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For a hydrogen atom, calculate the energy of a photon in the Balmer series that results from the transition n = 3 to n = 2. The Rydberg constant is 1.0974 × 107 m-1. (h = 6.6262 × 10-34
A 5.96-g sample of homogentisic acid, a weak organic acid having Ka=4.0 x 10^-5, is dissolved in 35.0 mL of water and its pH is measured to be 2.20. What is the molar mass of homogentisic acid?
500 mL of a gas is collected under the following conditions, Pressure = 750 torr and temperture = 24 degree celsius. What will the new volume be when the temperature is 341 K and the pressure is 4.
Two samples of calcium flouride are decomposed into their constituent elements. The first sample produced 1.64 g of calcium and 1.56 g of flourine. If the second sample produced 294 mg of fluorine,
Find the number of moles of water that has been lost from MgSO4.7H2O, when you heat 2.9560 g of this hydrate to give the anhydrous MgSO4. Molar mass of MgSO4.7H2O = 246.5 g/mol and molar mass of H2O
Calculate the density of a volatile liquid in its gaseous state at pressure = 752.0 mm Hg, and temperature = 99.5 0C , if its molar mass is 84.0g/mol; R = 0.0821 atm.l / mol.K.
When a non-volatile solute dissolved in water the freezing point of the solution is lowered while its boiling point is increased. Give a practical example from our life on both cases.
Would you xpect the α-protons of a thioester to have a lower or higher pKa than an ester? Why? Remember the pKa values for the α-protons of several FG's: aldehyde(17), ketone(21), ester(
Calculate the percent of radioactive parent atoms remaining 2 hours after medicine is administered. The percent is the fraction x 100%.
A one mole sample of an ideal gas with a Cv=1.5R, initially at 320K and 1 atm pressure is allowed to undergo an reversible is othermal expansion against a constant external pressure of 0.5atm.
Calculate the equilibrium constant for the reaction at that temperature of at equilibrium the partial pressures are PSO2 = PNO2 = 0.50 atm, and PNO = PSO3 = 2.0 atm.
How will the fist mL of distillate from the simple distillation differ from the first mL distillate of the factional distillation? If the thermometer bulb is placed too high how will this affect you
Calculate the osmotic pressure of a magnesium citrate laxative solution containing 30.0 g of magnesium citrate in 251 mL of solution at 37 degrees C.
Calculate the osmotic pressure of a magnesium citrate laxative solution containing 26.5 of magnesium citrate in 220 of solution at 37 (approximate body temperature). Assume complete dissociation of
In what direction will a net change occur if one brings together 0.0500 mol CO2,0.0700 mol H2 , 0.0400 mol CO, and 0.0850 mol H2O?
Consider the series of acids HOCl, HOClO, HOClO2, and HOClO3. What is the oxidation state of the chlorine in each of these molecules?
Assuming the volumes of all gases in the reaction are measured at the same temperature and pressure, calculate the volume of water vapor obtainable by the explosive reaction of a mixture of 725 mL o
At 85 C the vaper pressure of A is 566 torr and that B is 250. Caculate the composition of a mixture of A and B that boils at 85 C when the presure is 0.60atm. Also Caculate the composition of the
A food chemist combusts 56g of a chocolate bar in a calorimeter containing 1.5 L of water (density Water = 1g/1ml). The initial temperature was 19 degrees Celsius and the final temperature was 73 d
Find the empirical formula for the ion MnxO-y using this experimental info: The reaction below takes place in a 608 mL volume of solution. A 0.228 M solution of MnxO-y reacts with excess Br- and H+
What is the minimum frequency of light necessary to emit electrons from sodium via the photoelectric effect?
The student precipitated the Ca+2 ion as CaC2O4 from 75.0 mL of the water sample and removed the precipitate by filtration. The student then adjusted the water sample volume to 100.0 mL.
How many people can Tanzania currently feed? Hint: Start by finding the total energy that Tanzania produces from food in one year's time. Then use that number and the number of kcals that one person
You are titrating 15.0 mL of an aqueous acetic acid with standard 0.300 Molarity NaOH. The equivalence point is reached at 9.00 pH, after 30,0 mL of the standard base had been added. Calculate Ka f
A solution contains 4.08 g of chloroform (CHCl3) and 9.29g of acetone (CH3COCH3) . The vapor pressures at 35 degrees C of pure chloroform and pure acetone are 295 torr and 332 torr, respectively.