Physical Chemistry Answers

how much 10% solution is needed to make 500ml of 2% solution

A sample of lake water at 25C is analyzed and the following parameters are found for it: total alkalinity 6.2 10 4M phenolphthalein alkalinity 1.0 10 5 M pH 7.6 hardness 30.0 mg L1 [Mg2] 1.0 10 4M Extract all possible single ion concentrations that you can by combining one or more of these data. Also determine whether or not the water is at equilibrium with respect to the carbonate– bicarbonate system and whether or not it is saturated with calcium carbonate.

For the decomposition of nitrosyl bromide at 10 °C
2 NOBr(g) 2 NO(g) + Br2(g)
the average rate of disappearance of NOBr over the time period from t = 0 s to t = 14.1 s is found to be 3.51×10-3 M/s.

What is the average rate of appearance of Br2 over the same time period?

a) Sketch the temperature-composition ("T-x") phase diagram for acetone ((CH3)2CO) and chloroform (CHCl3) mixtures based on the following data:
- Boiling point of pure acetone: 56.2 oC
- Boiling point of pure chloroform: 61.2 oC
- Boiling point of the acetone-chloroform azeotrope: 64.7 oC
- Composition of the azeotrope (by weight): 21% acetone, 79% chloroform
- Atomic weights (in g/mol): H: 1.01, C: 12.01, O: 16.00, Cl: 35.45
Hint: First calculate the acetone mole fraction that corresponds to 21% acetone by weight.
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b) On your sketch of the phase diagram, explain how you would determine the composition of the vapor phase and the liquid phase for a system at 61.2 oC having an overall acetone mole fraction of z = 0.80

A sealed container was filled with 0.300 mol H2(g), 0.400 mol I2(g), and 0.200 mol HI(g) at 870 K and total pressure 1.00 bar. Calculate the amounts of the components in the mixture at equilibrium given that K = 870 for the reaction H2(g) + I2(g) equilibrium reaction arrow 2 HI(g).

The equilibrium constant for the reaction :
H₂(g)+S(s)⇔H₂S(g) is 20.0 at 925K and 10.25 at 1000K, respectively.
To calculate the standard enthalpy of reaction.

The following reaction was studied in a closed vessel 2N2O5(g) ↔ 4 NO2 (g) + O2 (g) It was found that the concentration of NO2 increased by 2 X 10-2 mol/L in five seconds. Calculate (i) Rate of reaction (ii) the rate of change of concentration of N2O5

50 ml of a 0.1m koh solution is added to 25ml of 0.2m hcl. the volume of the resulting solution was made upto 500 ml. now 0.745 gram of solid kcl is added to solution . what is the concentration of cl- in the final solution . what volume of 0.1 m agno3 would be requried for complete precipitaion of cl - ions as silver chloride

1. Add 0.05moll-mgcl 2 solution.Can precipitation occur when ammonia water is mixed in equal volume? to 0.1mol · L-

Under what conditions the Maxwell Boltzmann statictics, Bose einstein statictics and Fermi diers statistics become identical