Sunday
May 26, 2013

Posts by harry


Total # Posts: 197

chemistry
enthalpy change^H is +23kJ mol-1 of phosphine (PH3) for the reaction 2P(s)red+3H2(g)---->2PH3(g) a) Calc. entropy change for this reaction. Explain how this information allows you to determine the spontaneity or non-spontaneity of this reaction at any temp (S for PH3 is 210...

chemistry
a gas sample heated in a cylinder uses 650kJ of heat. a piston that compresses this gas does 800kJ of work. What is the change in internal energy, ^E of the gas during this process?

chemistry
list the following substances in order of increasing molar entropy at 25'c. H2O(l), H2O(g), H2O(s), C(s), Ar (g) Explain your reasoning

chemistry
the standard free energies of formation of SO2(g) and SO3(g) are -300.4 and -370.4kJ mol-1 respectively. Calculate the value of the equilibrium constant at 25'C for the reaction 2SO2(g)+O2(g)==>2SO3(g)

writing
I need help to write a summery for the open univercity please write for me one Thanks

science
Which is the higher density of polyethylene, linear or branched? Select the choice with the best accompanying explanation

science
A pressure vessel contains a large volume of CO2 gas at 10 atm pressure. A membrane composed of a poly(ether ketone) polymer with thickness 100 microns and net effective area of 100 cm2 covers a small perforated port in the container. The solubility of CO2 at 10 atm is 6.97 x ...

science
What is the degree of polymerization, n, of polypropylene with a molecular weight of 600,000 g/mole?

science
Calculate the surface energy of the (100) surface of niobium. The enthalpy of atomization of niobium is 745 kJ/mole. Express your answer in units of J/cm2.

science
What is the pH of 50 mL of a 0.2M glycolic acid aqueous solution after adding 5 mL of 0.25 M KOH? The pKa of glycolic acis is 3.83 at 25 .

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