Chemistry question and answers for October 06, 2023
- Q Phosphorus pentachloride decomposes according to the chemicalequation PCL5(g)<--->PCl3(g)+Cl2(g). Kc=1.80 at 250 C. A0.220 mol sample of PCl5(g) is injected into an empty 3.00 Lreaction vessel held at 250 �C. Calculate...
- Q A. You mix a 125.5 mL sample of asolution that is 0.0111 M in NiCl2 with a 183.0 mL sample of asolution that is 0.225 M in NH3After the solution...
- Q 23.balance Al2O3(s)+NaOH(i)+Hf(g)--> Na3AlF6+H2O(g)a. If 11.1 kilograms of Al2O3(s), 59.4 kilograms of NaOH(l), and59.4 kilograms of HF(g) react completely, how b. many kilograms ofcryolite will be produced?c. Which reactants will be...
- Q Classify each statement about effective nuclear charge, Zeff, astrue or false.-Effective nuclear charge increases from left to right across aperiod on the periodic table-Across a period, as Zeff increases, atomic...
- Q A beaker with 125 mL of an acetic acid buffer with a pH of 5.00is sitting on a bench top. The total molarity of acid and conjugatebase in this buffer...
- Q If28.45 grams of ammonia are utilized for its synthesis, how manygrams of hydrogen are needed?2NO(g)+5H2(g)------>2NH3(g)+2H2O(g)
- Q A 0.4672 g sample of pewter (containing tin, lead, copper, andzinc) was dissolved in acid. The precipitate SnO2
- Q In a particular redoxreaction, NO2
- Q What is the relationship between the percent of oxygen in a fueland the amount of energy avaliable per mole of fuel?
- Q Lithium Nitrogen reacts to form Li3N. A 4.0g sample of lithiumis reacted with 2.5g of nitrogen. What weight of what substanceremains unreacted?
- Q Given the following thermodynamic reactions: CaO (s) + Cl2 (g)---> CaOCl2 delta H° = -110.9 KJ/ H20 (l) + CaOCl2 (s) + NaBr(s) ---> 2NaCl (s) + Ca(OH)2 (s) +...
- Q 3.Phosphate-buffered saline (PBS) is a buffer solution commonlyused in biological research. Most formulations contain a mixture ofKCl and NaCl buffered to a pH of 7.40 using phosphate-containingcompounds.a.The following reagents are...
- Q Thereactivity of a combination of monomers depends a great deal on thenature of the polymerizing center. For example, the reactivityratios of butadiene (1) and styrene (2) are quite different in...
- Q One millimole of Ni(NO3)2 dissolves in 210mL of a solution thatis .500M in NH3.(a) What is the initial concentration of Ni(NO3)2 in thesolution?------> The answer to (a) is .00476 M....
- Q Oxalic acid, H2C2O4 has acid dissociation constants Ka1 = 5.9 �10^2 and Ka2 = 6.4 � 10^5. What is the pH after 20.00 mL of 0.0500M NaOH is added to...
- Q Assuming that the smallest measurable wavelength in anexperiment is 0.570 fm , what is the maximum mass of an objecttraveling at 745 m â‹… s-1 for which the de Brogliewavelength...
- Q A 2.100×10−2 M solution of glycerol (C3H8O3) in water is at20.0∘C. The sample was created by dissolving a sample of C3H8O3 inwater and then bringing the volume up to 1.000...
- Q A gaseous mixture consists of 76.0 mole percentN2 and 24.0 mole percent O2(the approximate composition of air). Suppose water is saturatedwith the gas mixture at 25°C and 1.00 atm total...
- Q A buffer with a pH of 3.90 contains 0.15 M of sodium benzoateand 0.30 M of benzoic acid. What is the concentration of [H ] inthe solution after the addition...
- Q Measuring RadiationPart AAt a distance of 40 ft , an ionizing radiation source delivers7.0 rem of radiation. How close could you get to the source andstill have no biological effects?Express...
- Q The following enthalpy and entropy changes are known for thereactions shown at 298 K.ReactionCu(s) + 2H+(aq) <=> Cu2+(aq) +H2(g)Zn(s) + 2H+(aq) <=> Zn2+(aq) +H2(g)delta H65 kJ/mol-153 kJ/moldelta S-2.1 J/mol K-23.1...
- Q A holding tank with capacity 5000 litres initially contains 1500litres of 25 mM NaCl solution. a) What is the final concentrationof NaCl (expressed in mM) if an additional 3000 litres...
- Q The generic reaction2A?Bhas the following rate laws:forward reaction:reversereaction:rate=kf[A]2rate=kr[B]where kf is the rate constant for the forward reactionand kr is the rate constant for the reverse reaction. Atequilibrium, the two rates...
- Q Calculate the pH at the equivalence point in titrating 0.034 Msolutions of each of the following with 0.093 M NaOH. (a) periodicacid (HIO4) pH = (b) hydrocyanic acid (HCN), Ka...
- Q In organic chemistry lab we just completled a \"LidocaineSynthesis\". I have some questions to clarify before we take the inclass exam.1. Based on apperence and melting point; how can we...
- Q 5. A sample of N2 gas at 298 K and 1 atm. The diameter of N2molecule is d = 3.6 × 10-10 m. (1) Calculate the collisions persecond that one...
- Q Electrochemistry is the study of the conversion between chemicaland electrical energy. Describe how oxidation-reduction reactionsare used to make a battery, converting the chemical energy from thereactions to electrical energy.
- Q 1. Farmers who raise cotton onve used arsenic acid, H3AsO4, as adefoliant at harvest time. Arsenic acid is a polyprotic acid withK1 = 2.5 * 10-14, K2 = 5.6 *...
- Q Aspirin can be prepared from salicylic acid ( C 7 H 6 O 3 ),which has a molar mass of 138.12 g/mol, and acetic anhydride ( C 4H 6 O...
- Q Consider the hypothetical heteronuclear diatomic molecule XYwhere Y is more electronegative than X. Using only the p orbitalsfrom each atom, construct a molecular orbital diagram. For eachunique type of bond...
- Q The activation energy of an uncatalyzed reaction is 70.0 kJ/mol.When a catalyst is added, the activation energy (at 20.0 C) is 42.0kJ/mol. Theoretically, to what temperature (C) would one have...
- Q a. Give one safety hazard when using the Bunsen burnerand one precautionary to avoid this hazard.b. What safety measures do you need to practice when using the ovento dry the...
- Q To prevent brain damage, a standard procedure is to lower thebody temperature of someone who has been resuscitated aftersuffering cardiac arrest. What is the physiochemical basis for thisprocedure?
- Q The pH of an aqueous solution of 0.572 Mcaffeine (a weak base with the formulaC8H10N4O2)is:
- Q Two thousand (2,000) pigs in the growing-finishing stage (60 kg)are housed at a temperature (Ti) of 15 C. The indoorrelative humidity (RHi) should not exceed 70%. Theoutdoor air conditions are...
- Q Given these reactions,X(s) + 1/2 O2(g) -----> XO(s) Delta H = -699.3kJ/molXCO3(s) -------> XO(s) + CO2(g) Delta H= +328.3 kJ/molwhat is Delta Hrxn for this reaction?X(s) + 1/2 O2(g) +...
- Q What is the difference between a reversible and irreversibleprocess in chemistry?
- Q At what point(s) during the oscillation of a spring that obey'sHooke's law is the force on the mass the greatest?
- Q Calculate the equilibrium constant for the reaction betweenNi2+(aq) and Zn(s) under standard conditions at 25∘C.
- Q 4.Which reactions are redox reactions?Choose at least one answer.A. hydrochloric acidreacting with nickel metal to form hydrogen gas and aqueousnickel(II) chlorideB. sodium bromidereacting with chlorine to form sodium chloride and...
- Q When tert-butanol is placed in the presence of excess equimolaramounts of chloride and bromide ions in aqueous acid experimentaldata indicates 45% tert-butyl chloride and 55% tert-butyl bromideis obtained. On the...
- Q Carbonic acid, H2CO3, is a weak diproticacid. In a 0.1 M solution of the acid, which of thefollowing species is present in the largest amount?H2CO3.H3O+HCO3
- Q A .053M solution of a weak base has a pH of 9.87. What is the Kbof this weak monprotic acid?
- Q The formation constant* of [M(CN)6]4– is 2.50 × 1017, where M isa generic metal. A 0.130-mole quantity of M(NO3)2 is added to aliter of 1.150 M NaCN solution. What is...
- Q 1. Add 0.5 mL of 0.10 M NiCl2 solution to each of 7 test tubesusing dropper provided. Label these tubes 1 through 7. 2. Add thefollowing to the respective tubes...
- Q The balanced equation for the neutralization reaction of aqueousH2SO4 with aqueous KOH is shown.H2SO4(aq)====>2H2O(l)+K2SO4(aq)Whatvolume of 0.370 M KOH is needed to react completely with 15.5 mL of0.135 M H2SO4? Assume...
- Q Calculate the pH when 2.63 g of C6H5COONais added to 41 mL of 0.50 M benzoic acid,C6H5COOH. Ignore any changes in volume. TheKa value for C6H5COOH is 6.5 x10-5
- Q This question related to Diels-Alder Reaction of Anthracene andMaleic Anyhydride.1. Show the product of the reaction of water with the anhydrideproduct2. The procedure warns against adding a lot of xylene...
- Q If you eat a 48 g serving rice every fourth day and you weigh 75kg, what is your dose of inorganic arsenic (in µg per kg bodyweight per day) if...
- Q Calculate the molar solubility of Ca(IO3)2ina) 0.060 M Ca(NO3)2b) 0.060 M NaIO3
- Q The following picture represents a sample of gas at a pressureof 1 atm, a volume of 1 L, and a temperature of 25 ?CWhat would happen to the pressure if...
- Q 1a- Discuss the vaporization of water in standard condition at298 K in term of: -A exothermicity and endothermicity -Achange ofentropy of the system and the surrounding - A spontaneity of...
- Q a cube of osmium metal 1.500 cm on one of its sides. It also hasthe mass of 76.31g at 25°C please help me solve this problem byshowing your work so...
- Q How many moles of NH4Cl must be added to 100 mL of0.1 M NH4OH solution to prevent precipitationof Mn(OH)2 when this solution is added to 100 mL of a0.002 M...
- Q Please solveWhat is the percent dissociation of HNO2 when 0.074 gof sodium nitrite is added to 115.0 mL of a 0.068 MHNO2 solution? Ka forHNO2 is 4.0 × 10–4. (4%)
- Q 7.0 E 2 of a 50:50 mixture on n-propanol (CH3CH2CH2OH) andn-butanol (CH3CH2CH2CH2OH) are discharged into a body of watercontaining 1.0 E 10 L of H2O. What is the BOD of...
- Q Arrange the following ions in order of increasing ionicradius:1.) potassium ion, calcium ion, sulfide ion, chloride ion2.)barium ion, iodide ion,telluride ion, cesium ion
- Q Balance the following oxidation–reduction equation. Thereactions occur in a basic aqueous solution.Cd2++ H  2S→  Cd + S  8S2- + F2 →SO42- + F-Cr + NO3- →Cr(OH)4- +NH3MnO4- +C2O42- →MnO2 + CO2
- Q a)What is the pH of a solution prepared by adding 25.00 ml of0.0993 M sodium hydroxide to 30.00 mL of 0.0553 M acetic acid?There will be a reaction. What two...
- Q The concept of energy charge is a very useful way to think abouthow ATP levels control pathway activity. Discuss the role of ATP inthe glycolytic pathway (between glucose and pyruvate...
- Q Write the Total and Net Ionic Equation for the following; makesure to include state symbolsCalcium plus a solution of hydrochloric acidChlorine plus a solution of potassium bromideA solution of ammonium...
- Q calculate [OH−] and pH for each of the following solutions.1. 6.0×10−2 M NaBrO2. 7.7×10−2 M NaHS
- Q Calculate the standard potential, E°, for this reaction from itsequilibrium constant at 298 K. X(s) + Y^2+(aq) ⇌ X^2+(aq) + Y(s)   K= 1.43 x 10^-6    E^o = ?V
- Q Consider the titration of a 25.0 −mL sample of 0.100 M HC2H3O2with 0.120 M NaOH. Determine each of the following.the initial pHExpress your answer using two decimal places.pH =2.87B)Part Bthe...
- Q Consider the equilibrium reactionCO(g)+H2O(g)⇋CO2(g)+H2(g)Determine how each change in the left-hand column will stressthe system and in which direction the equilibrium reaction willshift in response.Drag the appropriate labels to their respective...
- Q A 110.0 −mL sample of a solution that is 2.9×10−3 M in AgNO3 ismixed with a 230.0 −mL sample of a solution that is 0.11 M in NaCN.After the solution...
- Q 3.The partition coefficient ofCompound A is 7.5 in dichloromethane (a.k.a. methylene chloride)with respect to water.If 5 grams of Compound A were dissolved in 100 mL of water, howmuch of Compound...
- Q which chemicals that are green (not likely to harm theenvionment) and two that are not green?N-ethylsaccharin, O-ethylsaccharin, ethyl iodide, saccharin,N-sodium saccharin, O-sodium saccharin, NaOH, DMF
- Q What happens to a halogenation reaction of a Alkene or Alkyne whenthe reaction is cold?
- Q 1) A buffer solution contains 0.356 Mammonium chloride and0.396 M ammonia.If 0.0550 moles of hydroiodic acid are added to 250 mlof this buffer, what is the pH of the resulting...
- Q If 5.00 g of copper (Csh = 0.390 J/g°C), 3.00 g of iron (Csh =0.450 J/g°C), and 4.00 g of zinc (Csh =0.380 J/g°C) at 60 °C are dropped into...
- Q Two students beging by mixing 5.0ml of a 3.1M solution of methylorange and 5.0 ml of a 3.1 M solution of methyl red in anErlenmyrer flask. How many drops of...
- Q Aballoon filled with 6.50 L He rises from sea level to a heightwhere the pressure is 700 mm Hg. Would the volume of the gas in theballoon be greater than,...
- Q Draw a structural formula fortrans-2-chlorocyclopentanol.Draw a structural formula for3-methyl-1-pentanol.Draw a structural formula fortrans-2-bromocyclobutanol.
- Q What is buoyancy and how does it cause errors in mass measurementwith electronic balance?
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