AP Chem Unit 1, 2 Test
Which of the following correctly ranks the substances listed above in order of increasing ionic character in their bonding?
(A) Cl2, PCl3, CaCl2
If a pure sample of an oxide of sulfur contains 40% sulfur and 60% oxygen by mass, then the empirical formula of the oxide is
(A) SO3
Which of the following statements, if true, would support the claim that NO3- ion, represented above, has three resonance structures?
(A) The NO3- ion is not a polar species
How many carbon atoms are contained in 2.8 g of C2H4
(A) 1.2 x 10^23
Which of the following diagrams best illustrates how a displacement in an ionic crystal results in cleavage and brittleness?
(A) Before displacement: equal size + and - ions. After displacement: Half of the diagram is shifted down
The potential energy as a function of intermolecular distance for three diatomic molecules, X2, Y2, Z2, is shown in the graph above. Based on the data in the graph, which of the following correctly identifies the diatomic molecules, X2, Y2, and Z2?
(A) X2:H2, Y2:N2, Z2:O2
Based on the ionization energies of element X given in the table above, which of the following is most likely the formula of the compound formed between element X and SO4^2-?
(A) XSO4
H-C=-C-H (Triple Bond) What is the hybridization of the carbon atoms in a molecule of ethyne, represented apove?
(A) sp
Based on periodic trends and the data in the table above, which of the following are the most probable values of the atomic radius and the first ionization energy for potassium, respectively?
(B) 242 pm, 419 kJ/mol
Which of the following lewis diagram best represents the bonding in the N2O molecule, considering formal charges?
(B) :N=-N-Ö: (two more dots under the O)
The first five ionization energies of a second-period 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
Copper atoms and zinc atoms have the same atomic radius, 135 picometers. Based on this information, which of the following diagrams best represents an alloy containing only copper and zinc atoms?
(B) Diagram with equal size grey and white circles
Which of the following best helps to account for the fact that the F- ion is smaller than the O2- ion?
(B) F- has a larger nuclear charge than O2- has
Which of the following Lewis electron-dot diagram represents the molecule that contains the smallest bond angle?
(B) NF3
After completing an experiment to determine gravimetrically the percentage of water in a hydrate, a student reported a value of 38%. The correct value for the percentage of water in the hydrate is 51%. Which of the following is the most likely explanation for this difference?
(B) The dehydrated sample absorbed moisture after heating
The mass spectrum of an average sample of a pure element is shown in the figure above. Which of the following is the identity of the element?
(B) Zr
The structural formula of the glycinium cation is shown above. Arrows indicate the pKa values for the labile protons in the molecule. What is the approximate H-O-C bond angle in the glycinium cation?
(C) 105º
A lewis diagram for the molecule C2H4 is shown above. In the actual C2H4 molecule, the H-C-H bond angles are closest to
(C) 120º
In 1.00 mol of potassium zirconium sulfate trhydrate, K4Zr(SO4)4 x 3 H20 there are
(C) 4 x 6.02 x 10^23 potassium atoms
1s^2 2s^2 2p^6 3s^2 3p^6 Which of the following species has the electron configuration shown above?
(C) K+
A compound contains 1.10 mol of K, 0.55 mol of Te, and 1.65 mol of O. What is the simplest formula of this compound?
(C) K2TeO3
Based on the ionization energies of element X given in the table above, which of the following is most likely the empirical formula of an oxide of element X?
(C) X2O3
The decrease in the second ionization energy of alkali metals going down the group, as shown in the table above, can be best attributed to a decrease in the coulombic force of attraction due to
(C) an increase in the average distance of the outermost electron from the nucleus
Which of the following ground-state electron represents the atom that has the lowest first-ionization energy?
(D) 1s^2 2s^2 2p^6 3s^1
In the reaction represented above, what is the hybridization of the C atoms before and after the reaction occurs?
(D) Before: sp2 After: sp3
Directions: Each set of lettered choices below refers to the numbered statements immediately following it. Select the one lettered choice that best fits each statement. A choice may be used once, more than once, or not at all in each set. The molecule with only one double bond
(D) C2H4
The photoelectron spectra f 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 its nucleus has two more protons than the nucleus of Ar has
RbCl has a high boiling point. Which of the following compounds is also likely to have a high boiling point, and why?
(D) CsCl, because its elements have very different electronegativities and it is an ionic compound
The mass spectrum of element X 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
The table above shows the melting points of MgO(s) and NaF(s). Which of the following best helps explain why the melting point of MgO(s) is much higher than NaF(s)?
(D) The charges of Mg2+ and O2- ions are greater than those of Na+ and F- ions
1s^2 2s^2 2p^6 3s^2 3p^3 Atoms of an element, X, have the electronic configuration shown above. The compound most likely formed with magnesium, Mg, is
(E) Mg3X2
Directions: Each set of lettered choices below refers to the numbered statements immediately following it. Select the one lettered choice that best fits each statement. A choice may be used once, more than once, or not at all in each set. The molecule that has trigonal pyramidal geometry
(E) PH3
