Answers created by Truong-Son N.

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• How do you evaluate #lim_(x->0^(-)) e^x/(1+lnx)#?
  
• What are the extrema and saddle points of #f(x,y) = x^2+xy+y^2+y#?
  
• How can you find oxidation numbers of transition metals?
  
• What is the molecular electron configuration of #"O"_2#?
  
• Is matrix subtraction commutative?
  
• What does the graph #r = sqrt(sintheta)# look like in plane polar coordinates? How do you graph it?
  
• Question #b239d
  
• What is a conical node? How can you find one?
  
• More reactive the metal, lesser the melting it has. Right?
  
• How does the bond energy for the formation of #"NaCl"(s)# take place? Please explain in steps comprehensively but concisely. Thank you in advance.
  
• How would you balance the complete combustion of acetylene by oxygen gas in a constant-pressure calorimeter?
  
• Ms. Burger has graded 45 tests. This represents 60% of her 3 math classes. How many math students does Ms. Burger teach?
  
• How do you multiply #((-2, -5, 3), (3, -1, 2), (1, 4, -2))# with #((1, 4, 3), (-3, -3, 2), (-2, -1, -2))#?
  
• What is #int 9/(x^2sqrt(4x+1))dx#?
  
• Can pressure be zero?
  
• In terms of electron affinity, can you explain this statement: "the stronger the attraction, the more energy is released"?
  
• A charge of #5 C# is at #(-6, 3 )# and a charge of #-2 C# is at #(-5 , 7 ) #. If both coordinates are in meters, what is the force between the charges?
  
• What are some examples of physical chemistry?
  
• Find the percent #"P"_2"O"_5# by mass in the fertilizer?
  
• What is the mechanism for the acid-catalyzed esterification of formic acid and 2-butanol?
  
• What is a planar molecule?
  
• How to determine functional group?
  
• Draw the lewis structure of acetaminophen and all the intermolecular forces that occur in it?
  
• How do you calculate the change in entropy for an isothermal process?
  
• What Is Z component of orbital angular momentum? How can we find the Z component? What is its importance? What does it resemble?
  
• How do you solve the system of equations #-12d - 7e = 48# and #5d + e = 3#?
  
• What will be the freezing point of a 20.0% solution of glucose, #C_6H_12O_6# in water?
  
• What is the slope of the line normal to the tangent line of #f(x) = cscx-secx # at # x= (17pi)/12 #?
  
• For the reaction #"C"(s) + "O"_2(g) -> "CO"(g)#, how many mols of #"O"_2# would be made from #"2.04 mols"# of #"C"#?
  
• Where does the positive charge come from on an atom?
  
• What does it mean if a solution is concentrated?
  
• What is the slope of the line normal to the tangent line of #f(x) = cscx-sin2x # at # x= (pi)/12 #?
  
• How do you integrate #int (4x)/sqrt(-x^2-6x+75)dx# using trigonometric substitution?
  
• MO diagram of #"B"_2"H"_6^(2-)#?
  
• Why does #"HF"# have a lower boiling point than water even though #"F"# is more electronegative than #"O"#?
  
• How do you convert Kelvin to Fahrenheit?
  
• Question #19c27
  
• If the temperature coefficient #alpha# for a certain reaction is #2.5#, then if the reaction was run at #283^@ "C"# and #293^@ "C"#, what is the activation energy in #"kJ/mol"#?
  
• Question #7a5f8
  
• What is the derivative of #f(x) = x(2-x)^2#?
  
• How do you find #dy/dx# by implicit differentiation given #e^y=x^2+y#?
  
• How much heat is required to heat ethanol from #25^@ "C"# to a gas at #78.24^@ "C"#? #C_P = "2.460 J/g"^@ "C"#, #DeltaH_(vap)^@ = "38.56 kJ/mol"#, #T_b = 78.24^@ "C"#
  
• How do you calculate the wavelength of the light emitted by a hydrogen atom during a transition of its electron from the n = 4 to the n = 1 principal energy level? Recall that for hydrogen #E_n = -2.18 xx 10^-18 J(1/n^2)#
  
• If given the following what would the reduction potential be on the new scale in which the reaction of water in base has an #E^o"_(red) = 0.000 V#?
  
• What is the free energy for the dissolution of solid sodium chloride in water at 25C?
  
• According to the Pauli exclusion principle, when can two electrons occupy the same orbital?
  
• Is an ionic bond stronger than a comparable covalent bond? If not, then why do ionic compounds typically have higher melting points than covalent compounds?
  
• What is the enthalpy of reaction in #"kJ/mol"# for when #"0.254 g"# of #"Mg"# is dropped into a coffee-cup calorimeter, if the temperature of #"200. mL"# of water rose from #25.00^@ "C"# to #32.20^@ "C"#?
  
• How did you get #9.5%# for the theoretical yield of the potato chips in the Food Calorimetry Lab? I get #11%#.
  
• What is the benefit of colder temperatures on recrystallization?
  
• The increasing order of the #"p"K_"b"# value is: 1) #"HC≡C"^"-"#; 2) #"H"^"-"#; 3) #"NH"_2^"-"#; 4) #"CH"_3^"-"#?
  
• Is the half-life of a first-order decay dependent on temperature?
  
• How do you calculate #lim x->3# of #(x^2-2x-3)/(x-3)#?
  
• How do you calculate #DeltaS_(sys)# for the isothermal expansion of 1.5 mol of an ideal gas from 20.0 L to 22.5L?
  
• Why is this reaction still not balanced? #"CaCl"_2cdot2"H"_2"O"(aq) + "K"_2"CO"_3(aq) -> "CaCO"_3(s) + 2"KCl"(aq)#
  
• Can someone help me understand orbitals??
  
• What are the hybridizations of the leftmost and rightmost carbon on propyne?
  
• Solutions of the #[V(OH_2)_6]^(3+)# ion are green and absorb light of wavelength 560 nm. What is the ligand field splitting in the complex in kJ/mol?
  
• What will be product(s) if ethylene glycol is treated with fuming sulphuric acid & heat ?
  
• How do you derive taylor polynomial for #x/(1+x)#?
  
• What is the #100#th derivative of #2e^x#?
  
• How do you find the limit of #cos(x)/(x - pi/2) # as x approaches pi/2?
  
• What is the correct name for #Li_3N#?
  
• What is a reaction with a negative #DeltaG# and occurs spontaneously?
  
• What word or two-word phrase describes the shape of the formaldehyde (#CH_2O#) molecule?
  
• Why can't I change the subscripts in a molecule when I balance a chemical reaction?
  
• Name each of the following compounds?
  
• Why do alkyl groups have lower electronegativity versus hydrogen? How does this affect the acidity or alkalinity of alcohols?
  
• Using the Schrodinger equation, what can we calculate?
  
• Given 10, 17, 24, 31, the nth term is given by 7n+3. How you know?
  
• How do you find the indefinite integral of #int sqrtx/(sqrtx-3)#?
  
• Why chelate compounds are stable than nonchelated compounds?
  
• What is bond order? How we can determine it? Please basics. Thank you so much.
  
• The Henry's law constant for methylamine (#CH_3NH_2#) is 36M/bar. What is the equilibrium vapor pressure of methylamine over a solution that is 2.23 mM #CH_3NH_2#?
  
• Why are electrons less repulsive when in a bond than when as a lone pair?
  
• Does dry ice melt or evaporate?
  
• Consider the molecule [MnX6]2+, where X is a neutral ligand. Assume that X is a strong field ligand?
  
• If you want to prepare a solution that has #"pH" = 8.51# at #25^@ "C"#, what initial concentration of #"NaF"# would you need to achieve?
  
• Can a compound only contain two different kinds of atom?
  
• Why is it incorrect to say that the boiling point of a substance is 100 C?
  
• What are the quantum numbers for atoms?
  
• If the uncertainty in the position is equal to the wavelength of an electron, how certain can we be about the velocity? Determine an expression for #v_x//Deltav_x#.
  
• If heat goes into a liquid, do I need to care about the work done on the liquid? Aren't they incompressible?
  
• How do I decide what mass and specific heat capacity to use to find the heat involved when I place a hot ionic solid into water? Do I use the mass of the solid or the water?
  
• What is the difference between ground state electron configurations and otherwise?
  
• Explain the hybridization of #"AgC"_2"H"#?
  
• Another Thermo Question?
  
• How would I determine all the possible term symbols for an #s^1p^2# electron configuration (such as first-excited-state boron)?
  
• What is the bond order of any molecule containing equal numbers of bonding and antibonding electrons?
  
• Explain how real machines can never recover the full amount of energy they were supplied with?.
  
• Why does atomic radii decrease going from the bottom left to the upper right of the periodic table?
  
• What is the standard cell potential for the reaction of silver cation with aluminum metal?
  
• Use the Debye-Huckel equation to evaluate #gamma_(pm)# for a #"0.0200 mol/kg"# #"HCl"# solution, with methanol as the solvent, at #25^@ "C"# and #"1 atm"#?
  
• Why is it not advisable to wear contact lenses in lab?
  
• What is gram atom? 5 g atoms of Nitrogen, how much it would be? Thank you.
  
• How would a graph of pressure versus volume appear for a given quantity of gas?
  
• According to MO theory, what does the overlap of two s atomic orbitals produce?
  
• Are there any circumstances under which an accurate measurement may not be precise?
  
• Explain how Henry's law works?
  
• What is the molality for an aqueous solution whose freezing point dropped by #15^@ "C"# due to addition of #"CaCl"_2(s)#? #K_f = 1.86^@ "C/m"# for water.
  
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