AP Chem Midterm

If equal masses of the following compounds undergo complete combustion, which will yield the greatest mass of CO2?

A. Benzene (C6H6)

On the basis of the data provided above the gas in container three could be

A. CH4

On the basis of the information above, which of the following arranges the binary compounds in order of increasing bond polarity

A. CH4 < SiCl4 < SF4

Under the conditions given consider containers 2, and 4 only. The average speed of the gas particle is

A. Greatest in container 1

A 0.5 mole sample of HE and a 0.5 mol sample Of NE are placed separately in two 10.0 L rigid containers at 25°C each.

A. He(g) will escape faster because the He(g) atoms are moving at a higher average speed than the Ne(g) atoms.

A sample of a hard, solid binary compounds at room temperature did not conduct electricity as a pure solid but became highly conductive when dissolved in water. Which of the following types of interactions is most likely found between the particles in the substance

A. Ionic bonds

In the reaction represented above the number of MNO4- ions that react must be equal to which of the following

A. One-fifth the number of Fe2+ ions that are consumed

The potential energy of a system of two atoms as a function of their internuclear distance is shown in the diagram above. Which of the following is true regarding the forces between the atoms when their internuclear distance is X

A. The attractive and repulsive forces are balanced, so the atoms will maintain an average internuclear distance X

Which of the following diagrams best depicts an alloy of Ni and B

A. The diagram with 4 rows of 4 with dots and grey dots scattered in the middle.

Which of the following diagrams best illustrates how a displacement in an ionic crystal results in cleavage and brittleness

A. The diagram with alternating negative and positive circles and then the right side shifts down.

The distribution of speeds of H2 molecules at 273K and one ATM is shown in the diagram above which of the following best shows the speed distribution of HE atoms under the same conditions of temperature and pressure

A. The one where He has a higher fraction of particles at a slower speed

Which of the following diagrams best represents the AgNO3 solution before the reaction occurs?

A. The one with the water molecules facing away from Ag+ and facing at NO3- with three scattered water molecules.

Steel is an alloy consisting of FE with a small amount of C. Elemental CR can be added to steel to make the steel less likely to rust; CR atoms react with oxygen in the air to form a non-reactive layer of chromium oxide on the surface of steel, preventing the oxidation of underlying Fe atoms. A sample of steel chromium alloy contains 15% CR by mass. Which of the following diagrams best shows a particle level view of a surface section and an interior section of the alloy represented below at the left?

B.

The first five ionization energy's of a second. Element are listed in the table above. Which of the following correctly identifies the element and best explains the data in the table.

B. B, because it has three valence electrons

The table above shows the structural formula and molar mass is for three different compounds. Which of the following is a list of the compounds in order of increasing boiling points

B. Butane < acetone < 1-propanol

A 23.0 g sample of a compound contains 12.0 g of C, 3.0 g of H, and 8.0 g of O. Which of the following is the empirical formula of the compound.

B. C2H6O

The molecular formula and molar mass of the two straight chain hydrocarbons are listed in the table above. Based on the information in the table, which compound has the higher boiling point, and why is that compounds boiling point higher

B. C4H10, because it has more electrons, resulting in greater polarizability and stronger dispersion forces.

Based on the information in the table above, which liquid, CS2 or CCL4, has the higher equilibrium vapor pressure at 25°C And why

B. Cs2(l), because it has weaker London dispersion forces

A mixture containing equal numbers of moles of ethyl acetate and butyl acetate was separated using distillation. Based on the diagram shown above which of the following identifies the substance that would be initially present and higher concentration in the distillate and correctly explains why that occurs

B. Ethyl acetate, because it has a shorter carbon chain and weaker London dispersion forces.

What is the identity of the metal chloride

B. KCl

According to the information in the table above, a 1.00 g sample of which of the following contains the greatest mass of oxygen

B. MgO

Based on coulombs law and the information in the table above, which of the following cations is most likely to have the weakest interaction with an adjacent water molecule in an aqueous solution

B. Na2+

Which of the following could be the identity of a white crystalline solid that exhibits the following properties?

B. NaOH (s)

A sample containing Adams of C and F was analyzed using x-ray photoelectron spectroscope. The portion of the spectrum showing me one S peaks for atoms of the two elements as shown above. Which of the following correctly identifies the one S peak for the F atoms and provide an appropriate explanation.

B. Peak X, because F has a greater nuclear charge than C has

Which of the following Lewis electron dot diagram represents the molecule that contains the smallest bond angle

B. The One with N and F in it

Which of the following molecules is least soluble in water

B. The one with C and Cl

A 6.0 mol sample of C3H8 and a 20.0 mole sample of CL2 are placed in a previously evacuated vessel, where they react according to the equation above. After one of the reactants has been totally consumed, how many moles of HCl have been produced.

C. 20 mol

Under which of the following conditions of temperature and pressure will H2 gas be expected to behave most like an ideal gas

C. 500 K and 0.10 atm

A sample of a compound that contains only the elements C, H, and N is completely burnt in O2 to produce 44.0 g of C02, 45.0 g of H2O, and some NO2. a possible empirical formula of the compound is

C. C2H5N

The best explanation for the lower pressure and container 4 is that S02 molecules

C. Have stronger intermolecular attractions than the other three gases

Which of the following is the strongest type of interaction that occurs between the atoms within the circled areas of the two molecules represented above

C. Hydrogen bond

At room temperature I2 is a molecular solid. Which of the following provides a characteristic of I2 with a correct explanation

C. It is not a good conductor of electricity because it's valence electrons are localized

The lattice energy of a salt is related to the energy required to separate the ions. For which of the following pairs of ions is the energy that is required to separate the ions largest? ( assume that the distance between the ions in each pair is equal to the sum of the ionic radii)

C. Mg2+ (g) and O2- (g)

The volume of a sample of air in a cylinder with a movable piston is 2.0 L at a pressure P1 as shown in the diagram above. The volume is increased to 5.0 L as the temperature is held constant. The pressure of the air in the cylinder is now P2. What effect to the volume and pressure changes have on the average kinetic energy of the molecules in the sample?

C. The average kinetic energy stays the same

The table above shows the first ionization energy and the atomic radius of several elements which of the following best helps to explain the deviation of the first ionization energy of oxygen from the overall trend

C. There is repulsion between paired electrons in oxygens 2P orbitals

Based on the ionization energy's of element X given in the table above, which of the following is the most likely the empirical formula of an oxide of element X.

C. X2O3

For element X represented above, which of the following is the most likely explanation for the large difference between the second and third ionization energy's?

C. the electron removed during the third ionization is, on average, much closer to the nucleus than the first two electrons removed were

Thymine and adenine form a base pair in the DNA molecule. These two bases conform a connection between two strands of DNA via to hydrogen bonds. Which of the following diagrams shows the correct representation of the hydrogen bonding between thymine and adenine base pairs?

D.

When a student adds 30 mL of 1.0 0M HCl to a 0.56 g of powdered FE, a reaction occurs according to the equation above. When the reaction is complete at 273K and 1.0 ATM, which of the following is true

D. 0.22 L of H2 has been produced.

Which of the following correctly identifies which has the higher First ionization energy, CL or Ar, and supplies the best justification?

D. Ar, because of its higher effective nuclear charge

In which of the following liquids do the intermolecular forces include dipole dipole forces?

D. CH2F2(l)

The photo electron spectra of the 1S electrons of two isoelectronic species, CA2+ and AR, are shown above. Which of the following correctly identifies the species associated with peak X and provides a valid justification.

D. Ca2+ , because it's nucleus has two more protons in the nucleus of Ar has

Based on the information above and periodic trends, which of the following is the best hypothesis regarding the oxide formed by RB

D. Rb will form Rb2O, Rb2O2, RbO2

The mass spectrum of element ex is presented in the diagram above. Based on the spectrum, which of the following can be concluded about element X

D. The atomic mass of X is between 90 and 92

A vessel contains Ar(g) at a high pressure. Which of the following statements best helps to explain why the measured pressure is significantly greater than the pressure calculated using the ideal gas law.?

D. The combined volume of The Ar atoms is too large to be negligible compared with the total volume of the container.

Benzene, C6 H6, has the structure shown above considering the observation that benzene is only sparingly soluble in water, which of the following best describes the intermolecular forces of attraction between the water and benzene

D. There are dimple induced dipole and London dispersión interactions between water and benzene.

During the course of the experiment, which of the following happens to the NO3- ions

D. They remain dissolved in the filtrate solution.

The BF3 molecule is nonpolar, where as the NF3 molecule is polar. Which of the following statements accounts for the difference in polarity of the two molecules

D. Unlike BF3, NF3 has a no polar geometry due to an unshared pair of electrons on the N atom.

In a paper chromatography experiment, a sample of a pigment is separated into two compounds, X and Y, as shown in the figure above. The surface of the paper is moderately polar. What can be concluded about X and Y based on the experiment results

D. Y is more Polar than X