AP Chemistry Quiz 1

A kinetics experiment is set up to collect the gas that is generated when a sample of chalk, consisting primarily of solid CaCO₃, is added to a solution of ethanoic acid, CH₃COOH. The rate of reaction between CaCO₃ and CH₃COOH is determined by measuring the volume of gas generated at 22^oC and 1 atm as a function of time. Which of the following experimental conditions is most likely to increase the rate of gas production?

• Decreasing the volume of ethanoic acid solution used in the experiment

• Decreasing the concentration of the ethanoic acid solution used in the experiment

• Decreasing the temperature at which the experiment is performed

• Decreasing the particle size of the CaCO₃ by grinding it into a fine powder

A 100 g sample of a metal was heated to 100^oC and then quickly transferred to an insulated container holding 100 g of water at 22^oC . The temperature of the water rose to reach a final temperature of 35^oC . Which of the following can be concluded?

• The metal temperature changed more than the water temperature did; therefore the metal lost more thermal energy than the water gained.

• The metal temperature changed more than the water temperature did, but the metal lost the same amount of thermal energy as the water gained.

• The metal temperature changed more than the water temperature did; therefore the heat capacity of the metal must be greater than the heat capacity of the water.

• The final temperature is less than the average starting temperature of the metal and the water; therefore the total energy of the metal and water decreased.

Which of the following particulate diagrams best shows the formation of water vapor from hydrogen gas and oxygen gas in a rigid container at 125^oC

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A 50.0 mL sample of an acid, HA, of unknown molarity is titrated, and the of the resulting solution is measured with a meter and graphed as a function of the volume of 0.100 M NaOH added.

At point R in the titration, which of the following species has the highest concentration?

• HA

• A^-

• H₃O⁺

• OH^-

A 50.0 mL sample of an acid, HA, of unknown molarity is titrated, and the of the resulting solution is measured with a meter and graphed as a function of the volume of 0.100 M NaOH added.

Which of the following is the best particulate representation of the species (other than H₂O) that are present in significant concentrations in the solution at point U in the titration?

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A 50.0 mL sample of an acid, HA, of unknown molarity is titrated, and the of the resulting solution is measured with a meter and graphed as a function of the volume of 0.100 M NaOH added.

At which point on the titration curve is [A-] closest to twice that of [HA]?

• R

• S

• T

• U

A 50.0 mL sample of an acid, HA, of unknown molarity is titrated, and the of the resulting solution is measured with a meter and graphed as a function of the volume of 0.100 M NaOH added.

A student carries out the same titration but uses an indicator instead of a pH meter. If the indicator changes color slightly past the equivalence point, what will the student obtain for the calculated concentration of the acid?

• Slightly less than 0.0800 M

• Slightly more than 0.0800 M

• Slightly less than 0.125 M

• Slightly more than 0.125 M

The average kinetic energy of the gas molecules is

• greatest in container A

• greatest in container B

• greatest in container C

• the same in all three containers

The density of the gas, in g/L, is

• greatest in container A

• greatest in container B

• greatest in container C

• the same in all three containers

If the pressure of each gas is increased at constant temperature until condensation occurs, which gas will condense at the lowest pressure?

• Methane

• Ethane

• Butane

• All the gases will condense at the same pressure