I have a sample Final exam that has 24 questions with answers. I need the steps that lead to the answers for all the questions please. The attached file is the exam.
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CHEM 110B Sample Final Exam
1. Complete and balance:
? ____ 255
101?? ______ + 2 0?
3Cl- + 2CrO4-2 + 13 H+ ? 3 HClO + 2 Cr+3 + 5 H2O
3. Complete and balance in acidic solution:
8H+ + 3ZnS
+ 2NO3- ? Zn+2 + 3 S
+ 2 NO + 4 H2O
4. Complete and balance in basic solution:
2OH- + 1 BrO3- + 1 F2 ? 1 BrO4- + _2 F- + H2O
5. Give the bar (Lewis) structure for ClO2-. The skeleton structure is ( I WILL DISCUSS IN CLASS)
6. Is the molecular shape of the AsCl3 molecule straight line (linear), pyramidal, bent, trigonal planar or
tetrahedral? The skeleton structure is: ( NOT THERE FOR FINALS)
7. An unknown gas has a density of 0.154 g/L at -12.0 ?C and 0.125 atm. What is the molecular mass of
this unknown gas? Answer: 26.4g/mol
8. What is the empirical formula of a compound if a 2.014 g sample contains 1.457 g Fe and 0.557 g O?
9. What products (if any) will precipitate if solutions of K2CO3, Al2(SO4)3 and Pb(NO3)2 are mixed?
Al2CO3(S) PbCO3(S) and PbSO4 (S)
10. Draw the bar (Lewis) structure and predict the molecular shape of CS3-2 ion. The skeleton structure of
CS3-2 is: ( I WILL DISCUSS IN CLASS)
11. How much of a 9.8 x 10-6 g sample of
Answer: 6.7 X 10-6g
remains after 3155 yr? The half-life of 146? is 5,720 yr.
12. When solutions of aluminum bromide (AlBr3) and sodium sulfide (Na2S) are mixed, aluminum sulfide
(Al2S3) precipitates. Write a balanced net ionic equation for this reaction.
Answer: 2Al3+(aq) + 3S2-(aq) ? Al2S3 (S)
13. The H+ concentration is 0.015 M in a final solution that is made by mixing 25 mL of 0.75 M HClO4 and
75 mL of NaOH with an unknown concentration. What was the NaOH concentration in the unknown
solution? The net ionic equation is given:
H+(aq) + OH-(aq) ? H2O(l)
Answer: 0. 23 M NaOH
14. What is the OH- concentration in a solution made by mixing 65 mL of 0.300 M HCl and 65 mL of 0.375
M NaOH? The net ionic equation is given:
H+(aq) + OH-(aq) ? H2O(l)
Answer: 0. 04 M
3 CO(g) + 7 H2(g) ? C3H8(g) + 3 H2O(g) ,
K = 9.3x 10-2
The concentrations at equilibrium are [C3H8] = 0.154 M, [H2O] = 0.071 M and [CO] = 0.035 M.
Calculate the equilibrium concentration of H2.
Answer: 1.5 M
16. A cube of Cu that is 1.750 cm on each edge is treated with HCl. If 2.57 L of H2 gas is produced at STP,
what mass of Cu remains? (density of Cu = 8.96 g/cm3; 1 mol = 22.4 L) The reaction that occurs is:
Cu + 2 HCl ? CuCl2 + H2
Answer: 48.0 g Cu
17. If 95.10 g AlCl3 are reacted with 59 g of H2SO4, how many grams of Al2(SO4)3 are formed? The
balanced equation is given:
2 AlCl3 + 3 H2SO4 ? Al2(SO4)3 + 6 HCl
Answer: 69 g of Al2(SO4)3
18. How many grams of H2O can be produced by decomposing 16.15 g Fe(OH)3? The balanced equation is
2 Fe(OH)3 ? Fe2O3 + 3 H2O
Answer: 4.085 g H2O
19. What is the volume of HCl gas produced at STP from the reaction of 65 mL of 0.351 M H2SO4 with 17
g of KCl? The balanced equation is given:
2 KCl(s) + H2SO4(aq) ? 2 HCl(g) + K2SO4(aq)
Answer: 1.0 L of HCL
20. To make iced tea, how much ice should be added to 2.72 kg of hot tea at 93 ?C so that the final
temperature is 0 ?C and no ice remains? Assume the heat capacity of tea is the same as water (1.000
cal/g?C) and heat of fusion of water is 79.71 cal/g. Note: For finals any heat problem can be there, so
please practice all practice problems from this chapter.
Answer: 3.2 Kg ice
21. How much energy would be produced by one mole of the elements reacting by the following nuclear
reaction? The molar masses are given below. (The mass-energy conversion is 1 g = 9.0 x 1013 J).
Answer: 1.7 x 1012J
22. Perform the mathematical calculation of measured numbers below and report the answer with the correct
number of significant figures.
(2.35 x 10-8 + 1.225 x 10-7) x (15.59 + 0.41) = ?
Answer: 2.336 X 10-6
23. What is the empirical formula of a compound, a sample of which contains 0.97 g Mg, 0.96 g C and
24. A cylinder with a moveable piston contains 16.81 L of CO2 gas at a temperature of 71 ?C and a pressure
of 1.21 atm. If the temperature decreases to -5 ?C and the pressure remains constant, what volume will
the CO2 gas occupy?
Answer: 13.1 L
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