0.461 g of menthol is dissolved in 25.0 g ofcyclohexane, the freezing point of the solution is lowered by...
- Q Explain thehydrophobic effect. Why do we refer to the hydrophobic effect, andnot the hydrophobic bond?
- Q Phosphorus pentachloride decomposes according to the chemicalequationPCl5 <-----> PCl3 + Cl2Kc=1.80 at 250 °CA 0.135 mol sample of PCl5(g) is injected into an empty 2.15 Lreaction vessel held at 250...
- Q 1 - For the insoluble salt lead (ii) phosphatePb3(PO4)2, the solubility product,Ksp is 3.10x10-44a- Write the chemical equation andsolubility product expression forPb3(PO4)2b- Determine the molar solubility (M) ofPb3(PO4)2c- Identify wheather...
- Q Be sure to answer all parts. Phosgene (COCl2) is a toxicsubstance that forms readily from carbon monoxide and chlorine atelevated temperatures: CO(g) + Cl2(g) ⇌ COCl2(g) If 0.470 mol ofeach...
- Q Be sure to answer all parts. The water-gas shift reaction playsa central role in the chemical methods for obtaining cleaner fuelsfrom coal: CO(g) + H2O(g) ⇌ CO2(g) + H2(g) A...
- Q Phosphorus pentachloride decomposes according to the chemicalequation. A 0.135 mol sample of PCl5(g) is injected into an empty2.15 L reaction vessel held at 250 °C. Calculate the concentrationsof PCl5(g) and...
- Q Tartaric acid (“H2Tartâ€, M.W. = 176.13) is a diproticacid that is important in food preparation. (See McMurray & FayAppendix C for its Ka values.) A solution of tartaric acid isproduced...
- Q The reversible chemical reaction A+B⇌C+D has the followingequilibrium constant: Kc=[C][D]/[A][B]=5.4PART A:Initially, only A and B are present, each at 2.00 M .What is the final concentration of A once equilibrium...
- Q Calculate the standard deviation of the following set ofmeasured values:3.15,3.21,3.18,3.30,3.25,3.13,3.24,3.41,3.13,3.42,3.19I calculated it but my answer was incorrect. Can you please dothis problem and show the work step by step. I...
- Q Calculate the isoelectric point of the following amino acid –You must show your work! pKa of the following groups α-COOH has2.09 α-NH3 has 9.82 R group has 3.86 Aspartate
- Q The spherical volume of a H2O molecule is 0.00818 nm3 (inreality, this is a very close approximation of the volume of a H2Omolecule). How long a \"chain\" would a 0.65...
- Q Please explain this thermodynamics answer to the question.Q: What is the requirement for a single phase system to bestable with respect to phase separation?A: No combination of separated phases has...
- Q Part A: How acidic would the external pH need to become in orderto make it possible to synthesize one ATP molecule from the energydelivered when one proton enters the mitochondrial...
- Q Briefly explain the principle of SDS-polyacrylamide gelelectrophoresis. What is the purpose of the SDS? Which proteinsmidrate slowest by SDS-PAGE?
- Q 1. The glassware that is to be used for a Grignard reaction iswashed with water and acetone, and dried thoroughly before thereaction is to be performed. Select the most likely...
- Q 6. During the synthesis of a Grignard reagent in diethyl ethersolvent, bubbles are observed on the surface of the magnesium.Select the correct identity of the bubbles.a. The bubbles are gaseous...
- Q Inthe acetyl ferrocene NMR spectrum, how could you tell which peak(s)belong to the acetylated ring, and which peaks belong to thenon-acetylated ring?In the diacetylferrocene NMR spectrum, how could you predictwhich...
- Q A 2.500×10−2M solution of NaCl in water is at 20.0∘C. Thesample was created by dissolving a sample of NaCl in water and thenbringing the volume up to 1.000 L. It...
- Q Consider the structural changes that occur in the followingmolecules. BH3, CH4, NH3, H2O, HFa. according to Lewis and VSEPR theory, why doe these changedoccur?b. what are the ideal bond angles...
- Q Two aqueous hydrogen bromide solutions containing 12.0 wt% HBr(SG = 1.1377) and 30.0 wt% HBr (SG = 1.2552) are mixed to form a4.27 molar HBr solution (SG = 1.2340)1.What feed...
- Q For a sample containing both protein and nucleic acid, theabsorbance measured at a particular wavelength will be the sum ofcontributions from both types of molecule. Using the protein andnucleic acid...
- Q Specify reagents suitable for converting 3-ethyl-2-pentenetoeach of the following:a) 2,3- Dibromo-3-ethylpentaneb) 3-Chloro-3-ethylpentanec) 2-Bromo-3-ethylpentaned) 3-Ethyl-3- pentanole) 3-Ethyl-2-pentanolf) 2,3-Epoxy-3-ethylpentaneg) 3-Ethylpentane
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