Answers created by Truong-Son N.

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• Calculate the change in freezing point for ice if the pressure changes from #"1 atm"# to #"3 atm"#?
  
• What factors should we consider when we decide what glassware to use?
  
• What is the oxidation state of cobalt in #"Na"["Co"("NH"_2)("en")("NO"_2)("S"_2"O"_3)]#?
  
• How do I calculate the pressure in #"bar"# for #"Cl"_2# if #"1.140 mols"# of it occupies #"5.025 L"# at #"244.5 K"#, using the van der Waals equation of state?
  
• A student pours #"25.00 L"# of #"0.00200 M"# iron (II) nitrate solution into the beaker labeled "cathode" and sets up an iron strip at the cathode. He then sets up another beaker labeled "anode"...?
  
• Why would fluorine have a positive oxidation state in #"HOF"# even though it is more electronegative?
  
• Why do chlorine and nitrogen follow the Aufbau principle, but copper does not?
  
• If the density of an ethylene glycol solution is #"1.0241 g/mL"#, and ethylene glycol has a molar mass of #"62.07 g/mol"#, what is its molarity? The molality is #"16.11 L"#.
  
• Provide one set of acceptable quantum numbers for each of the valence electrons in sulfur?
  
• If the density of a solution is #"5 g/L"#, what mass of the solution is #"750 mL"# in volume?
  
• Why Nacl5 is an unlikely structure?!?!
  
• What is the molality of the resultant solution when equal masses of a #"2 molal"# solution of #"NaOH"# and a #"4 molal"# solution of #"NaOH"# are combined?
  
• Is gold an element?
  
• What is the entropy of vaporization for water if the enthalpy of vaporizing #"1 mol"# of water is #"40.66 kJ/mol"# at its normal boiling point?
  
• In really simple/child-like terms, with some sophistication can someone explain orbital hybridizations and what the point of it is?
  
• What is the rate law for the following reaction and data?
  
• What is the molar mass of water??
  
• How many molecules of calcium are in #"463.78 g"# of calcium?
  
• Isn't ammonium chloride more electrically conductive in water than acetic acid would be, because ammonium chloride doesn't dissociate well in water and acetic acid does?
  
• What is #DeltaE# for a system that absorbs #"77.7 J"# of heat and expands from #"0.250 L"# to #"0.750 L"# against an external pressure of #"1.161 atm"#?
  
• Energy change is the sum of heat and work: ΔE = q + w. Work is calculated by: w = -PΔV What is the change in energy (in joules) if a reaction absorbs 40.3 J of heat and increases in volume from 0.250L to 0.750L at a constant pressure of 1.056 atm?
  
• Can a #"C"-"C"# bond exist in a stable compound?
  
• Which gas is faster, #"CO"# or #"He"#?
  
• Why is a mole fraction independent of temperature?
  
• Question #bc2e5
  
• What is the de Broglie wavelength of an electron that has been accelerated through a potential of #"10 V"#?
  
• The relative molecular weight of acetic acid is 60.05 and its density is 1.049g/ml. Describe how you would prepare 1L of 2M solution of acetic acid?
  
• What are the enthalpies of fusion, melting, vaporization, and condensation of water at the corresponding phase transition temperatures?
  
• How do I know that #"NaHCO"_3(aq)# is soluble in water?
  
• Why is it not good if acid touches refractory furnace linings?
  
• Does an element with an electron configuration of #["Noble gas"]ns^2(n-1)d^8# have #10# valence electrons?
  
• If #"H"_2# and #"He"# are at #"1 atm"# and #"2 atm"# respectively, find the ratio of speeds for #"H"_2# vs. #"He"#?
  
• Which of these would neutralize the most #"HCl"#?
  
• What should the rate law be for the following reaction and mechanism? My book says the answer is #k[A]^(1//2)[B]# but wouldn't it be #A_2#?
  
• How long does it take a radioactive element to decay to #10%# of its original quantity in a first-order process if its half-life is #"43.80 s"#?
  
• At #2^@ "C"#, a certain reaction has a rate constant of #4.60 xx 10^(-6) "s"^(-1)#. If the activation energy is #"108 kJ/mol"#, at what temperature does this reaction have a rate constant of #"0.58 s"^(-1)#?
  
• For the overall reaction #2X_2Y_2 + Z_2 -> 2X_2Y_2Z#, which of the following mechanisms is consistent with the rate law #r(t) = k[X_2Y_2][Z_2]#?
  
• What is the activation energy for a reaction with a frequency factor of #1.2 xx 10^13 "s"^(-1)# and a rate constant of #5.9 xx 10^(-2) "s"^(-1)# at #31.00^@ "C"#?
  
• Question #2028e
  
• What hybridization is generally utilized by the central atom in a square planar molecule?
  
• How do you name #"H"_3"C"{"C"("CH"_3)_2}_2("CH"_2)_2"CH"_3# and #"H"_3"C""CH"_2("CH""CH"_2"CH"_3)("CH"_2)_2"CH"("CH"_3)_2#?
  
• The reaction #2"Ce"^(4+)(aq) + "Tl"^(+)(aq) -> 2"Ce"^(3+)(aq) + "Tl"^(3+)(aq)# is slow; write the rate law?
  
• Why is the atomic mass unit (amu), rather than the gram, used to express atomic mass?
  
• What is the definition of standard temperature and pressure (STP)?
  
• If an aqueous solution of #"Mg"("OH")_2# had a #"pH"# of #10.52# at #25^@ "C"#, what is the solubility of #"Mg"^(2+)#?
  
• How to calculate oxidation number of Iron in ferriferrocyanide Fe4[Fe(CN)6]3 ?
  
• What is the value of the rate constant for this reaction at this temperature?
  
• Plot the density on the vertical axis and the mass % ethylene glycol on the horizontal axis and determine the % ethylene glycol content of an ethylene glycol-water mixture that has a density of 1.030 g/mL. Could you post a picture of the chart?
  
• Question #a165a
  
• Why is this name not correct? #"7-ethyl-3,4,4,7-tetramethylheptane"#; what should it be?
  
• Is it true that rate constants are independent of concentration but dependent on temperature? Can you prove it?
  
• What is constant about the rate constant? Does it change with temperature?
  
• If numerically, the momentum and position uncertainties are equal, what is the uncertainty in the velocity?
  
• Does it logically follow that gases compressed to higher pressures move faster?
  
• If the rate constant is #"109 s"^(-1)# at #"352 K"# and #"185 s"^(-1)# at #"426 K"#, what is the activation energy for this reaction?
  
• Question #d10dd
  
• What is the difference between bonding, nonbonding, and antibonding orbitals when it comes to bond order and Lewis structures?
  
• What is the structure of 5,5-diethyl-2,2,3-trimethylheptane?
  
• How to determine the temperature change for dissolving #"10.0 g"# of #"KClO"_4(s)# into water?
  
• If I am to write the quantum numbers for the highest energy electron in Cr, or any of the transition elements in its respective row, would n=3, l=2?
  
• How do you start from a #"70%w/w"# #"HClO"_4# solution (density is 1.67) to prepare a #10"%w/v"# solution by starting with a volume of #"5 dm"^3#? #M = 100.46#
  
• Question #243d0
  
• What is the energy of the first excited state of hydrogen atom? How high is it above the ground state if the ground state is at #-"13.61 eV"#?
  
• What happens to the momentum uncertainty as the position uncertainty approaches zero?
  
• Identify the types of bonds (dative vs. covalent) indicated in the compound shown below?
  
• Question #b14c0
  
• If I have #1254# aluminum cans, and every #22# of them weighs #"1 lb"#, how much volume in #"L"# does this set of #1254# cans occupy?
  
• Did I correctly draw 5-butyl-8-ethyl-2,2-dimethyldecane?
  
• How do you name this compound that has six carbons and two #"CH"_3# on the third carbon from the right? The rest are #"H"#'s
  
• How can you change the specific heat capacity of water?
  
• Ascorbic acid (C6H8O6) has how many acidic protons that it will lose when reacting with NaOH?
  
• How many pieces of data do you need to get the enthalpy of fusion of copper? The heat capacity of copper is #"0.385 J/g"^@ "C"#.
  
• Although the value of second ionisation potential of alkaline earth metals is higher than that of 1st ionisation potential yet these metals form #M^"+2"# ions but no #M^+# ion?
  
• What is the chemical symbol for element #E#?
  
• If plotting #ln[A]# vs. time gives a straight line, what is the order of reaction?
  
• When are the bonds of ions both covalent and ionic?
  
• What is the molar mass for a solute if #"12.0 g"# of it is dissolved in #"108 g"# of water, resulting in a vapor pressure that is #10%# lower?
  
• If I know the mass of #"8000 HCl molecules"#, could I find the mass of #"8000 chlorine atoms"#?
  
• What is the time it takes for a first-order decay to leave the reactant at #1/8# of its original concentration if the reaction's rate constant was #3.30 xx 10^(-3) "s"^(-1)#? I put in #"1680 s"# but it was incorrect.
  
• From the data, determine the rate constant for the reaction? #"CHCl"_3(g) + "Cl"_2(g) -> "CCl"_4(g) + "HCl"(g)#
  
• A plot of #ln[A]# vs. #t# for the reaction #A -> B + C# gives a straight line, with slope #-4.6 xx 10^(-3) "s"^(-1)#. Calculate the rate constant?
  
• Question #d3bab
  
• From the data, what is the rate law for the reaction? #"CHCl"_3(g) + "Cl"_2(g) -> "CCl"_4(g) + "HCl"(g)#
  
• Find the following for the reaction #"NO"(g) + "O"_3(g) -> "NO"_2(g) + "O"_2(g)#?
  
• What are the units of the rate constant in a zero order reaction?
  
• At what temperature is the Fahrenheit value numerically equal to the Celsius value?
  
• Why does the #ns# orbital go before the #(n-1)d# orbital when writing transition metal electron configurations?
  
• What would a six coordinate metal-ligand complex structure look like?
  
• For an uncatalyzed reaction, the activation energy was #"76 kJ/mol"#. Upon being catalyzed, the activation energy was lowered by #"20 kJ/mol"#. How much faster is the reaction?
  
• Can lead become isoelectronic with xenon? How many electrons would it have to lose?
  
• How many electrons can be spin-up in all the orbitals in the #n = 4# shell?
  
• HCl is a polar molecule, how come the intermolecular forces among its molecules consist of London dispersion force besides dipole dipole attraction ? Thank for answering.
  
• Are there any polar halogens?
  
• Shouldn't electron affinity increase going down the noble gases because they have more electrons? Why does it decrease?
  
• Why is pressure always negative in the formula #w = -P DeltaV#?
  
• What’s the difference between a p-orbital of the second shell and a p-orbital of the third shell? Thank you!
  
• If #"68.9 mg"# of safrole, #("C"_x"H"_y"O"_z)_n# combusts, and #"187 mg"# of #"CO"_2# and #"38.3 mg"# of #"H"_2"O"# form, what is the empirical formula of the hydrocarbon? If its molar mass is #"162 g/mol"#, what is the molecular formula?
  
• How do you balance the complete combustion given by #"C"_4"H"_10 + "O"_2 -> "CO"_2 + "H"_2"O"#? All phases are gases here.
  
• How much heat at constant volume and at constant pressure is needed to heat #"18 g"# of #"O"_2# from #40^@ "C"# to #100^@ "C"#? #C_V = "12.6 J/mol"cdot"K"#, #C_P = "20.85 J/mol"cdot"K"#.
  
• The hydrogenic atomic orbitals in different coordinate systems are what? Aren't they easier to work with in Cartesian?
  
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