Question 1

At 20°C and 0.28 atm pressure Xenon has a solubility in water of 1.4 mmol/L.What is the Henry's Law-constant in mol/ L·atm at 20°C?

Accepted Answer

The answer of At 20°C and 0.28 atm pressure Xenon...

Question 2

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?

Accepted Answer

A) 0.1775 m H2SO4 
B) 0.1810 m H2SO4 
C) 1.810 m H2SO4 
D) 1.940 m H2SO4 
A) 0.1775 m H2SO4 
B) 0.1810 m H2SO4 
C) 1.810 m H2SO4 
D) 1.940 m H2SO4

Question 3

What is the expected freezing point of a 0.50 m solution of Na2CO3 in water? Kf for water is 1.86°C/m.

Accepted Answer

A) -0.93°C 
B) -1.9°C 
C) -2.8°C 
D) -6.5°C 
A) -0.93°C 
B) -1.9°C 
C) -2.8°C 
D) -6.5°C

Question 4

The number of moles of ions in 35.0mL of 4.00 M Na2SO4 is ________ moles.

Accepted Answer

Question 5

At 80.0°C benzene has a vapor pressure of 96.0 mm Hg and toluene has a vapor pressure of 30.3 mm Hg.If a mixture of benzene and toluene has a vapor pressure of 54.6 mm Hg,what are the mole fractions of benzene and toluene?

Accepted Answer

The answer of At 80.0°C benzene has a vapor pressure...

Question 6

What is the weight percent of a caffeine solution made by dissolving 4.35 g of caffeine,C8H10N4O2,in 75 g of benzene,C6H6?

Accepted Answer

A) 0.055% 
B) 0.058% 
C) 5.5% 
D) 5.8% 
A) 0.055% 
B) 0.058% 
C) 5.5% 
D) 5.8%

Question 7

In most liquid solutions,the component present in the larger amount is called the

Accepted Answer

A) dispersed medium. 
B) emulsifying agent. 
C) solute. 
D) solvent. 
A) dispersed medium. 
B) emulsifying agent. 
C) solute. 
D) solvent.

Question 8

For the process of dissolving a solid in a liquid,which of the following statements is true?

Accepted Answer

A) ΔHsoln is always negative and ΔSsoln is usually positive. 
B) ΔHsoln is always positive and ΔSsoln is usually negative. 
C) ΔHsoln is either positive or negative and ΔSsoln is usually positive. 
D) ΔHsoln is either positive or negative and ΔSsoln is usually negative. 
A) ΔHsoln is always negative and ΔSsoln is usually positive. 
B) ΔHsoln is always positive and ΔSsoln is usually negative. 
C) ΔHsoln is either positive or negative and ΔSsoln is usually positive. 
D) ΔHsoln is either positive or negative and ΔSsoln is usually negative.

Question 9

Which ion-dipole interaction results in the larger (more negative)hydration energy?

Accepted Answer

A) diagram (a) 
B) diagram (b) 
C) diagram (c) 
D) diagram (d) 
A) diagram (a) 
B) diagram (b) 
C) diagram (c) 
D) diagram (d)

Question 10

A KCl solution is prepared by dissolving 25.0 g KCl in 250.0 g of water at 25°C.What is the vapor pressure of the solution if the vapor pressure of water at 25°C is 23.76 mm Hg?

Accepted Answer

A) 21.6 mm Hg 
B) 22.7 mm Hg 
C) 23.2 mm Hg 
D) 24.9 mm Hg 
A) 21.6 mm Hg 
B) 22.7 mm Hg 
C) 23.2 mm Hg 
D) 24.9 mm Hg

Question 11

Aqueous solutions of 30% (by weight)hydrogen peroxide,H2O2,are used to oxidize metals or organic molecules in chemical reactions.Given that the density of the solution is 1.11 g/mL,calculate the molarity.

Accepted Answer

A) 0.794 M 
B) 6.78 M 
C) 9.79 M 
D) 12.6 M 
A) 0.794 M 
B) 6.78 M 
C) 9.79 M 
D) 12.6 M

Question 12

Drawing (1)shows a system in which an equilibrium exists between dissolved and undissolved gas particles at P = 1 atm.According to Henry's law,if the pressure is increased to 2 atm and equilibrium is restored,which drawing (2)-(5)best represents the equilibrium at 2 atm?

Accepted Answer

A) drawing (2) 
B) drawing (3) 
C) drawing (4) 
D) drawing (5) 
A) drawing (2) 
B) drawing (3) 
C) drawing (4) 
D) drawing (5)

Question 13

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.

Accepted Answer

A) -2.61°C 
B) 2.61°C 
C) 2.89°C 
D) 8.39°C 
A) -2.61°C 
B) 2.61°C 
C) 2.89°C 
D) 8.39°C

Question 14

Arrows in the energy diagram below represent enthalpy changes occurring in the endothermic formation of a solution:
ΔHS1U1B1solnS1U1B0 = enthalpy of solution
ΔHS1U1B1solute-soluteS1U1B0 = enthalpy change involving solute-solute interactions
ΔHS1U1B1solute-solventS1U1B0 = enthalpy change involving solute-solvent interactions
ΔHS1U1B1solvent-solventS1U1B0 = enthalpy change involving solvent-solvent interactions  
-Which arrow represents ΔHsolute-solvent?

Accepted Answer

A) arrow (a) 
B) arrow (b) 
C) arrow (c) 
D) arrow (d) 
A) arrow (a) 
B) arrow (b) 
C) arrow (c) 
D) arrow (d)

Question 15

In general,as the temperature increases,the solubility of gases in water ________ and the solubility of most solids in water ________.

Accepted Answer

A) decreases,decreases 
B) decreases,increases 
C) increases,decreases 
D) increases,increases 
A) decreases,decreases 
B) decreases,increases 
C) increases,decreases 
D) increases,increases

Question 16

The change in the Gibbs free energy for dissolving solute in a saturated solution is

Accepted Answer

A) negative. 
B) zero. 
C) positive. 
D) positive at low temperatures and negative at high temperatures. 
A) negative. 
B) zero. 
C) positive. 
D) positive at low temperatures and negative at high temperatures.

Question 17

Which of the following mixtures have components which can be separated by filtration?

Accepted Answer

A) colloids 
B) solutions 
C) suspensions 
D) all of these 
A) colloids 
B) solutions 
C) suspensions 
D) all of these

Question 18

The dose of amoxicillin given to a young child is 40.0 mg/kg of body weight/day.If the amoxicillin is administered as a suspension having a concentration of 400.mg/5 mL,how many mL of amoxicillin must be administered per dose for a child weighing 30.0 pounds?

Accepted Answer

A) 3.00 mL 
B) 6.82 mL 
C) 16.0 mL 
D) 9.9 mL 
A) 3.00 mL 
B) 6.82 mL 
C) 16.0 mL 
D) 9.9 mL

Question 19

A phase diagram of temperature versus composition for a mixture of the two volatile liquids octane (bp =   and decane (bp = 126°C)is shown.  
-Assume that the vapor at point c is condensed and reboiled.What is the vapor composition during reboiling?

Accepted Answer

A) 100% decane 
B) composition at point b 
C) composition at point c 
D) composition at point e 
A) 100% decane 
B) composition at point b 
C) composition at point c 
D) composition at point e

Question 20

Sodium hydroxide is available commercially as a 50.0% by weight aqueous solution.The density of the solution is 1.53 g/mL.Calculate the molarity of this sodium hydroxide solution.

Accepted Answer

A) 0.450 M 
B) 19.1 M 
C) 25.0 M 
D) 125.M 
A) 0.450 M 
B) 19.1 M 
C) 25.0 M 
D) 125.M

Exam 12: Solutions and Their Properties

At 20°C and 0.28 atm pressure Xenon has a solubility in water of 1.4 mmol/L.What is the Henry's Law-constant in mol/ L·atm at 20°C?

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?

What is the expected freezing point of a 0.50 m solution of Na2CO3 in water? Kf for water is 1.86°C/m.

The number of moles of ions in 35.0mL of 4.00 M Na2SO4 is ________ moles.

At 80.0°C benzene has a vapor pressure of 96.0 mm Hg and toluene has a vapor pressure of 30.3 mm Hg.If a mixture of benzene and toluene has a vapor pressure of 54.6 mm Hg,what are the mole fractions of benzene and toluene?

What is the weight percent of a caffeine solution made by dissolving 4.35 g of caffeine,C8H10N4O2,in 75 g of benzene,C6H6?

In most liquid solutions,the component present in the larger amount is called the

For the process of dissolving a solid in a liquid,which of the following statements is true?

Which ion-dipole interaction results in the larger (more negative)hydration energy?

A KCl solution is prepared by dissolving 25.0 g KCl in 250.0 g of water at 25°C.What is the vapor pressure of the solution if the vapor pressure of water at 25°C is 23.76 mm Hg?

Aqueous solutions of 30% (by weight)hydrogen peroxide,H2O2,are used to oxidize metals or organic molecules in chemical reactions.Given that the density of the solution is 1.11 g/mL,calculate the molarity.

Drawing (1)shows a system in which an equilibrium exists between dissolved and undissolved gas particles at P = 1 atm.According to Henry's law,if the pressure is increased to 2 atm and equilibrium is restored,which drawing (2)-(5)best represents the equilibrium at 2 atm?

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.

In general,as the temperature increases,the solubility of gases in water ________ and the solubility of most solids in water ________.

The change in the Gibbs free energy for dissolving solute in a saturated solution is

Which of the following mixtures have components which can be separated by filtration?

The dose of amoxicillin given to a young child is 40.0 mg/kg of body weight/day.If the amoxicillin is administered as a suspension having a concentration of 400.mg/5 mL,how many mL of amoxicillin must be administered per dose for a child weighing 30.0 pounds?

A phase diagram of temperature versus composition for a mixture of the two volatile liquids octane (bp = and decane (bp = 126°C)is shown. -Assume that the vapor at point c is condensed and reboiled.What is the vapor composition during reboiling?

Sodium hydroxide is available commercially as a 50.0% by weight aqueous solution.The density of the solution is 1.53 g/mL.Calculate the molarity of this sodium hydroxide solution.

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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?

What is the expected freezing point of a 0.50 m solution of Na₂CO₃ in water? K_f for water is 1.86°C/m.

The number of moles of ions in 35.0mL of 4.00 M Na₂SO₄ is ________ moles.

What is the weight percent of a caffeine solution made by dissolving 4.35 g of caffeine,C₈H₁₀N₄O₂,in 75 g of benzene,C₆H₆?

Aqueous solutions of 30% (by weight)hydrogen peroxide,H₂O₂,are used to oxidize metals or organic molecules in chemical reactions.Given that the density of the solution is 1.11 g/mL,calculate the molarity.

Calculate the freezing point of a solution of 50.0 g methyl salicylate,C₇H₆O₂,dissolved in 800.g of benzene,C₆H₆.K_f for benzene is 5.10°C/m and the freezing point is 5.50°C for benzene.

In general,as the temperature increases,the solubility of gases in water and the solubility of most solids in water .