First Year Chem Help

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Questions with answers except I don't know how to work them out.

For the equilibrium CO (g) + H2O (g) <---> CO2(g) +H2(g), Kc at 700K is 5.1. If m mol of all 4 species are mixed in a vessel of fixed volume at 700K nd the system is allowed to equilibrate, which of the following is true for which [CO]/[CO2] equals?

Answer: 0.44

A 1.00L aqueous solution contains 0.0550 moles of acetic acid (CH3COOH) and 0.0350 moles of sodium acetate (CH3COONa). What is the pH of the oslution when 0.0050 moles of HCI are added without change in volume?

(pKb(Ch3COO-)=9,3)

Answer: 4.4

X-rays of wavelength 1.54A are relfected from planes that are 2.33A apart in an aluminium crystal. At what angle of theta is the reflection located. You may assume that the reflection is a first order reflection ie. n=1

Answer: 19.3degrees

Solid CaF2 is added to an aqueous solution that contains fluoride ion At equilibriu some CaF2 remains undissolved and the equilibrium fluoride ion concentration is 0.020M. What is the calcium ion concentration? (Ksp (CaF2)= 4.0 x 10^-11)

Answer: 1.0 x 10^-7 M