Chemistry Flashcards on Thermodynamics and Reactions

As a general rule, the entropy of a solid is

A. less than that of a liquid.

B. more than that of a liquid.

C.more than that of a gas.

D. zero.

A. less than that of a liquid.

If the temperature of the equilibrium system CH,OH(g) + 101 kJ <-> CO(g) + 2H2(g) increases...

A. [CH,OH] increases and [CO] decreases.

B. [CH,OH] decreases and [CO] increases.

C. [CH,OH] increases and [CO] increases.

D. the concentrations in the system do not change.

B. [CH2OH] decreases and [CO] increases.

Two gases with unequal molar masses are injected into opposite ends of a long tube at

the same time and allowed to diffuse toward the center. They should begin to mix

A. in approximately five minutes.

B. closer to the end that holds the heavier gas.

C. closer to the end that holds the lighter gas

D. exactly in the middle.

C. closer to the end that holds the lighter gas.

A solute whose water solution conducts electricity is called a(n)

A. nonconductor.

B. electrolyte.

C. nonelectrolyte.

D. aqueous solution.

B. electrolyte.

A solution that has a pH of 4.0

A. is neutral.

B. is acidic.

C. is basic.

D. could be neutral, basic, or acidic.

B. is acidic.

In order for an endothermic reaction to occur spontaneously, what must happen?

A. The enthalpy must be negative.

B. The entropy must be positive.

C. The entropy must be negative.

D. The change in Gibbs free energy must be positive.

B. The entropy must be positive.

What impact does an increase in temperature generally have on the rate of a reaction?

A. It increases it.

B. It has no impact.

C. There is no way to measure the change.

D. It decreases it.

A. It increases it.

Why would a camper near the top of Mt. Everest find that water boils at less than 100%

A. There is greater atmospheric pressure than at sea level.

B. The flames are hotter at that elevation.

C. There is less atmospheric pressure than at sea level.

D. The atmosphere has less moisture.

C. There is less atmospheric pressure than at sea level.

A solid crystal is dropped into a solution containing dissolved solute. It falls to the bottom of the beaker and does not dissolve after vigorous stirring. What does this indicate about the solution?

A. It is probably unsaturated.

B. It is probably supersaturated.

C. It is probably saturated.

D. It is not at equilibrium.

C. It is probably saturated.

A solution has a hydronium ion concentration of 0.0001 M. Which statement is true about

its pH?

A. It will be in the basic range.

B. It will be in the acidic range.

C. It will be neutral.

D. It is not possible to determine without more information.

B. It will be in the acidic range.

Energy transferred as heat always moves spontaneously from matter

A. at a lower temperature to matter at a higher temperature.

B. at a higher temperature to matter at a lower temperature.

C. at an enthalpy of zero to matter with a negative enthalpy.

D. None of the above

B. at a higher temperature to matter at a lower temperature.

Catalysts affect reaction rates by

A. forming an activated complex with lower energy.

B. broadening the energy barrier.

C. increasing the activation energy.

D. changing the net thermodynamics of the reaction.

A. forming an activated complex with lower energy.

An acid-base titration involves a

A. composition reaction.

B. neutralization reaction.

C. single-replacement reaction.

D. decomposition reaction.

B. neutralization reaction.

A chemical change is likely to occur when

A. enthalpy and randomness both increase.

B. enthalpy and randomness both decrease.

C. enthalpy increases and randomness decreases.

D. enthalpy decreases and randomness increases.

D. enthalpy decreases and randomness increases.

During boiling, the temperature of a liquid

A. remains constant.

B. increases.

C. decreases.

D. approaches water's boiling point.

A. remains constant.

To be effective, a collision requires

A. sufficient energy.

B. a favorable orientation.

C. sufficient energy and a favorable orientation

D. a reaction mechanism.

C. Sufficient energy and a favorable orientation.

A chemical reaction that is at equilibrium always has

A. a high K value.

B. a forward reaction rate that equals the reverse reaction rate.

C. equal concentrations of reactants and products

D. Both (B) and (C)

B. A forward reaction rate that equals the reverse reaction rate.

At its triple point, water can

A. have only three pressure values.

B. exist in equilibrium in three different phases.

C. only be present as vapor.

exist only as a solid.

B. Exist in equilibrium in three different phases.

In a Bronsted-Lowry acid-base reaction, what are transferred from one reactant to

another?

A. electrons

B. water molecules

C. protons

D. OH ions

C. Protons are transferred from one reactant to another.

According to the kinetic-molecular theory, particles of matter

A. are in constant motion.

B. have different shapes.

C. have different colors.

D. are always fluid.

A. Particles of matter are in constant motion.

Acids react with

A. bases to produce salts and water.

B. salts to produce bases and water.

C. water to produce bases and salts.

D. neither bases, salts, nor water.

A. Bases to produce salts and water.

If doubling the concentration of a reactant doubles the rate of the reaction, the

concentration of the reactant appears in the rate law with a(n)

A. exponent of 1.

B. exponent of 2.

C. exponent of 4.

D. coefficient of 2.

The concentration of the reactant appears in the rate law with an exponent of 1.

Pure water contains

A. water molecules only.

B. hydronium ions only.

C. hydroxide ions only.

D. water molecules, hydronium ions, and hydroxide ions.

Water molecules, hydronium ions, and hydroxide ions.

Free-energy change depands on

A. change of entropy only

B.temperature only

C. change of enthalpy only

D. temperature and changes of entropy and enthalpy.

Depends on temperature and changes of entropy and enthalpy.

An equilibrium mixture of SO2, O2, and SO3 gases at 1500 K is determined to consist of

0.111 mol/L SO2 0.222 mol/L O2 and 0.333 mol/L SO3. The balanced equation for this reaction is

2SO2(g) + O2(g) <-> 2SO3(g). To solve for the equilibrium constant, what will the substitution of the

numerator look like?

A. (0.111)(0.222)(1500)

B. (0.111)^2(0.222)

C. (0.333)(1500)

D. (0.333)^2

D. (0.333)^2

The rate of reaction does not depend on the concentration of the reactant A when the

order of reactant A is

A. zero.

B. one.

C. two.

D. three

The rate of reaction does not depend on the concentration of reactant A when the order is zero.

What is the net ionic equation for the precipitation reaction between BaCl2 and Na2SO4

A. Ba2+(aq)+SO42-(aq) -> BaSO4(s)

B. Na+(aq)+Cl- (aq) -> NaCI(s)

C. Ba2+(aq)+2Cl-(aq)+2Na+(aq)+SO42-(aq)-> BaSO4(s) + 2Cl- (aq) +2Na+(aq)

D. BaCl2(aq)+ Na2SO4(aq) -+ BaSO4(s) + 2NaCl(aq)

Ba2+(aq)+SO42-(aq) -> BaSO4(s).

The [OH-] of an aqueous solution is 1.0 x 10^-5 M. What is the [H3O+]

A. 1.0×10^-9M

B. 1.0×10^-7M

C. 5.00

D. 9.00

1.0 x 10^-5 M leads to [H3O+] of 1.0×10^-9M.

The rate for a reaction between reactants X, Y, and Z is directly proportional to [X] and to

[Y] and proportional to the square of [Z]. What is the rate law for this reaction?

A. R= k[X][Y][Z]^2

B. R = k[X][Y][2Z]

C. R = k[X][Y][2Z]^2

D. R = k([X][Y])/([Z]^2)

R= k[X][Y][Z]^2.

An example of increasing entropy is the

A. formation of crystals from a solution.

B. formation of 1 mol of gas from 1 mol of one reactant gas and 1 mol of another reactant

gas.

C. dissolution of crystals into a solution.

D. None of the above

C. dissolution of crystals into a solution.

For an exothermic reaction, the products

Are at the same energy level as the reactants

Have no energy

Are at a lower energy level than the reactants

Are at a higher energy level than the reactants

Are at a lower energy level than the reactants

The volume of a gas is 0.40 L when the pressure is 1 atm. A student is told to calculate the new pressure at the same temperature when the volume of gas is changed to 2L. Which process below would correctly solve the problem?

Prior to solving, the unknown temperature will have to be converted to Kelvin.

Temperature is assumed constant and will be removed from the formula PV=nRT to solve for pressure

Temperature is assumed constant and will be removed from the formula P1V1/T1 = P2V2/T2 to solve for pressure.

Any gas law formula can be used as long as temperature is assumed constant and removed from it.

Temperature is assumed constant and will be removed from the formula P1V1/T1 = P2V2/T2 to solve for pressure.

A student is solving for the molarity of an aqueous solution. The mass of the solute is

1.00g and the volume of the total solution is 100. mL. Which of the steps below must be

completed before dividing to solve for molarity?

A. Convert grams of solute to kilograms.

B. Convert mL of solution to grams.

C. Use the molar mass of the solvent to convert mass to moles.

D. Use the molar mass of the solute to convert mass to moles.

D. Use the molar mass of the solute to convert mass to moles.

The rate-determining step of a reaction is always the

A. first step

B. last step

C. fastest step.

D. slowest step.

D

Which does not affect the rate at which a solid solute dissolves?

A. the vapor pressure of the solvent

B. the temperature of the solvent

C. the surface area of the solid

D. the speed at which the solution is stirred

A

Which gas is most likely to deviate from ideal gas behavior?

A. Ne

B. CO2

C. NH3

D. H2

C

Consider the reaction represented by the equation 2NO(g)+O2(g) <-> 2NO2(g). If the

volume of the reaction chamber is decreased, then the

A. forward reaction will be favored.

B. reverse reaction will be favored.

C. initial pressure of NO2 is decreased.

D. initial pressure of O2 will remain constant.

A. forward reaction will be favored.

A very low value of K indicates that

A. equilibrium is reached slowly.

B. products are favored.

C. reactants are favored

D. equilibrium has been reached.

C. reactants are favored

The minimum energy that two colliding molecules need before a chemical transformation can take place is the

A. rate-determining energy.

B. activation energy.

C. reaction order energy.

D. activated complex energy.

B. activation energy.

Which of the following is the right side of the equation for dissolving Al(NO3)3?

A. Al+ + (NO3)3-

B. Al3+(aq) + 3NO3- (aq)

C. Al3+ + NO3 3-

D. Al3- (aq) + 3NO3+ (aq)

B. Al3+(aq) + 3NO3- (aq)

At equilibrium, the total amount of the product(s)

A. is always equal to the total amount of the reactants.

B. is always greater than the total amount of the reactants.

C. is always less than the total amount of the reactants.

D. may be equal to, greater than, or less than the total amount of the reactants.

D. may be equal to, greater than, or less than the total amount of the reactants.

Hydrogen gas is collected by water displacement at 25.0°C. The barometric pressure is

752.0 torr. Which math formula and information is needed to solve for the pressure of hydrogen

A. (PV = nRT) and a reference table of the vapor pressures of water

B. (P = P1 + P2 + ... ) and a reference table of the vapor pressures of water

C. (PV = nRT) and (TKelvin=TCelcius+273)

D. (PT = P1 + P2 + ... )and(TKelvin=TCelcius+273)

A. (PV = nRT) and a reference table of the vapor pressures of water

At 300 K, a reaction has a delta H of -50.0 kJ and a delta S of -1.00 kJ/K. Which statement is

the output of the results of the calculation based on the measurements provided.

A. The answer will be negative and the reaction is not thermodynamically favored.

B. The answer will be negative and the reaction is thermodynamically favored.

C. The answer will be positive and the reaction is not thermodynamically favored.

D. The answer will be positive and the reaction is thermodynamically favored.

C. The answer will be positive and the reaction is not thermodynamically favored.