Homework Help for Chemistry (page 9842)
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a) In any spontaneous process, the entropy of the system alwaysincreases.
b) All spontaneous processes are exothermic.
c) Any spontaneous process is accompanied by a positive free energychange.
d) In order for a process to be spontaneous, the process must beexothermic and the entropy of the system must increase.
e) None of the statements above are true.
I know the answer is e, but I don't know why the other answers werefalse and was hoping that someone could shine some light as to whya-d are false. Thanks!
7. The Ksp of Bi2S3 is 1.6 x 10^-72. What is the molar solubilityof this compound in aqueous solution?
a. 1.6 x 10^-72 M
b. 4.4 x 10^-15 M
c. 1.7 x 10^-15 M
d. 1.2 x 10^-24 M
8. The pH of a 0.25 M weak monoprotic acid (HA) solution is 3.50.What is the Ka value for this acid?
a. 7.1 x 10^-4
b. 1.0 x 10^-7
c. 1.3 x 10^-3
d. 4.0 x 10^-7
e. 1.0 x 10^7
10. Calculate the pH of a buffer solution which contains 0.25 Mbenzoic acid (C6H5CO2H) and 0.15 M sodium benzoate (NaC6H5CO2).Given Ka = 6.5 x 10-5.
12. The molar solubility of MgCO3 is 1.8 x 10^-4 mol/L. What is Kspfor this compound?
a. 1.8 x 10^-4
b. 3.6 x 10^-4
c. 1.3 x 10^-7
d. 3.2 x 10^-8
e. 2.8 x 10^-14
1.8 x 10-5 = x2 / (0.10 - x) = ca. x2 / 0.10
Which of the statements below can be cited as proof that theassumption is reasonable?
simplifications can be made when [HA]initial is exactly equal to100Ka
the assumption works if x is within 5% of [HA]initial
for the assumption to be used, the pH of the solution cannot beless than 5.0
x is small so [HA]equilibrium<< [HA]initial
I know the answer to the first part that if the % recovery will bereduced if more than the minimum amount of solvent is used todissolve the solid but I cannot find the reason for this. cananyone explain?
1.) I need to make a 100mL phosphate buffer solution with a pHof 7.5. I have 100 mL of a 0.1M Na2HPO4 solution and 100 mL of a0.1M NaH2PO4 solution. How much of each should I use and what willbe the concentration of the buffer? pKa=7.2. Please showcalculations.
I am doing a lab on enzyme assay optimization and need to test ALPwith
various different reagents using a spectrophotometer. I am prettyconfused
about how to go about this so anyone that has any helpfulsuggestions would be
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