CHEM CH 13

Which of the following statements correctly describe solutions consisting of gases and/or solids? Select all that apply.

-A gas may dissolve in a solid by occupying the spaces between the solid particles. -Gas-gas solutions form readily because all gases are miscible with each other. -Gas-solid solutions are important as catalysts. Not correct: Solid-solid solutions cannot form because the mixture of two solids will always be heterogeneous; solids can be melted and mixed

Which of the following statements correctly relate the charge density of an ion to heat of hydration? Select all that apply.

-As the charge on an ion increases and its radius decreases, its charge density will increase and so will the magnitude of the heat of hydration. -An ion with a higher charge density has a more negative heat of hydration than an ion of similar size but lower charge.

Which of the following statements correctly describe different types of mixtures? Select all that apply.

-Differences in particle size account for the main differences between solutions and colloids. -A heterogeneous mixture contains two or more different phases. -The composition of any mixture is variable. Not correct: The phases of a heterogeneous mixture are always visibly distinct; some mixtures will have very small particles that aren't visible A colloid is a type of solution; a colloid is a heterogenous mixture unlike a solution which is homogenous

Which of the following statements correctly describe entropy? Select all that apply.

-Entropy is related to the freedom of motion of the particles in a system. -The entropy of a gas is higher than the entropy of a liquid. -Entropy is related to the number of ways a system can disperse its energy.

Which of the following statements correctly describe the molality and molarity of a solution?

-For a dilute aqueous solution molality and molarity are nearly equal. -Both molarity and molality express concentration in terms of moles of solute. -M must be calculated using the volume of the solution, not the volume of the solvent.

Which of the following options describe situations in which hydrogen bonding will be observed between the solute and the solvent? Select all that apply.

-Solvent contains N, O, or F; solute contains OH or NH groups. -Solvent contains OH or NH groups, solute contains N, O, or F atoms. -Solvent and solute both contain OH or NH groups.

Which step(s), involved in the formation of a solution, is/are associated with a positive sign for ΔH? Select all that apply.

-Solvent particles separate from each other. -Solute particles separate from each other. Not correct: -Solute and solvent particles mix to form a solution; here, energy is released - Solute and solvent particles attract each other; here, energy is released

Which of the following statements correctly describe the enthalpy changes associated with the formation of a solution? Select all that apply.

-The overall enthalpy change for the solution process depends on the balance of energy absorbed vs. energy released. -Energy is released when the solvent and solute particles attract each other and mix to form a solution. -Energy is absorbed to separate the solvent particles from each other.

Which of the following options correctly describe a solution that is in contact with undissolved solute at a given temperature?

-The rate at which solute is dissolving is equal to the rate at which solute particles are crystallizing from solution. -The concentration of dissolved solute will not change. -Undissolved solute is in equilibrium with dissolved solute.

I2 (s) has a very low solubility in H2O (l) because the weak _____ forces between I2 and H2O are not strong enough to replace the _____ between the H2O molecules.

1. dipole-induced dipole 2. hydrogen bonds

If more solute is added to a solvent, more than is able to dissolve at a given temperature, a(n) _____ will be established between dissolved and undissolved solute. The rate at which solute continues to dissolve is _____ to/than the rate at which solute crystallizes from solution.

1. equilibrium 2. equal

A solution forms when the attractive _____ between the solute and solvent are _____ in strength to the solvent-solvent and solute-solute attractions and are therefore able to replace them.

1. forces 2. similar

Entropy (S) is related to the _____ of movement of the particles in a system. The particles of a solid are highly ordered and therefore have _____ freedom of movement than the particles of a liquid. A liquid has _____ entropy than a solid.

1. freedom 2. less 3. more

Henry's law states that the solubility of a ______ in a solvent is directly proportional to the ______. Multiple choice question.

1. gas 2. pressure of that gas above the solution

The charge density of an ion has a significant effect on its heat of hydration. The _____ the charge on an ion and the _____ its size, the greater its attraction to the H2O molecules surrounding it and the more _____ the value of ΔHhydr of the ion.

1. higher 2. smaller 3. negative

Most solids are _____ soluble in a particular solvent at higher temperatures than at lower temperatures, although there are some exceptions. The solubility of a gas in water will generally _____ as temperature increases.

1. more 2. decrease

The most abundant component of a solution is usually called the ________ , whereas the other dissolved components are called __________.

1. solvent 2. solute

Intermolecular force: ion-dipole force

An ionic solute in a polar solvent

Intermolecular force: dispersion forces

Present in all solutions; principal intermolecular force when both solvent and solute are non-polar

Solvent

The component present in the largest amount

Solute

The component present in the smallest amount

Solubility

The maximum amount of a solute that can dissolve in a fixed quantity of a particular solvent at a given temperature

Miscible

The substances are soluble in each other at any quantity

True or false: All gases are miscible with each other.

True

A solution is a _____ mixture, meaning it exists in one phase, whereas a colloid is a _____ mixture with two or more phases in its composition.

homogenous; heterogenous

parts by mass

mass of solute/mass of solution

Mole fraction

mol of solute/ total number of moles present

Molarity (M)

mol of solute/L of solution

Molality (m)

mol of solute/kg of solvent

Intermolecular force: dipole-induced dipole forces

non-polar solute in a polar solvent

Intermolecular force: Ion-induced dipole forces

non-polar solute in a polar solvent that also contains dissolved ions