Chem II Chapter 13 homework

B

A solution is saturated with both a solid and a gas at 85°C. What is likely to happen if the solution is cooled to 5°C? A: some gas will bubble out of the solution B: some solid will precipitated out of the solution C: some gas will bubble out of the solution and some solid will precipitate out of the solution

C

A student working on a laboratory experiment dissolves a hypothetical solute AB in water. The student observes that the flask becomes cold to the touch. The enthalpy value for this reaction is positive. Using the diagram determine which situation result in a positive ΔHsoln. A: less than solute-solvent interactions B: equal to the solute-solvent interactions C: greater than the solute-solvent interactions

A

A student working on a laboratory experiment dissolves a hypothetical solute AB in water. The student observes that the flask becomes cold to the touch. Use the diagram to determine which of the following equations accurately shows the relationship between the magnitude of the enthalpy values for each step in the dissolution of AB in water for a flask that becomes cold to the touch. A: ΔH1 + ΔH2 > ΔH3 B: ΔH1 + ΔH2 = ΔH3 C: ΔH1 + ΔH2 < ΔH3

C

A student working on a laboratory experiment dissolves a hypothetical solute AB in water. The student observes that the flask becomes cold to the touch. What direction does energy flowing in the system as solute AB dissolves in water? A: Energy is flowing out of the system into the surroundings. B: Energy is in equilibrium between the system and the surroundings. C: Energy is flowing into the system from the surroundings.

C

A KNO3 solution containing 49 g of KNO3 per 100.0 g of water is cooled from 44°C to 0°C. What happens during cooling? A: at 44°C the solution is saturated, and to reach 0°C the solution would be supersaturated; therefore a precipitate will form. B: at 44°C the solution unsaturated, and at 0°C the solution is also unsaturated; therefore no precipitate will form. C: at 44°C the solution is unsaturated, but by 0°C the solution is saturated; therefore a precipitate will form. D: at 44°C the solution is supersaturated; therefore a precipitate will form upon cooling. E: at 44°C the solution is supersaturated, but by 0°C the solution is unsaturated; therefore no precipitate

A

A certain ionic compound has a ΔH soln = -65.4 kJ/mol. Which of the following conclusions is correct? A: ΔHsolute < ΔHmix B: ΔHsolute ≈ ΔHmix C: ΔHsolute ≈ 0, ΔHmix <0 D: ΔHsolute > ΔHmix

A, C, D

Identify the kind of intermolecular forces that would occur between the solute and solvent in Ethanol (polar; contains an OH group) A: dipole-dipole B: ion-dipole C: hydrogen bonding D: dispersion

D

Identify the kind of intermolecular forces that would occur between the solute and solvent in Lard (nonpolar) A: dipole-dipole B: ion-dipole C: hydrogen bonding D: dispersion

D

Identify the kind of intermolecular forces that would occur between the solute and solvent in Motor oil (nonpolar) A: dipole-dipole B: ion-dipole C: hydrogen bonding D: dispersion

B, D

Identify the kind of intermolecular forces that would occur between the solute and solvent in Potassium chloride (ionic) A: dipole-dipole B: ion-dipole C: hydrogen bonding D: dispersion

A

The overall enthalpy change upon solution formation is called _______ A: ΔHsoln B: ΔHlattice C: ΔHsolvent D: ΔHmix E: ΔHhydration

D

To make a 2.00 m solution one could take 2.00 moles of solute and add: A: enough solvent to make 1.00 L of solution B: 1.00 L of solvent C: enough solvent to make 1.00 kg of solution D: 1.00 kg of solvent

C

When a beaker is heated, what direction is energy moving? A: Energy is released from the system when a beaker is heated. B: Energy does not flow between systems. C: Energy is entering the system when a beaker is heated.

C

When ammonia gas is dissolved in water, a basic solution of "ammonium hydroxide" (NH4+(aq) and OH− (aq)) forms. Which of the following correctly describes the solubility of ammonia in water? A: A decrease in solubility with increasing amount of solvent B: A decrease in solubility with increasing ammonia pressure C: An unusually large Henry's law constant D: decrease in solubility with decreasing temperature

A

Which of the following accurately defines an exothermic process? A: an exothermic process releases heat into the surroundings. B: an exothermic process does not exchange heat with the surroundings. C: an exothermic process absorbs heat from the surroundings.

C

Which of the following concentration units or temperature dependent? A: mole fraction B: mass percent C: Molarity D: molality E: none of the above

Polar

Polar solvents tend to dissolve _____ solutes

D

Predict what must happen when a beaker containing a solution of lithium chloride is heated. Check all that apply: A: the ΔH3 value will increase B: The reaction will become endothermic C: the ΔHsoln value will decrease D: Energy will be transferred into the system

C > B > D > A

Rank the following substances in order from most soluble in water to least soluble in water: A: ethane (C2H6) B: 2-pentanol (C5H11OH) C: copper(II) sulfate (CuSO4) D: propane (C3H8)

1, 5, 6

Select the appropriate solvent from the table to dissolve kerosene (nonpolar). 1: toluene 2: acetone 3: methanol 4: water 5: carbon tetrachloride 6: hexane 7: ethanol

1, 5, 6

Select the appropriate solvent to dissolve Lard (nonpolar) 1: toluene 2: acetone 3: methanol 4: water 5: carbon tetrachloride 6: hexane 7: ethanol

2, 3, 4

Select the appropriate solvents from the table to dissolve ethylene glycol (polar; contains an OH group) 1: toluene 2: acetone 3: methanol 4: water 5: carbon tetrachloride 6: hexane 7: ethanol

2, 3, 4, 7

Select the appropriate solvents from the table to dissolve lithium nitrate (ionic) 1: toluene 2: acetone 3: methanol 4: water 5: carbon tetrachloride 6: hexane 7: ethanol

A, b

Select the steps that are associated with energy entering the system. Check all that apply: a. the separation of solvent molecules b. the separation of solute molecules c. the mixing of solute and solvent molecules

A

which substance is the least hydrophilic (most hydrophobic)? A: ethane B: 2-pentanol C: copper(II) sulfate D: propane

C

which substance is the most hydrophilic? A: ethane B: 2-pentanol C: copper(II) sulfate D: propane

B

A solution is an equimolar mixture of two volatile components A and B (relative to those between particles of A and those between particles of B)? A: The intermolecular forces between particles A and B are weaker than those between particles of A and those between particles of B. B: The intermolecular forces between particles A and B are stronger than those between particles of A and those between particles of B C: The intermolecular forces between particles A and B are the same as those between particles of A and those between particles of B D: nothing can be concluded about the relative strength of intermolecular forces from this observation

C

An equal solution is in equilibrium with a gaseous mixture containing an equal number of moles of helium, carbon dioxide, and nitrogen. Rank the relative concentrations of each gas in the aqueous solution from highest to lowest: A: [CO2] > [He] > [N2] B: [He] > [N2] > [CO2] C: [CO2] > [N2] > [He] D: [N2] > [CO2] > [He]

D

Choose the aqueous solution with the lowest vapor pressure. These are all solutions of nonvolatile solutes and you should assum ideal van't Hoff factors where applicable. A: .040 m (NH4)2SO4 B: .030 m RbC2H3O2 C: .120 m C2H6O2 D: .060 m Li2CO3 E: they all have the same vapor pressure

A, D, F

Choose which of the following expressions describes correctly the relations between the ΔH values. Select all that apply: A: ΔHsoln = ΔHsolvent + ΔHmix - ΔHlattice B: ΔHsoln = ΔHsolvent + ΔHmix + ΔHlattice C: ΔHhydratjon = ΔHsolvent - ΔHmix (for aqueous solutions) D: ΔHsolute = -ΔHlattice (for ionic compounds) E: ΔHsolute = ΔHlattice (for ionic compounds) F: ΔHhydration = ΔHsolvent + ΔHmix (for aqueous solutions)

Surroundings, system, higher, exothermic, faster, gained

In the calorimeter, water is the ______. The salt LiCl, which will dissolve, is the _____. The final temperature of the water after the dissolution of LiCl was ______ than the initial temperature, meaning the process is ______. In the microscopic view of the dissolution of LiCl, water molecules were seen to move ____ as they ______ energy. - Gained - system - faster - surroundings - lost - higher - slower - endothermic - exothermic - lower

A

In which of the following types of solution is the rate of dissociation equal to the rate of crystallization? A: saturated B: concentrated C: supersaturated D: unsaturated

Nonpolar, nonpolar

Motor oil is ______, and thus it will require a _____ solvent

Nonpolar

Non-polar solvents tend to dissolve _____ solutes

A

Of the following solutions, which will have the highest boiling point? A: .30 m Na2SO4 B: .30 m NaBr C: .50 m C6H12O6 D: .20 m Al(NO3)3

C, D (exothermic processes are associated with a negative ΔH value)

The chemical equation for the dissolution of lithium chloride LiCl is: LiCl(s)+H2O=Li+(aq)+Cl-(aq) The ΔH value for this process is -37.4 kJ/mol. Select the ΔH values associated with the dissolution of lithium chloride that are exothermic. A: ΔH1 = Energy associated with the separation of water molecules B: ΔH2 = Energy associated with the separation of LiCl ions C: ΔH3 = Energy associated with the formation of water-ion interactions D: ΔHsoln = The enthalpy of solution

D

The energy of mixing solute particles in solvent particles is called _______ and is always exothermic. A: ΔHsoln B: ΔHlattice C: ΔHsolvent D: ΔHmix E: ΔHhydration

C

The energy required to separate solvent particles is called ________ and is always endothermic. A: ΔHsoln B: ΔHlattice C: ΔHsolvent D: ΔHmix E: ΔHhydration

Negative, less than

The enthalpy of solution for CaCl2 has a _____ sign; therefore, the total enthalpy associated with the breaking of solute-solute and solvent-solvent interactions must be ____ the enthalpy associated with the solute-solvent interactions.

Negative, exothermic, less than

The enthalpy of solution for KOH has a _____ sign; therefore, the formation of the solution is _____, and the enthalpy associated with breaking the solute-solute and solvent-solvent interactions must be _____ The enthalpy associated with forming solute-solvent interactions. - positive - greater than - endothermic - negative - exothermic - less than

Positive, endothermic, greater than

The enthalpy of solution for NH4NO3 has a ____ sign; therefore, the formation of the solution is ____ and the sum of the enthalpy associated with solute-solute and solvent-solvent interactions must be _____ the enthalpy of solute-solvent interaction. - positive - greater than - endothermic - negative - exothermic - less than

B

______ is the enthalpy change during the formation of the crystalline solid from the gaseous ions. A: ΔHsoln B: ΔHlattice C: ΔHsolvent D: ΔHmix E: ΔHhydration

E

______ is the enthalpy change that occurs when one mole of the gaseous solute ions is dissolved in water. A: ΔHsoln B: ΔHlattice C: ΔHsolvent D: ΔHmix E: ΔHhydration

D

choose the aqueous solution has the highest boiling point. These are all solutions of non-volatile solutes and you should assume ideal van't Hoff factors where applicable A: .100 m KNO2 B: .060 m LiPO4 C: .200 m C3H8O3 D: .100 m Li2SO4 E: they all have the same boiling point