Answers created by Truong-Son N.

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• At a total pressure of #"1 atm"#, if the mol percentages of #"CO"_2#, #"O"_2#, and #"N"_2# are #5%#, #15%#, and #80%# respectively, what are the partial pressures?
  
• If equal mols of #"N"_2# and #"Ar"# are in the same container with a total pressure of #"10 atm"#, #(A)# what are their partial pressures? #(B)# what is the effusion speed of #"H"_2# if that of #"He"# is #"600 m/s"# at a certain temperature?
  
• What are the first excited states of #"Mg"#, #"Al"#, #"Si"#, #"P"#, #"S"#, and #"Cl"#?
  
• #lim_(n->oo)sum_(k=1)^n e^(-k)#?
  
• Calculate the ratio of the average kinetic energies of #"8 g"# #"H"_2# compared to #"8 g"# of #"O"_2# at #27^@ "C"#?
  
• What is the difference between ideal gas equation and combined gas equation? Thank you
  
• What textbooks or review material would you recommend to study with for a major in Chemistry?
  
• Electronic configuration of Aluminum in excited state?
  
• Question #562d1
  
• How are analyte gases ionized in mass spectroscopy? What happens afterwards?
  
• What color is permanganate ion?
  
• Show that #(sinx)/(1 - cos2x) + (cosx)/(1 + cos2x) = (sinx+cosx)/(sin2x)#?
  
• Question #f2c09
  
• What is the wavelength of an electron travelling at 5x10^5 m/s?
  
• What is the maximum number of f orbitals in any single energy level in an atom?
  
• Why is phenylamine a weak base?
  
• If 10 mol of #CaC_2# reacts with #H_2O#, how many moles of #C_2H_2# will be produced?
  
• When the nonvolatile solute #B# is added into volatile solvent #A# in a #2:5# mol ratio, the vapor pressure of #A# drops to #"250 torr"#. What will the vapor pressure of #A# above the solution be if #B# is added to #A# at a #3:5# mol ratio instead?
  
• How many mols are there of methanol and ethanol above the solution if the partial vapor pressures of methanol and ethanol are #"2.619 kPa"# and #"4.556 kPa"# respectively?
  
• A general rule of thumb is that a reaction #"10 K"# higher should be twice as fast. Predict how much faster a reaction is when the temperature is changed from #10^@"C"# to #100^@ "C"#?
  
• Gold is a very unreactive element. It only bonds with strong chemicals. As Gold has a single outer S shell electron it should be reactive. Why isn't it?
  
• Does adding a nonvolatile solute to a liquid tend to increase or to decrease its vapor pressure?
  
• What is the osmotic pressure for #"1.95 g"# of sucrose dissolved in #"150 mL"# solution at #25^@ "C"#? #"FW"# #=# #"342.2965 g/mol"#
  
• If benzene and toluene have pure vapor pressures of #"700 torr"# and #"600 torr"# respectively at a certain temperature, then upon mixing equal mols of both together, what is the mol fraction of benzene above the solution phase?
  
• Question #ab304
  
• What does it mean when a substance has a pH greater than 7?
  
• What does it mean that a substance absorbs at #lambda_max#? How is absorbance related to concentration?
  
• Question #b158f
  
• Is it possible for two different substances to contain the same number of protons but different atomic numbers?
  
• How do you determine which orbitals are used in hybridization?
  
• How would you differentiate between relative atomic mass and relative molar mass?
  
• Which of these is equal to #"1 J"#? Is it #"kg"cdot"m/s"^2#???
  
• Why isn't allene planar?
  
• Question #6d808
  
• How do you integrate #int cos(lnx)# by integration by parts method?
  
• What are the total enthalpy changes for each of the following oxidation or reduction processes?
  
• What contributes to the wall of an orbit?
  
• What is the activity of pure water?
  
• Which of the following can hydrogen-bond with itself?
  
• Why is this redox reaction not balanced? Please balance it. #"H"_2"SO"_4(aq) + "K"_2"Cr"_2"O"_7(aq) + "SO"_2(g) -> "Cr"_2"SO"_4(aq) + "H"_2"O"(l) + "K"_2"SO"(aq)#
  
• Help with these 4 questions?!
  
• What does the Arrhenius equation calculate?
  
• What is the difference between #E# and #E^@# in electrochemistry?
  
• What are the units of the rate constant, k, for the decomposition of #H_2O_2#(aq)?
  
• Find the matrix X such that XA=B ..?
  
• What is the highest number of covalent bonds observed?
  
• Which of the following is true about entropy?
  
• Does any one know what the random errors are in enthalpy of combustion of alcohols experiment? like methanol, ethanol, etc.
  
• What is the derivative of # int_x^(x^2) t^3 \ dt # wrt #x#?
  
• How many electrons have quantum numbers #(n,m_s) = (3,-1/2)#?
  
• If the units of a gas-phase rate constant are #"atm"^(-1)cdot"s"^(-1)#, then what is the order of the overall reaction?
  
• Se #(dy)/(dx) = x^2 - 2x - 4# com a condição inicial #y(3) = -6#, resolva para #y#?
  
• How can I determine the color of iodide in a solution containing silver cation?
  
• Question #9a43b
  
• What is the meaning of bond energy? Bond length?
  
• Why does water not fall out of a straw when it is closed on one end?
  
• Where does the energy come from to cause electronic transitions?
  
• What is #lim_(x->oo) (1+x)^(1//x)#?
  
• Let r=r(theta), a<=theta<=b, be a curve C given in polar coordinates. Let f(x,y) be a function. Can you derive the formula for the ∫fds over C in terms of theta then use your formula to find the arc-length of the cardiod r = 1+costheta?
  
• What is the integral of #(lnsqrtx)/x#?
  
• If a gas begins at #"600 cm"^3# and its pressure increases by #"30 kPa"# from #"100 kPa"# of pressure in one minute, what is the average rate of change in volume per unit time?
  
• How do I find the order for each reactant?
  
• What is the density of a mixture of methane, ethane, propane, and n-butane at #130^@ "C"# and #"1 atm"#? What is its specific gravity?
  
• How do you find the density of a solution if you know the identity of the solute and solvent, the amount that you combine of each, and their individual densities?
  
• An electron in a mercury atom jumps from level #a# to level #g# by absorbing a single photon. How do you determine the energy of the photon in joules?
  
• How does water boil in a pot without a lid?
  
• What is the purpose of a Lewis structure? What do the chemical symbol and lines in these structures represent?
  
• If an aqueous solution starts at #"36 g/L"# and #"4.98 bar"#, what is the new concentration in #"g/L"# needed to accomplish an osmotic pressure of #"1.52 bar"#?
  
• Derive elastic strain energy?
  
• A projectile is shot from the ground at an angle of #( pi)/3 # and a speed of #15 m/s#. Factoring in both horizontal and vertical movement, what will the projectile's distance from the starting point be when it reaches its maximum height?
  
• How much heat is needed to vaporize #"25.0 mL"# of water at its normal boiling point? #DeltaH_(vap) = "40.65 kJ/mol"#.
  
• How many spherical nodes are in a #3d_(xy)# orbital?
  
• How do you graph the equation #y=4x-2#?
  
• What is the isotope symbol for oxygen-18?
  
• If #"0.64 g"# of napthalene (#M = "128.1705 g/mol"#) is dissolved in #"100 g"# a certain solvent (#T_f^"*" = 6^@ "C"#), whose #K_f = 20^@ "C"cdot"kg/mol"#, what is the new freezing point of the solvent?
  
• What is the position of electrons inside the orbitals such as s-,p- etc?? I mean I know that they are in these spherical(s-orbital) and dumb-bell shaped(p-) but where do they actually lie?
  
• How long can a hypothesis be?
  
• What is the general formula that represents the compound #CH_3CH_2C CH#?
  
• What is the first-order half-life for #"0.50 M"# of a substance whose radioactive decay has a rate constant of #0.69 xx 10^(-2) "min"^(-1)#?
  
• Question #0799c
  
• What is the integral of #(x+1)/(x(x^2+x-6))#?
  
• Question #9f75a
  
• How do you find the derivative of #tan^4 (x)#?
  
• How do you write a net ionic equation? Show an example please.
  
• What causes gas molecules to spread through air?
  
• Im having trouble understanding what the question is asking?
  
• A sample of hydrogen gas is collected over water at 25°C. The total pressure of the hydrogen and water vapor is 116.0 kPa. The partial pressure of water vapor at this temperature is 3.2 kPa. What is the pressure of the hydrogen gas alone?
  
• What new pressure must be overcome for water to boil at #40^@ "C"#? #DeltabarH_(vap) = "40.65 kJ/mol"# for water at #25^@ "C"# and #"1 atm"#.
  
• Is ΔH=mCΔT and q=mCΔT the same thing? If so, which is more scientific?
  
• A 1/8 dilution of the stock solution is made followed by a 1/6 dilution. What is the final dilution?
  
• If the solubility of sugar (sucrose) in water is 2.0 g/mL at room temperature, what is the maximum amount of sugar that will dissolve in 100.0 mL water, 355 mL (12 oz) water and 946 mL (1 qt) water?
  
• It was found that in a diving gas mixture for a certain altitude, the total predicted pressure is #"8.38 atm"#. If the partial pressure of oxygen gas must be #"0.21 atm"# underwater, what must the mol fraction be of oxygen gas?
  
• How would you draw and label energy diagrams that depict the following reactions, and determine all remaining values? Place the reactants at energy level zero
  
• When adding base to a weak acid, does the concentration of #"HA"# have a net increase after the endpoint?
  
• How do I determine bond length(s) for a molecule?
  
• How would the equipartition theorem be used to estimate the average kinetic energy of molecules?
  
• Help me annotate my IR spectrum of 2-​Propanone, 2-​(2,​4-​dinitrophenyl)​hydrazone?
  
• When benzene vaporizes into a vacuum at #60^@ "C"# and #"1 atm"#, is it reversible or irreversible?
  
• What are the quantum numbers for last electron of cadmium?
  
• Question #1c86b
  
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