Questions asked by Reena D.

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• How many grams of CO2 would be needed to have the same number of moles of CO2 as there are in 52.2 grams of H2O?
  
• How many grams of titanium could be obtained from a 27.00 mole sample of Ti6Al4V?
  
• If 0.250 g of a gas sample represents 1.05x10–2 mol, what is the molar mass of the gas?
  
• When #0.121" moles of HCl"# reacts with #0.399" moles of NH"_3#, how much #"NH"_3# is consumed?
  
• A 0.281 g piece of solid magnesium reacts with gaseous oxygen from the atmosphere to form solid magnesium oxide. In the laboratory a student weighs the mass of the magnesium oxide collected from this reaction as 0.254g. What is the percent yield of this?
  
• When 0.121 moles of HCl reacts with 0.399 moles of NH3, how much NH3 is consumed?
  
• Driving 1000 miles a month is not unusual for a short-distance commuter. If your vehicle gets 19.70 mpg, you would use approximately 50.76 gallons of gasoline every month. If gasoline is approximated as C8H18 (density = 0.703 g/mL)...?
  
• How do I write the overall ionic equation for 2H3PO4(aq)+3Ba(OH)2=6H2O(l)+Ba3(PO4)2(s)?
  
• A mouthwash, which comes in a concentrated syrup, contains red dye 40. The red dye 40 syrup is diluted by a factor of 2 three times. If the red dye 40 concentration is #6.60xx10^-3" M"# in the original syrup, what is its concentration in dilution 3?
  
• Many homeowners treat their lawns with CaCO3(s) to reduce the acidity of the soil. Write a net ionic equation for the reaction of CaCO3(s) with a strong acid?
  
• How many milliliters of a 0.160 M potassium chloride solution should be added to 49.0 mL of a 0.270 M lead(II) nitrate solution to precipitate all of the lead(II) ion?
  
• Calculate the heat capacity of a calorimeter if the combustion of 5.000 g of benzoic acid led to a temperature increase of 20.00 °C. The heat of combustion of benzoic acid is -26.38 kJ/g. ?
  
• The standard enthalpies of formation, ΔH∘fΔHf∘, for C2H2(g), O2(g), CO(g), H2O(g), and CO2(g) are given in the table. Use this information to calculate the overall heat of the reaction that converts 1 mole of C2H2(g) and a stoichiometric amount of O2(g).?
  
• A balloon is partly inflated with 5.15 liters of helium at sea level where the atmospheric pressure is 992 mbar. The balloon ascends to an altitude of 3.00 x 103 meters, where the pressure is 857 mbar.?
  
• Buoyancy for the Goodyear blimp Spirit of Innovation comes from 203,000 ft3 of helium. Calculate the mass of this much helium at 22.00 °C and 0.987 atm pressure.?
  
• The density of a test gas is to be determined experimentally at 302.2 K using an apparatus constructed of a 4.350 L glass bulb volume that is attached to a vacuum pump. The mass of the evacuated bulb is 21.072 g.?
  
• At 20.0°C, the vapor pressure of ethanol is 45.0 torr, and the vapor pressure of methanol is 92.0 torr. What is the vapor pressure at 20.0°C of a solution prepared by mixing 31.0 g methanol and 59.0 g ethanol?
  
• The vapor pressure of pure cyclohexane (C6H12) and pure toluene (C7H8) at 20°C are 66.9 and 21.1 torr, respectively. The total pressure above a mixture of these two liquids is 50.0 torr. Calculate the mole fraction of cyclohexane in the liquid mixture?
  
• Calculate the molar mass of the artificial sweetener?
  
• An ideal solution is formed from mixing six grams of the nonvolatile solute urea, CH4N2O, with 32 grams of methanol, CH3OH. The vapor pressure of pure methanol at 20 degrees celsius is 89 mmHg...?
  
• The rubbing alcohol used to clean test tubes is 70% isopropanol, C3H8O, by volume. 100 mL of solution contains 54.95 g of isopropanol and 29.95 g of water. The vapor pressure of water is 20 degrees celsius is .0230 atm and the vapor pressure...?
  
• Until roughly 1970, tritium (3H), a radioactive isotope of hydrogen, was a component of fluorescent watch dials and hands. For 3H, t1/2 = 12.3 yr. Assume you have such a watch. If a minimum of 14.0% of the original tritium is needed to read the dial in?
  
• The rate constant for the reaction: NO2(g)+O2(g)---->NO3(g)+O2(g) was determined over a range of 40.0 K, with the following results. Determine the activation energy for the reaction (kJ/mol) and calculate the rate constant of the reaction at 300K?
  
• According to solubility rules, most F- containing compounds are insoluble but most Cl-, Br-, and I- containing compounds are soluble. Briefly explain this observation?
  
• A particular drain cleaner contains #"NaOH"#. What is the value of #["OH"^(-)]# in a solution produced when #"15.0 g"# of #"NaOH"# dissolves in enough water to make #"375 mL"# of solution?
  
• What is the pH of a solution that has a [OH–] of 3.07×10-3 M ?
  
• Seawater has a pH of 8.100. What is the concentration of OH–?
  
• Calculate the pKa of hypochlorous acid. The pH of a 0.015 M solution of hypochlorous acid has a pH of 4.64 ?
  
• What is the pH of a solution made by dissolving 5.36 grams of calcium fluoride in enough water to make 430 mL of solution? The Ka for HF is 6.8x10–4.
  
• Complete the chemical reaction that occurs when dimethylamine (CH3)2NH reacts with water?
  
• The venom of biting ants contains formic acid, #"HCOOH"#. What is the #"pH"# of a #"0.0700-M"# solution of formic acid?
  
• Nicotine is responsible for the addictive properties of tobacco. Assume Kb1 = 1.0×10-6 and Kb2 = 1.3×10-11 . Determine the pH of a 1.15×10-3 M solution of nicotine.?
  
• What is the pH of a 0.325 M solution of H2SO4? Ka2 = 1.20×10–2?
  
• What is the concentration of ammonia if 15.34 mL of 1.14 M HCl is needed to titrate a 10.00 mL sample of the cleaner?