CHM 123Extra Credit - Final ReviewName
Due on the FINAL EXAM DAY for 10 extra credit points to Masteringchemistry HW, no late assignment will be accepted!!!!!!
It is the students’ responsibility to review and study all other topics that were discussed in class. Do NOT assume the exam will only have these particular questions.
Chapter 7-8, 11
Which drawing best accounts for the polarity of methanol, CH3OH, and the bond polarities that make a major contribution to the overall molecular polarity?
Use the diagram below to answer the following questions.
Melting occurs along the ……..
The solid and liquid phases can exist in equilibrium along line ………..
The temperature and pressure at which all three phases can coexist in equilibrium is ……..
From the phase diagram above, the minimum pressure at which this substance can exist in the liquid phase is ……..
The normal boiling point of this substance is approximately …..
What phases can be present at 200°C and 0.75 atm pressure?
What phase changes occur when the temperature is held constant at 140°C and the pressure is increased from 0.25 atm to 1.4 atm?
What phase changes occur when the pressure is held constant at 0.25 atm and the temperature increases from 100°C to 300°C?
Chapter 12
One reason ionic compounds do not dissolve well in nonpolar solvents is that
A) ion-dipole interactions are too large for effective solvation to occur.
B) ion-solvent interactions are not strong enough to solvate the ions in solution.
C) not all cations and anions have the same magnitude of charge and therefore do not form neutral ion pairs.
D) there are no forces of attraction between ions and nonpolar molecules.
In general, as the temperature increases, the solubility of gases in water ______and the solubility of most solids in water ______.
A) decreases, decreases
B) decreases, increases
C) increases, decreases
D) increases, increases
The solubility of argon in water at 25°C is 0.0150 mol/L. What is the Henry's Law constant for argon if the partial pressure of argon in air is 0.00934 atm?
A) 1.40 × 10-4 mol/(L ∙ atm)
B) 0.623 mol/(L ∙ atm)
C) 1.61 mol/(L ∙ atm)
D) 4.10 mol/(L ∙ atm)
Answer: C
What is the mole fraction of ethanol in a solution made by dissolving 14.6 g of ethanol, C2H5OH, in 53.6 g of water?
Answer: 0.0964
A solution is prepared by dissolving 17.75 g sulfuric acid, H2SO4, in enough water to make 100.0 mL of solution. If the density of the solution is 1.1094 g/mL, what is the molality?
Answer: 1.940 m H2SO4
A solution is prepared by dissolving 17.75 g sulfuric acid, H2SO4, in enough water to make exactly 100.0 mL of solution. If the density of the solution is 1.1094 g/mL, what is the weight % H2SO4 in the solution?
Answer: 16.00%
A solution is 2.25% by weight NaHCO3. How many grams of NaHCO3 are in 450.0 g of solution?
Answer: 10.1 g
The solubility of argon in water at 25°C is 0.0150 mol/L. What is the Henry's Law constant for argon if the partial pressure of argon in air is 0.00934 atm?
Answer: 1.61 mol/(L ∙ atm)
Indicate how many particles are formed when the following solutes dissolve.
solute / # of particles / solute / # of particlessucrose (C12H22O11) / magnesium chloride (MgCl2)
sodium sulfate (Na2SO4) / methanol (CH3OH)
Calculate the freezing point of a solution of 50.0 g methyl salicylate, C7H6O2, dissolved in 800. g of benzene, C6H6. Kf for benzene is 5.10°C/m and the freezing point is 5.50°C for benzene.
2.89°C
The molal boiling point constant for ethyl alcohol is 1.22 oC/molal. Its boiling point is 78.4oC. A solution of 14.2 g of a nonvolatile nonelectrolyte in 264 g of the alcohol boils at 79.8oC. What is the molecular mass of the solute?
A solution of 0.2113 g of water dissolved in 25.0 g of a solvent freezes at 11.5°C below the freezing point of the solvent. What is Kf for this solvent?
24.5°C/m
125 g of the non-volatile solute glucose, C6H12O6, is dissolved in 125 g of water at 25.0oC. IF the vapor pressure of water at 25.0oC is 23.7 Torr, what is the vapor pressure of the solution?
Calculate the Osmotic pressure at 50 degrees Celsius of a glucose solution C6H12O6 that has 60 grams of glucose dissolved in enough water to make 1500 ml.
answer: 5.89 atm
What is the expected freezing point of a 0.50 m solution of Na2CO3 in water? Kf for water is 1.86°C/m.
-2.8°C
Chapter 13
A concentration-time study of the gas phase reaction 2 A3 → 3 A2 produced the data in the table below.
A concentration-time study of the gas phase reaction 2 A3 → 3 A2 produced the data in the table below
Time (s)[A3] (M)[A2] (M)
04.00 × 10–40
102.00 × 10–43.00 × 10–4
201.00 × 10–44.50 × 10–4
305.00 × 10–5…………
What is the average rate of formation of A2 in the time interval 20-30 seconds?
Answer: 7.50 × 10–6 M/s
The following set of data was obtained by the method of initial rates for the reaction:
(H3C)3CBr + OH- → (H3C)3COH + Br-
What is the order of reaction with respect to ion, OH-?
[(H3C)3CBr] (M)[OH ] (M)Initial Rate (M/s)
0.250.251.1 × 10–4
0.500.252.2 × 10–4
0.500.502.2 × 10–4
Answer: zero
The first-order reaction, SO2Cl2 → SO2+ Cl2, has a rate constant equal to 2.20 × 10-5 s-1 at 593 K. What percentage of the initial amount of SO2Cl2 will remain after 2.00 hours?
Answer: 85.4%
The equation of tris(1, 10-phenanthroline)iron(II) in acid solution takes place according to the equation:
Fe(phen)32+ + 3 H3O+ + 3 H2O → Fe(H2O)62+ + 3 phenH+
If the activation energy is 126 kJ/mol and frequency factor is 8.62 × 1017 s-1, at what temperature is the rate constant equal to 3.63 × 10-3 s-1 for the first-order reaction?
Answer: 50°C
The first-order isomerization reaction: cyclopropane → propene, has a rate constant of 1.10 × 10–4 s–1 at 470°C and 5.70 × 10–4 s–1 at 500ºC. What is the activation energy, Ea, for the reaction?
Answer: 260 kJ/mol
Chapter 16
What is the approximate pH at the equivalence point of a weak acid-strong base titration if 25.0 mL of aqueous hydrofluoric acid requires 30.00 mL of 0. 400 M NaOH? Ka = 6.76 × 10-4 for HF.
Answer: 8.25
What is the pH of the resulting solution if 45.0 mL of 0.432 M methylamine, CH3NH2, is added to 15.0 mL of 0.234 M HCl? Assume that the volumes of the solutions are additive. Ka = 2.70 × 10-11 for CH3NH3+.
Answer: 11.23
Chapter 19
C has a decay constant, k = 1.209 × 10–4 yr–1 and a half-life of _____ years.
Answer: 5.733 × 103
Neptunium-239 has a half-life of 2.35 days. How many days must elapse for a sample of 239Np to decay to 0.100% of its original quantity?
Answer: 23.4 days
If the age of the Earth is 4.5 billion years and the half-life of 40K is 1.26 billion years, what percent of the Earth's original amount of 40K remains today?
Answer: 8.4%
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