Chemistry MOCK FINAL exam, chemistry homework help

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Please hand-write your results to show the correct procedure .Results without showing the procedure will not be considered in any case. (Always use correct significant figures)

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CHEM-112-01 General Chemistry II lecture , MOCK FINAL EXAM_1_ is for you to practice at home before FINAL , (11 +13 +14+15+16+17+19+ 20) Please hand-write your results to show the correct procedure .Results without showing the procedure will not be considered in any case. (Always use correct significant figures) 1. Which member of each of the following pairs of substances would you expect to have a higher boiling point? SO2 and CO2, EXPLAIN your ANSWER 2. List the types of intermolecular forces that exist between molecules (or basic units) in each of the following species: benzene (C6H6) EXPLAIN your ANSWER. 3. A solution is prepared by condensing 4.00 L of a gas, measured at 27°C and 750. mmHg pressure, into 59.0 g of benzene. Calculate the freezing point of this solution. 4. The half-life of a first-order reaction is 13.2 min. If the initial concentration of reactant is 0.080 M, how many minutes it takes for it to decrease to 0.055 M. 5. Consider the reaction Suppose that at a particular moment during the reaction nitric oxide (NO) is reacting at the rate of 0.0701 M/s. • At what rate is NO2 being formed? • At what rate is molecular oxygen reacting? 6. How many grams of sulfur (S8) must be dissolved in 110. g of naphthalene (C10H8) to make a 0.12 m solution? 7. [ EXPLAIN your ANSWER FOR CASE A) B) C) D) E) ( NO EXPLANATION OR WRONG EXPLANATION OR PARTIAL EXPLANATION = 0 pts) ] For the endothermic reaction CaCO3 (s) CaO (s) + CO2 (g) Le Châtelier's principle predicts that ________ will result in an increase in the number of moles of CO2. A) increasing the temperature B) decreasing the temperature C) increasing the pressure D) removing some of the CaCO3(s) E) none of the above 8. The equilibrium constant Kc for the decomposition of phosgene, COCl2, is 4.63 × 10 −3 at 527°C: Calculate the equilibrium partial pressure of all the components, starting with pure phosgene at 0.75 atm. 9. Determine the pH of a 0.50 M aqueous solution of CH3NH2 (methylamine). The Kb of methylamine is 4.4 × 10-4. 10. An aqueous solution contains 0.0055 M of methylamine. Kb for methylamine is 4.0 × 10-4. The concentration of hydroxide ion in this solution is ...? 11. Ka for HCN is 4.9 × 10-10. What is the pH of a 0.000060 M aqueous solution of sodium cyanide? 12. Determine the pH of a solution that is 0.025 M in NH3 and 0.020 M NH4Cl. 13. In a titration experiment, 20.0 mL of 0.800 M HCOOH neutralize 10.0 mL of Ba(OH)2. What is the concentration of the Ba(OH)2 solution? 14. Calculate whether or not a precipitate will form if 2.00 mL of 0.30 M NH3 are added to 3.0 L of 1.0 × −3 10 M FeSO4. 15. The Kb for methylamine (CH3NH2) at 25 °C is given in Appendix D. A)_ Write the chemical equation for the equilibrium that corresponds to Kb. B)_ By using the value of Kb, calculate ∆G° for the equilibrium in part (a). + -9 C)_ What is the value of ∆G at equilibrium? D)_ Whatisthevalueof∆Gwhen[H ]=7.0x10 + -3 M,[CH3NH3 ]=2.0x10 M,and [CH3NH2] = 0.099 M? 16. Using tabulated S° values from Appendix C consider the following reaction: CaCO3(s, calcite) + 2HCl(g) CaCl2(s) + CO2(g) + H2O(l) A)_(5pts)_Calculate ∆S° values for the following reaction by using tabulated S° values from Appendix C B)_(6pts)_ Explain the sign of ∆S°: why is it positive OR why is it negative ? 17. The element gallium (Ga) freezes at 29.8 °C, and its molar enthalpy of fusion is ∆Hfus = 5.59 kJ/mol. Calculate the value of ∆S when 62.0 g of Ga(l) solidifies at 29.8 °C. 2+ 18. Consider the following redox reaction in basic conditions: Ba (aq) + 2OH (aq) + H2O2(aq) + 2ClO2(aq) Ba(ClO2)2(s) + 2H2O(l) + O2(g) A)_ Write the oxidation number of every elements inside this equation. B)_ Which compound is the reducing agent? C)_ Which compound is the oxidizing agent? 2+ 19. A voltaic cell is constructed that is based on the following reaction: Sn (aq) + Pb(s) Sn(s) + 2+ 2+ Pb (aq) A)_(6pts)_If the concentration of Sn in the cathode half-cell is 2.50 M and the cell 2+ generates an emf of +0.39 V, what is the concentration of Pb in the anode half-cell? 2B)_(5pts)_If the anode half-cell contains [SO4 ] = 2.50 M in equilibrium with PbSO4(s), what is the Ksp of PbSO4? 20. Consider the following half-reactions: N2(g) NH3 (g) (basic solution) A)_ Balance the following half-reaction. B)_ Is the half-reaction an oxidation or a reduction?
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Most of the solutions are typed and included in the word document. 4 of the problems are handwritten and attached individually. Please note that a few of the problems asked you to look up values in your text. I found those values online. They should not differ too greatly from what is in your text, but you may want to double check them. The values will not change the process, but would change the calculations just slightly.Please let me know if you have any questions about these problems.

CHEM-112-01 General Chemistry II lecture , MOCK FINAL
EXAM_1_ is for you to practice at home before FINAL , (11 +13
+14+15+16+17+19+ 20) Please hand-write your results to show
the correct procedure .Results without showing the procedure will
not be considered in any case. (Always use correct significant
figures)
1.
Which member of each of the following pairs of substances would you expect to
have a higher boiling point? SO2 and CO2, EXPLAIN your ANSWER
The boiling point of a compound will increase as the strength of the intermolecular forces
increases. SO2 is a polar molecule due to the 2 sets of unpaired electrons. That means
the forces will include dipole-dipole forces. CO2 is a non-polar molecule due to the
linear shape. A non polar molecule like CO2 has only London dispersion forces as
intermolecular forces. SO2 has the stronger intermolecular forces, so it will also have the
higher boiling point.

2.
List the types of intermolecular forces that exist between molecules (or basic
units) in each of the following species: benzene (C6H6) EXPLAIN your ANSWER.
There are 3 possible intermolecular forces: dipole-dipole forces between polar molecules,
London dispersion forces between all molecules and hydrogen bonding between polar
molecules where H is bonded to N, O or F.
Benzene is a non-polar molecule. There is not N, O or F to bond to the H in the benzene.
This means that the only intermolecular forces in benzene are London dispersion forces.

3.
A solution is prepared by condensing 4.00 L of a gas, measured at 27°C and 750.
mmHg pressure, into 59.0 g of benzene. Calculate the freezing point of this solution.
To calculate freezing point depression, you need to know the molality of the solution
(in moles of solute / kg solvent) and the depression constant for the solvent.
In this case the solvent is benzene which has kf value of 5.12 degC / m.

Since benzene is the solvent, its mass should be in kg instead of g.
59.0 g benzene = 0.059 kg benzene
Then we need to figure out the number of moles of the gas that is condensed into the
benzene. For this you can use the ideal gas law.
V = 4.00 L, P = 750 mmHg and T = 27 deg C + 273.15 = 300.15 K
I looked up the value of R with the correct units. If you only have one value of R
available you would need to convert the pressure and temperature units to the
appropriate one.
R = 62.36367 L mmHg / K mol
PV = nRT
PV
n=
RT
4.00 L∗ 750 mmHg
n=
L mmHg
62.36367
∗ 300.15 K
mol K
n= 0.1602696 mol gas

Now that the number of moles of gas has been determined you can find the molality
of the solution.
0.1602969 mol
0.059 kg
m= 2.71643445635 m
m=

Finally you can calculate the freezing point depress...


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