CHEMISTRY
1074
General Chemistry for
Engineers
Key to the Final Exam, Friday 14 Dec. 2001
Shown is a phase diagram for carbon dioxide. According to this diagram, what phase of carbon dioxide is stable at 4.0 atm and -78 °C?
Solid phase
Shown in the previous question is a phase diagram for carbon dioxide. According to this diagram, which of the following is false?
The triple point for carbon dioxide occurs at T = 31 °C and P = 73 atm.
Which of the following is a polar molecule?
NH3
Which of the following hydroxide ion concentrations represents the most acidic solution in water?
[OH-] = 1.0 x 10-14 M
The heat of combustion of methane is 55.1 kJ/g. What is DH for the combustion reaction of 2.00 moles of methane?
-1770 kJ
Pick the chemical below that in the liquid state possesses dispersion attractive forces and dipole forces.
NF3(l)
Use the solubility product data to decide whether or not a precipitate will form when the following solutions are mixed: 25.0 mL of 5.0 x 10-4 M lead(II) nitrate and 25.0 mL of 2.0 x 10-2 M potassium iodide. Ksp of lead(II) iodide is 8.49 x 10-9.
A precipitate of lead(II) iodide will form.
Which of the following is an addition polymer of CF2=CF2?
Teflon
Pick the state of matter listed below that has the lowest entropy, with molecules located close together and ordered.
Solid phase
A substance that does not dissolve readily in water is described as:
hydrophobic
Which of the following is a weak electrolyte when dissolved in water?
CH3COOH
Polyvinyl chloride has an empirical formula of C2H3Cl. What is the percentage by weight of chlorine in polyvinyl chloride?
56.7 %
Pick the solution below which will be the most basic.
1.0 M NaOH
How many grams of potassium oxide are produced from the combustion of 15.6 g of potassium metal in the presence of excess oxygen gas?
18.8 g of potassium oxide
Select the answer that rounds the following calculation to the correct number of significant figures: 2.573 + 9001 + 2400 + 12500
23900
Which of the following represents the formula for potassium sulfate?
K2SO4
Which of the following is a metal?
Lithium
Pick the number below that has 4 significant figures
47.30
Select the equation below that represents a fission reaction that is correctly balanced:
23592U ® 9038Sr + 14458Ce + 10n + 4 0-1e-
Select the nuclide below that has 18 neutrons and 17 protons.
3517Cl
The table below shows some
bond energy values.
|
Bond Energies (kJ mol-1) |
|
|
|
|
|
C-H |
413 |
|
H-Cl |
431 |
|
C-Cl |
328 |
|
Cl-Cl |
242 |
Using the table above, determine the energy change when one mole of
methane reacts according to the following reaction. CH4 + Cl2 ® CH3Cl +
HCl
104 kJ
is released to the environment.
The element with chemical properties that most resemble element 53 is:
Br
The molar heat capacity of
water is 75.4 J mol-1 K-1. To heat 25,000 g of water from
10.0 °C to 15.0°C requires this many kilocalories.
125
Select the metal compound in which the transition metal atom has the
highest oxidation state.
KMnO4
Under standard conditions the voltage generated by the oxidation of tin
metal to tin(II) ions by iodine solid (which is reduced to iodide ions) is:
+0.67 V
222Rn (half-life = 3.82 days) is the most stable
isotope of the noble gas radon. The presence of this nuclide in homes located
near uranium-bearing minerals is a potential
health hazard and a source of environmental concern. Suppose that a
sample of air is collected from a home, and is monitored for a period of time.
Calculate the percentage of the original 222Rn that remains in the
sample after 10 days.
16.2%
What do you observe when an open container of methanol is exposed to a flame in air?
The methanol burns.
How many moles of carbon monoxide are produced from the incomplete combustion of 2.00 moles of isooctane (C8H18) such that the only carbon containing product is carbon monoxide?
16.00 moles of carbon monoxide
Pick the gas below that would be predicted to diffuse the slowest.
CH3CH2OH(g)
Aluminum can be combined with oxygen gas to produce aluminum oxide, Al2O3. If 0.67 moles of aluminum are reacted with 22.4 L of oxygen gas at 1.00 atm and 100.0° C, which reactant is in excess?
Oxygen gas
How many grams of potassium bromide are produced from the reaction of 15.64 g of potassium metal with 19.00 g of bromine gas?
28.29 g
Sublimation is which of the following?
The conversion between the solid and gas phase
Which of the following is not a chemical or mixture of chemicals?
All of the above are chemicals or combinations of chemicals
Which set of pictures below best represents a 1s, 2s and 3s orbital in that order?
Draw a Lewis dot structure for carbon monoxide gas, CO. Which of the following is true for the bond between the carbon and oxygen atoms?
It is a triple, polar, covalent bond.
If it took visible light 125 days to reach the earth from a star, how far away is that star from earth in miles?
2.02 x 1012 miles
Which of the following elements would most likely form a 1- anion?
Chlorine
A sample of 5.43 moles of gas has it’s pressure doubled from 2.00 atm to 4.00 atm while maintaining constant temperature. Which of the following will be true about the volume of the gas after the pressure increase if the initial volume is 60.8 L?
The final volume will be 30.4 L.
Pick the element below that has 7 valence electrons.
Fluorine
When a central atom has 4 structural pairs, what is the structural pair geometry?
Tetrahedral
The reaction 2A(g) + B(g) « 3C(g) + D(g) is at equilibrium. A is added to disturb the equilibrium. How do the concentrations of the other species shift to reestablish equilibrium?
Decrease [B] and increase [C] and [D].
Pick the list of ions given in decreasing strength as oxidizing agents (best oxidizing agent first) assuming that all ions are present at 1 M concentrations and get reduced to the corresponding elements.
A) Ag+(aq)>Cu2+(aq)>H+(aq)>Al3+(aq)
Pick the answer that has the correct noble gas core electronic configuration for As.
[Ar]4s23d104p3
Select the reaction below which would be predicted to have the largest increase in entropy.
2NH4NO3(s) ® 2N2(g) + 4H2O(g) + O2(g)
Acetylene gas (C2H2) reacts with hydrogen gas to form ethane gas (C2H6). Calculate the DG° for the reaction of one mole of acetylene gas. (DGf°(C2H2(g)) = 209.2 kJ/mol, DGf°(C2H6(g)) = -32.82 kJ/mol )
–242.0 kJ
An air bubble has a volume of 10.0 mL 200 feet under the water, pressure of 6.90 atm. What will the volume of this bubble be when it reaches the surface, pressure of 1.00 atm?
69.0 mL
An aqueous solution of urea (CO(NH2)2) has a urea mole fraction of 0.20. Compared to the vapor pressure of pure water at 25 °C, the vapor pressure of this solution at the same temperature, expressed as a percentage of the vapor pressure of pure water, will be:
80%
Which statement best describes what happens to Na when added to water?
Na reacts rapidly
How many oxygen atoms are in 4.00 moles of oxygen molecules?
4.82 x 1024 O atoms
Which of the following is a strong acid?
HCl