AP Chemistry Review Lesson

AP Chemistry Review Lesson

By Nicole Woltschlaeger

Multiple Choice

Which of the following sublevels ends in the transition metal block when n = 3?

• 3s

• 3p

• 3d

• 3f

Multiple Choice

Which of the following sublevels ends with a noble gas when n = 3?

• 3s

• 3p

• 3d

• 3f

Multiple Choice

Unpaired electrons in this block lead to colored solutions.

• 3s

• 3p

• 3d

• 3f

Multiple Choice

This is a nonexistent orbital.

• 3s

• 3p

• 3d

• 3f

Multiple Choice

A chemist carries out a reaction to form a gaseous chemical which could have either one of the formulas shown. Which of the following describes how the chemist might best find out which is the formula of the compound made?

• Infra-red absorption spectrometry to look at vibrations of the carbon to carbon bonds.

• Visible light absorption spectrometry to look at electron transitions.

• Mass spectrometry to examine the exact mass of the two compounds.

• Gas diffusion measurements to determine the speeds of the gas molecules.

Multiple Choice

The diagram shows the results, after 4 minutes, from placing spots of three different dyes on paper strips 1 cm from the bottom of the strip and placing the paper in a small amount of solvent at the base in an enclosed container. Which best explains the results?

• The red dye has the strongest interactions with paper and the solvent

• The yellow dye has the weakest interactions with the solvent but the strongest interactions with the paper.

• Dye X is a mixture of dye A and dye B in equivalent amounts.

• The purple dye has the strongest interactions with the paper, but the weakest with the solvent.

Multiple Choice

Ammonia is frequently produced by the Haber process in which nitrogen gas, N₂, and hydrogen gas, H₂, are combined to form ammonia gas, NH₃. If 2 moles of nitrogen gas and 3 moles of hydrogen gas are reacted, what is the maximum amount of ammonia gas that could be produced?

• 2 mol

• 3 mol

• 4 mol

• 5 mol

Multiple Choice

If a 22.4 L volume of a sample of gas has a density of 0.900 g/L at 1.00 atm and 0.00 degrees Celsius, what could it be?

• Ne

• CO

• CO₂

• Kr

Start with 22.4 L and use 0.900 g/L as a conversion factor.

​

Answer is ~20 grams. A 22.4 Liter container of gas has 1 mole of gas, so the molar mass is 20 g/mol.

​

This matches Neon's molar mass.​

Multiple Choice

Which of the following represent a conjugate acid-base pair?

• HNO₃; H₂SO₄

• H₂O₂; H₃O⁺

• HCO₃^-;H₂CO₃

• H₂SO₄; SO₄^2-

Multiple Choice

Technetium-99m is a metastable nuclear isomer of technetium-99, symbolized as ^99mT_c. A hospital buys a sample of ^99mT_c, a radioactive isotope used to perform kidney scans of patients. The half-life of ^99mT_c is 6.0 hours. A technician needs to determine the rate constant for ^99mT_c to ensure the patient will receive enough of the isotope to produce a good scan. Which is the correct expression for calculating the rate constant for ^99mT_c in units of min^-1? ln2 = 0.693.

• 6.0 x 60

• 6.0/60

• 0.693 x (6.0 x 60)

• 0.693 /(60 x 60)

​Rate Laws

Subject | Subject

Some text here about the topic of discussion

​Radioactive decay is

first order.​

​

For a 1st order reaction,

t_1/2 = 0.693/k​

​

k has units of seconds, so have to convert from minutes.​

Multiple Choice

The half-life of a reaction with this order does not depend on reactant concentration.

• zero-order

• first-order

• second-order

• third-order

Multiple Choice

A graph of concentration vs. time is linear for a reaction with this order.

• zero-order

• first-order

• second-order

• third-order

Multiple Choice

What is the overall order of the reaction with the rate equation;

Rate = k[A][B]

• zero-order

• first-order

• second-order

• third-order

Multiple Choice

For the reaction A -> B, which energy change will determine the rate of reaction when the temperature of the reaction is increased?

• 1

• 2

• 3

• 4

Multiple Choice

If a catalyst is added, the expected change on the diagram will be to

• increase energy (1)

• decreases energy (2)

• increase energy (3)

• decrease energy (4)

Multiple Choice

The graph shows the distribution of speeds of gas particles for four different noble gases. The plots are different for the different gases because

• the gases are at different temperatures

• speeds are directly proportional to square root of mass

• speeds are inversely proportional to square root of mass

• the kinetic energies of the gases are different

A kind of average velocity -- some molecules move slower and some move faster.

As T increases, the rms increases so the ​curve becomes broader.

​

​Some text here about the topic of discussion.

​root mean squared velocity

Multiple Choice

If the curves represented one gas at four different temperatures, which curve would represent the highest temperature?

• A

• B

• C

• D

Multiple Choice

Which substance would exhibit the highest electrical conductivity when dissolved in water at room temperature?

• HNO₃

• N₂

• NH₂OH

• NO

Multiple Choice

Which substance contains only sigma bonds?

• HNO₃

• N₂

• NH₂OH

• NO

Multiple Choice

Which substance contains the bond with the highest energy?

• HNO₃

• N₂

• NH₂OH

• NO

Multiple Choice

Which substance contains an unpaired electron?

• HNO₃

• N₂

• NH₂OH

• NO

Multiple Choice

Which of the following can only be reduced?

• Fe²⁺

• MnO₄^-

• Cl^-

• Al

Multiple Choice

A weighed piece of Mg ribbon is added to a dried crucible, which is reweighed and heated in air to form the compound MgO. The crucible is cooled and reweighed to find the mass of MgO. Which error could lead to a mass percentage of Mg that is too low?

• The crucible contains a small amount of H₂O when it is reweighed with the Mg.

• The crucible is still warm when it is weighed with the product.

• The Mg ribbon has an oxide coating.

• The MgO formed absorbs moisture before it is weighed.

Multiple Choice

A can of compressed gas is at room temperature at normal atmospheric pressure. When the gas is released from the can as a spray, the nozzle of the can becomes cold. Which statement below best explains this event?

• An endothermic chemical reaction occurred between the air and the gas molecules.

• As the gas expanded coming out of the can, it did work on the opposing air pressure and lost kinetic energy.

• As the gas sprayed out, a vacuum was created inside the can.

• Pressure and temperature of a gas are directly related.

​As the gas in the can does work to push the opposing air molecules out of the way, it slows down the gas-can-molecules.

​

As the velocity of a particle decreases, so does its kinetic energy.

​

​Kinetic energy of gas IS PROPORTIONAL to temperature:

​

KE_avg = (3/2) RT​

Multiple Choice

The reaction 2SO₂(g) + O₂(g) $$\leftrightarrow$$  2SO₃(g) has an equilibrium constant of K₁.

What is K for the reaction SO₃(g) $$\leftrightarrow$$  SO₂(g) + ¹/₂O₂(g) in terms of K₁?

• 1/2 K₁

• 1/K₁

• (1/K₁)^1/2

• K₁^1/2

​Rules for manipulating k:

• If you reverse the equation, invert the equilibrium constant.

  • K_reverse = 1/K​_forward

• If you multiply the coefficients in the equation by a factor, raise the equilibrium constant to the same factor.

  • n = co​efficient, K' = Kⁿ

• If you add two or more individual chemical equations to obtain an ov​erall equation, multiply the corresponding equilibrium constants by each other to obtain the overall equilibrium constant.

  • K_overall = K₁ x K₂​

16.3 in your textbook

Multiple Choice

Melting of this solid requires the breaking of covalent bonds.

• Sand, SiO₂

• Ice, H₂O

• Wax, C₂₅H₅₂

• Salt, NaCl

Multiple Choice

Cylinders of Cu, Fe and Al with the same mass and temperature were heated on a hot plate as shown below. [Specific heats (J/g^oC): Al 0.90, Cu 0.39, Fe 0.45]

What is the result after two minutes?

• The three cylinders would have the same temperature.

• The Cu cylinder would have the highest temperature.

• The Fe cylinder would have the highest temperature.

• The Al cylinder would have the highest temperature.

Quantifying Heat

heat, q = m x C_s x ΔT

q_system = -q_surroundings

​

The heat, q, transferred from the hot plate to each metal cylinder is the same in each case. The masses are also all the same.

​

So if a metal has a small C_s, specific heat capacity, then it will experience a higher temperature change.​

7.4 in your textbook.​

Multiple Choice

The rate-determining step in a reaction mechanism is always the

• first step

• slowest step

• step with the fewest collisions

• step with the lowest activitation energy

Multiple Choice

A reaction will always be thermodynamically favored if

• $$\Delta H\degree\ is\ negative$$  

• $$\Delta G\degree\ is\ positive$$  

• $$\Delta S\degree\ is\ negative$$  

• E^o is positive