Answers created by Professor Sam

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• If the #"pH"# of an aqueous solution of ammonium chloride is #4.60#, what is the #K_h# value of #"NH"_4^(+)#?
  
• What is the derivative of #f(x)=cos^2x-cosx^2dx#?
  
• Are atoms with an atomic number over 83 stable or unstable?
  
• Question #ff1a2
  
• What is the net ionic equation for the reaction #Na^+(aq) + C_2H_3O_2^-(aq) + H^+ (aq) + Cl^- (aq) -> Na^+(aq) + Cl^- (aq) + HC_2H_3O_2(aq)#?
  
• How do you solve #8w + 42= - 2( w - 1)#?
  
• How do you solve #3x-10x+5=0#?
  
• How do you solve #2y = 4 – 6x # and #3y + 9x = 6#?
  
• How do you solve #x^2 = x + 2 #?
  
• Question #79b65
  
• What are produced when a base is dissolved in water?
  
• Given that #DeltaG# for the reaction #4NH_(g) + 5O_2(g) -> 4NO(g) + 6H_2O(g)# is -957.9 kJ, what is #DeltaG)f# of #H_2O#?
  
• What is the molar entropy of a system with 150000 microstates at a certain temperature?
  
• Question #57ac0
  
• Question #55520
  
• Are chemical equation balancer on internet true?
  
• What is the term for the lumps that form when an acid is added to milk?
  
• Question #eafbb
  
• Question #0837e
  
• How do you balance and translate this reaction: #Ca(OH)_2(aq) + H_2SO_4(aq) -> H_2O(l) + CaSO_4(s)#?
  
• Question #8f7c2
  
• Suppose a balloon containing 1.30 L of air at 24.7°C is placed into a beaker.containing liquid nitrogen at -78.5°C. What will the volume of the sample of air become (at constant pressure)?
  
• Is walking a verb or a gerund in the sentence: "We will be walking a mile during recess today."?
  
• Question #f8a59
  
• Question #444c2
  
• What is the #DeltaH_f^@# of liquid water ? Show calculation with bond energies
  
• Question #2f974
  
• Question #206cb
  
• Question #d9f07
  
• How many alpha particles are emitted in the series of radioactive decay events from a U-238 nucleus to a Pb-206 nucleus?
  
• Question #67a25
  
• If 0.40 mol of a gas in a 3.7 L container is held at a pressure of 175 kPa, what is the temperature of the gas?
  
• Question #08525
  
• Question #a721d
  
• Question #fd7ab
  
• Question #03712
  
• A 60 g piece of metal at an initial temperature of 92°C is transferred into 70 g of water initially at 24.5°C. The final temperature of the water and the metal is 40°C. How do you determine the specific heat of the metal?
  
• Question #be5e0
  
• What is a distributive numeral adjective?
  
• What is the formula for the compound dinitrogen pentoxide?
  
• How do you get ethanoic acid from ethyne gas?
  
• How would you balance this equation: #?Pb(NO_3)_2 → ?Pb + ?NO_2 + ?O_2#?
  
• Question #95a18
  
• What is #K_a# of #"ZnCl"_2# ?
  
• Question #d327a
  
• Are electrons, protons, or neutrons the smallest particles? If not what are?
  
• Why is #ZnCl_2# is an acid though it does not have a #H^+# or a #OH^-#?
  
• For the reaction: #N_2(g) + 2O_2(s) rightleftharpoons 2NO_2(g)#, #K_c# - #8.3x10^-10# at 25 °C. What is the concentration of #N_2# gas at equilibrium when the concentration of #NO_2# is five times the concentration of #O_2# gas?
  
• If a sample of N gas was put into a flexible container at an pressure of 25.5kPa, temperature of 35.9 C and a volume of 500. mL, what would the final temperature of the gas be if the pressure was changed to .625 atm and the volume was change to 625mL?
  
• Question #c11d7
  
• Question #c6feb
  
• Question #65f39
  
• Question #e0d9c
  
• Question #22344
  
• How do you find the molar mass of sulfur hexafluoride?
  
• Which of these is NOT true?
  
• Question #1699a
  
• How would you order the following elements with respect to electron affinity: #Cl^-, Ar, K^+, Ti, Ti^(+2)#?
  
• When a proton is released, one element changes into another. What is this process called?
  
• Question #37f75
  
• What is the pH of a mixture that contains 0.60 M # HCl# and 0.30 M #HNO_2#?
  
• How do you solve #-\frac { 2} { 3} z = - 6#?
  
• How can you find heat of formation of water?
  
• How do you evaluate #2\cdot ( - 2) + ( ( - 1) ^ { 2} - 3) ^ { 3}#?
  
• Question #42e00
  
• What mass of #Mg(OH)_2# is produced when 100 mL of 0.42 M #Mg(NO_3)_2# is added to excess #NaOH# solution?
  
• Which nuclide will decay by positron and what isotope will be the left over? Both answers must be correct. (Numbers represent the mass number): 32S, 32P; 26P, 26S; 14O, 14N; 14N, 14O
  
• How do you determine alpha decay?
  
• The #K_sp# of #Al(OH)_3# is #2*10^-32#. At what pH will a 0.9 M #Al^(3+)# solution begin to show precipitation of #Al(OH)_3#?
  
• When silver nitrate solution is added in solution containing nitrate, chloride and iodide ion, which salt will be precipitated first?
  
• Barium sulfate, #BaSO_4#, is so insoluble that it can be swallowed without significant danger, even though #Ba_2^+# is toxic. At 25 °C, 1.00 L of water dissolves only 0.00245 g of #BaSO_4#. How do you calculate Ksp for #BaSO_4#?
  
• A sample of gas has a volume of 240. L at 4.00 atm of pressure and a temperature of 1091K. What is the volume at STP?
  
• If the pressure of 50.0 mL of oxygen gas at 100°C increases from 735 mm Hg to 925 mm Hg, what is the final volume? Assume the temperature remains constant.
  
• Chlorine reacts with water according to the equation: #Cl_2 + H_2O -> HCIO + H^+ + Cl^-#. Given this, how do you write an equation to show how iodine reacts with water?
  
• A solution is prepared by dissolving 40.0 g of sucrose, in 250 g of water at 25°C. What is the vapor pressure of the solution if the vapor pressure of water at 25°C is 23.76 mm Hg?
  
• Living matter has a carbon-14 activity of about 16 counts/min per gram of carbon. What is the age of an artifact for of which the carbon-14 activity is 8 counts/min per gram carbon?
  
• How do you solve #6/5=2/(5n)#?
  
• How do you solve #3 / |2x-1| >=4 #?
  
• Hydrofluoric acid, HF(aq), cannot be stored in glass bottles because compounds called silicates in the glass are attacked by the HF(aq). Sodium silicate (Na2SiO3), for example, reacts as follows: Na2SiO3(s)+8HF(aq)→H2SiF6(aq)+2NaF(aq)+3H2O(l)?
  
• The #Ka# of phosphoric acid, #H_3PO_4#, is #7.6 x 10^-3# at 25#"^o#C. For the reaction #H_3PO_4(aq) -> H_2PO_4(aq) + H^+(aq)# #DeltaH# = 14.2 kJ/mol. What is the Ka of #H_3PO_4# at 60#"^o#C?
  
• A physicist must make sure that the temperature of a metal at 0 deg C gets no colder than -80 deg C. The physicist changes the metal's temperature at a steady rate of -4 deg C per hour. For how long can the physicist change the temperature?
  
• Question #fdcdd
  
• A quantity of a gas at a temperature of #223# #K# has a volume of #100.0# #dm^3# To what temperature must the gas be raised, while the pressure is kept constant, to give a volume of #185# #dm^3#?
  
• Glucose + 2X -enzymes-> 2 Pyruvic acid + 4ATP. What substances is indicated by "X" in this equation?
  
• What is the pressure of a sample of #CH_4# gas (6.022 g) in a 30.0 L vessel at 402 K?
  
• What is the vapor pressure of water at 105°C?
  
• If I had #N# fermions, how could I determine the number of ways I can place these into #g# distinguishable containers? For example, how could I determine how many ways I could place #54# electrons into #54# #p# orbitals?
  
• How many moles of #FeO# are produced if 8 moles of #SO_2# are produced in #2CuFeS_2 + 5O_2 -> 2Cu + 2FeO + 4SO_2#?
  
• A balloon has a volume of 2.9 L at 320 Kelvin. If the temperature is raised to 343 Kelvin, what will its volume be?
  
• Which missing item would complete this alpha decay reaction?
  
• How do you solve #5x^2-10x=7x^2+17# using any method?
  
• Iron oxide reacts with aluminum to give aluminum oxide and iron. What kind of chemical reaction is this?
  
• Question #c4606
  
• Why is it necessary to maintain a constant temperature in an experiment to measure an equilibrium constant?
  
• How many grams are there in #1.5 x 10^25# molecules of #CO_2#?
  
• Who is Avogadro and what is a mole?
  
• How many grams are there in 5.0 moles of #H_2O#?