Abeka Chemistry Precision and Design Test 8 In order, all answers

What does the field of chemical kinetics involve?

a. reaction rates

b. reaction pathways

c. both a and b

d. neither a nor b

c. both a and b

What category includes emulsions, foams, sols, and gels?

a. solutions

b. suspension

c. colloids

d. solutes

c. colloids

What is a mixture containing tiny clumps or particles that remain suspended within the mixture and will not settle out?

a. solutions

b. suspension

c. colloids

d. solutes

c. colloid

Which of the following statements regarding catalysts is not true?

a. A catalyst increases the activation energy of a chemical reaction.

b. A catalyst increases the rate of a chemical reaction.

c.(triangle)H for catalyzed and uncatalyzed reactions is the same.

d. Catalysts may be classified as homogeneous and heterogeneous

a. A catalyst increases the activation energy of a chemical reaction.

What type of substance is the scattering of light known as the Tyndall effect a characteristic of?

a. solutions

b. colloids

c. solutes

d. supercritical fluids

b. colloids

Which of the following is true if two substances in the same phase are miscible?

a. They are completely soluble in each other.

b. They are partially soluble in each other.

c. They can be mixed together temporarily but settle out upon standing.

d. They do not dissolve in each other to any significant extent.

a. They are completely soluble in each other

When a liquid in a closed container reaches a state of equilibrium with its vapor, which of the following is true?

a. The number of molecules in the vapor state and liquid state are equal.

b. The number of molecules evaporating and condensing are equal.

c. The processes of evaporation and condensation have ceased.

d. The liquid is at the boiling point.

b. The number of molecules evaporating and condensing are equal.

What is the attraction of a substance to the surface of a solid called?

a. cohesion

b. adsorption

c. suspension

d. absorption

b. adsorption.

What is the total heat absorbed or released when one sustance dissolves in another?

a. enthalpy of formation

b. enthalpy of fusion

c. enthalpy of solution

d. enthalpy of dissolving

c. enthalpy of solution

When a solution reaches a state of equilibrium, why does the amount of undissolved solid remain constant?

a. The process of dissolution has ceased.

b. The rate of crystallization equals the rate of dissolution.

c. No more free solvent is available.

d. The solute contains an insoluble residue.

b. The rate of crystallization equals the rate of dissolution.

What do colligative properties primarily depend upon?

a. properties of the solute

b. concentration of the solution

c. pressure of the solution

d. temperature of the solution.

b. concentration of the solution

In a solution of glucose in water, what is the glucose?

a. solvent

b. suspension

c. colloid

d. solute

d. solute

How does increasing concentration usually affect the rate of a reaction?

a. Increases the rate of reaction by decreasing the repulsion between molecules

b. Increases the rate of reaction by increasing the frequency of collisions

c. Decreases the rate of reaction by increasing the repulsion between molecules

d. Decreases the rate of reaction by decreasing the frequency of collisions.

b. Increases the rate of reaction by increasing the frequency of collisions

A homogeneous mixture of two or more substances

I. Solution

A protein catalyst found in living things.

c. enzyme

A substance that slows the rate of a reaction.

F. Inhibitor

A series of steps describing the way in which a chemical reaction proceeds.

H. Reaction mechanism

A chemical reaction in which the products of one reaction step causes other reactions to occur.

A. Chain reaction

A reaction in a proposed series that has a greater activation energy than the others and thus occurs more slowly.

G. rate-determining step

The erratic movement of colloidal particles due to random molecular collisions that keep them suspended is known as @Brownian motion@.

True

Substances that dissolve in water to produce ions that can conduct an electrical current are called @colloids@.

False, electrolytes

The energy diagram below represents an @endothermic@ reaction.

False, exothermic

The minimum kinetic energy that a molecule must possess to undergo a chemical reaction is called @potential@ energy

False, activation

Tiny, emulsified droplets of grease or oil suspended in water by soap molecules are @micelles@.

True

A solution that contains as much dissolved solute as possible under equilibrium condition is @saturated@.

True

When two opposite processes continuously occur at equal rates so that they offset each other, the system is said to be in a state of @balanced@ equilibrium.

False, dynamic

An ion or molecule surrounded by water molecules in aqueous solution is @hydrated@.

True

The quantity of a solute for a given quantity of solution or solvent is known as @concentration@.

True

In a chemical reaction, the change in concentration of a substance divided by the time for the change is the reaction @rate@.

True

Which of the following best explains why a catalyst increases the rate of reaction?

a. It increases activation energy.

b. It makes the molecules collide less often.

c. It makes the molecules collide more often.

d. It reduces activation energy.

d. It reduces activation energy.

Which of the following best explains the meaning of the phrase "like dissolves like"?

a. Substances in the same state will dissolve in each other more readily.

b. Substances with similar moralities will dissolve in each other more readily.

c. Substances with similar intermolecular forces will dissolve in each other more readily.

d. Substances with similar electron configuration will dissolve in each other more readily.

c. Substances with similar intermolecular forces will dissolve in each other more readily.

At 30 degrees C, the rate of a particular reaction is 0.001 M/s: What is the rate expected to be at 60 degrees C, assuming all other factors remain the same?

a. 0.003 M/s

b.0.004 M/s

c. 0.016 M/s

d. 0.040 M/s

c. 0.016 M/s

Two compartments, labeled "A" and "B" are separated by a semipermeable membrane. What happens if compartment A is filled with honey ( a solution of sugar dissolved in water ) and compartment B is filled with distilled water?

a. There is a net transfer of sugar from A to B

b. There is a net flow of water from A to B.

c. There is a net transfer of sugar from B to A.

d. There is a net flow of water from B to A.

d. There is a net flow of water from B to A.

Which statement best explains why the following reaction is not likely to occur in a single step?

2C6H6(1)+ 15 O2(g)----> 12 CO2(g) + 6H2O(g)

a. Exothermic reactions typically require several steps.

b. Gases do not usually react directly with liquids or solids.

c. The 17-body collision required is extremely unlikely.

d. The reaction is spontaneous and is not reversible.

c. The 17-body collision required is extremely unlikely

Which of the following terms describes a platinum mesh used to break down petroleum vapor into smaller molecules?

a. Activated complex

b. Homogeneous catalyst

c. heterogenous catalyst

d. enzyme

c. heterogenous catalyst

Which of the following combinations is most likely to be cocmpletely miscible?

a. water and isopropyl alcohol

b. isopropyl alcohol and oil

c. water and oil

d. None will be completely miscible.

a. water and isopropyl alcohol

Which of the following is not necessarily true about the rate-determining step of a reaction?

a. The reaction can proceed no faster than the rate-determining step.

b. The rate-determining step is the slowest step of a multi step reaction.

c. The rate-determining step involves the greatest number of reacting species.

d. The rate-determining step should be the focus of any attempt to increase the reaction rate.

c. The rate-determining step involves the greatest number of reacting species.

Which of the following substances would you expect to be most soluble in a nonpolar solvent such as gasoline?

a. water (polar)

b. ammonia (polar)

c. paraffin (nonpolar)

d. All are equally soluble

c. paraffin (nonpolar)

Which of the following is not a colloid?

a. aerogel

b. milk

c. smoke

d. sugar water

d. sugar water

When a solid is dissolved in a liquid solvent, does increasing the temperature tend to increase or to decrease the solubility of a solid?

increase

When a gas is dissolved in a liquid solvent, does increasing the temperature tend to increase or to decrease the solubility of the gas?

decrease

What term refers to a solution that contains more solute than is ordinarily possible under equilibrium conditions?

supersaturated

Does adding a nonvolatile solute to a liquid tend to raise or to lower its boiling point?

raise

Name the short-lived, unstable arrangement of atoms that molecules are thought to form as they collide and chemically react.

activated complex

What term refers to a substance that increases the rate of a chemical reaction without being consumed in the reaction?

catalyst

Does increasing the temperature of a liquid tend to increase or decrease its vapor pressure?

increase

Does adding a nonvolatile solute to a liquid tend to increase or to decrease its vapor pressure?

decrease

Calculate the molarity of a solution prepared by dissolving 80 g hydrogen flouride in water to make a 500 mL of solution; the polar mass of HF is 20.01 g/mol.

80.0g

-------- =4.00 mol

20.01 g/mol

4.00 mol

----------- =8.00M

0.5000L

A chemist needs to prepare 2.50 L of 0.100 M ammonia. How much concentrated (14.8M) ammonia does he need?

(2.50 L)(0.100 M)

V1-------------------- = 0.0169 L=16.9 mL

14.8M

Determine the freezing point of a solution containing 50.0g of sucrose dissolved in 750 g water; round to the nearest 0.01 degrees

C. (KF for water is 1.86 degrees C/m, and the molar mass of sucrose is 342.3 g/mol.)

50.0g

------------= 0.146 mol

342.3 g/mol

0.146 mol

m=-------------= 0.195m

0.750 kg

triangle Tf = mKf=(0.195 m)(1.86 degrees C/m)= 0.363 degrees C

Tf= 0.00 degrees C - 0.363 degrees C = 0.36 degrees C

Essay

answers will vary.

*Henry's law states that the higher the partial pressure of a gas, the greater the solubility of the gas at a given temperature.

The lower atmospheric pressure at the top of Mt. Everest means that the partial pressure of CO2* in the air is lower.

The lower partial pressure of CO2 at higher altitude makes the gas less soluble in the liquid (according to henry's law); when the can is opened, more dissolved CO2* will come out of solution on top of MT. Everest than at sea level due to this decreased solubility.