Equilibrium

Kf=1.38 x 10 -28th power M/s. Kr = 9.3 x 10 10th power M/s. Both constants are at 25 degrees Celsius, how would I find the equilibrium constant at 25 degrees Celsius?

Solving for Ea and A

Data: T1 = 650 T2 = 700 K1 = 0.22 1/m.s K2 = 1.3 1/m.s Ea = R = 8.315 kj/K.mol I am using equation ln k2 - ln k1 = Ln k2/k1 = Ea /R [1/T2 - 1/T1] Since K1 + K2 are in 1/m.s do I have to get the inverse of those figures so that K1 = 4.545 m.s and K2 = .769 m.s? Second, solving for Ea: Ea/8.315 kj/k.mol * [1/700-1/650]= How do I isolate so that I am solving for Ea? How would I solve for A?

Acids/Bases

I need help setting this up to find the pKa so I can determine the strength of the acid. Benzoic acid is an organic acid with a Ka of 6.5x10^-5. It can also be used as a primary standard like KHP. If benzoic acid were used to standardize NaOH, how can I determine if if the equivalence point is acid, basic, or neutral based on the following criteria? pKa < 0 is strong acid 1 10 very weak Also, if more concentrated NaOH is used during standardization could this change any of these results or is the pKa a constant? Thanks for the help!

Colligative Properties

An unknown organic compound is a nonelectrolyte known to be composed of C, N, O, and H. Combustion analysis showed that it contained 67.3% C, 4.62% N, and 6.93% H. A solution made by dissolving 1.20 g of the unknown compound in 25.0 g of benzene had a freezing point of 4.7 degrees Celsius. Determine: a) the empirical formula b) the molar mass c) the molecular formula of the unknown compound

Pressure volume question

I need need help for the following. A flexible gas storage container has a volume of 3.5 x 10^2 L at a temperture of 27 degrees celcius and a pressure of 115 kPa. What is the new volume if the temperture drops to -10 degrees celcius and the pressure drops to 99 kPa?