Ap Chem quick quizzes

The mass spectrum of the element titanium, Ti, is most likely represented by which of the following? A B C D

A

Lewis diagrams of molecules of three different hydrocarbons are shown below. Which of the following claims about the molecules is best supported by the diagrams?

The strongest carbon-to-carbon bond occurs in molecule 3.

How many of the following molecules have two pi (π) bonds: HCN, C₂H₂, CO₂, OCl₂? 0 1 2 3

3

Which of the following diagrams best illustrates how a displacement in an ionic crystal results in cleavage and brittleness? (The image on the left is before displacement, and the image on the right is after displacement)

A

Determine ΔH for the reaction of methane with oxygen. A. -3420 kJ B. -880 kJ C. -430 kJ D. -370 kJ

A. -3420 kJ

Which of the following correctly lists the given amounts of compounds in order of increasing mass? A. 0.5 mol Fe(NO₃)₂ < 0.5 mol Cu(NO₃)₂ < 2.0 mol Fe(NO₃)₂ B. 0.5 mol Fe(NO₃)₂ < 2.0 mol Fe(NO₃)₂ < 0.5 mol Cu(NO₃)₂ C. 0.5 mol Cu(NO₃)₂ < 0.5 mol Fe(NO₃)₂ < 2.0 mol Fe(NO₃)₂ D. 2.0 mol Fe(NO₃)₂ < 0.5 mol Fe(NO₃)₂ < 0.5 mol Cu(NO₃)₂

A. 0.5 mol Fe(NO₃)₂ < 0.5 mol Cu(NO₃)₂ < 2.0 mol Fe(NO₃)₂

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? 1/1 A. The attractive and repulsive forces are balanced, so the atoms will maintain an average internuclear distance x. B. There is a net repulsive force pushing the atoms apart, so the atoms will move further apart. C. There is a net attractive force pulling the atoms together, so the atoms will move closer together. D. It cannot be determined whether the forces between atoms are balanced, attractive, or repulsive, because the diagram shows only the potential energy.

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

Which of the following best explains the difference in the melting points of MgO (2852 °C) and NaF (1819 °C)? A. There are greater Coulombic attractions in MgO due to the greater charges of the ions. B. Na is above Mg on the activity series of metals. C. F is more electronegative than O. D. Na is an alkali metal, and Mg is an alkaline earth metal. Alkali metals are more reactive than alkaline earth metals.

A. There are greater Coulombic attractions in MgO due to the greater charges of the ions.

Which of the following represents an electron configuration that corresponds to the valence electrons of an element for which there is an especially large jump between the first and second ionization energies? (Note: n represents a principal quantum number equal to or greater than 2.) A. ns¹ B. ns² C. ns²np¹ D. ns²np²

A. ns¹

In the following diagrams, elements are represented by X and Z, which form molecular compounds with one another. Which diagram represents a molecule that has a bent molecular geometry?

B

In the following diagrams, elements are represented by X and Z, which form molecular compounds with one another. Which diagram represents a molecule that has a bent molecular geometry? A B C D

B

Which of the following Lewis diagrams best represents the bonding in the N₂O molecule, considering formal charges?

B

Which of the following expressions could be used to find the mass of 4.52 x 10²¹ atoms of iron? A. (4.52x10^(21)atoms)/(55.85g/mol)(6.022*10^(23)atoms/mol) B. (4.52x10^(21)atoms)/(6.022x10^(23)atom/mol)(55.85g/mol ) C. (6.022x10^(23)atoms/mol)/(55.85g/mol)(4.52x10^(21)atoms) D.(6.022x10^(23)atoms/mol)/(4.52x10^(21)atoms)(55.85g/mol )

B. (4.52x10^(21)atoms)/(6.022x10^(23)atom/mol)(55.85g/mol )

Which of the following electron configurations shows the ground state of an ion of a halogen? 1/1 A. 1s²2s²2p⁶3s²3p⁵ B. 1s²2s²2p⁶3s²3p⁶ C. 1s²2s²2p⁶3s²3p⁶3d⁵ D. 1s²2s²2p⁶2d¹⁰3s²3p⁶

B. 1s²2s²2p⁶3s²3p⁶

What is the electron configuration of Zn²⁺? A. 1s²2s²2p⁶3s²3p⁶3d⁸ B. 1s²2s²2p⁶3s²3p⁶3d¹⁰ C. 1s²2s²2p⁶3s²3p⁶3d⁸4s² D. 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²

B. 1s²2s²2p⁶3s²3p⁶3d¹⁰

The complete photoelectric spectrum of an element is given below. Which of the following electron configurations is consistent with the spectrum? A. 1s²2s²2p⁶3s¹ B. 1s²2s²2p⁶3s²3p⁶4s¹ C. 1s²2s²2p⁶3s²3p⁶4s² D. 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰4f¹⁴5s²5p⁶5d¹⁰5f¹⁴6s¹

B. 1s²2s²2p⁶3s²3p⁶4s¹

A student used a standard ruler to measure the dimensions of a cylinder. These measurements are: height of 11.23 cm, and diameter of 4.88 cm. When student calculates the volume of the cylinder, how many significant figures should be in the value? A. 2 B. 3 C. 4 D. 5

B. 3

The elements C and Se have the same electronegativity value, 2.55. Which of the following claims about the compound that forms from C and Se is most likely to be true? A. The carbon-to-selenium bond is unstable. B. The carbon-to-selenium bond is nonpolar covalent. C. The compound has the empirical formula CSe . D. A molecule of the compound will have a partial negative charge on the carbon atom.

B. The carbon-to-selenium bond is nonpolar covalent.

The melting point order of the following compounds is as follows: LiF > NaCl > KBr > CsI. Which of the following correctly explains this trend? A. The increasing molar mass requires more energy to melt the substances. B. The greater radii of the larger ions results in smaller lattice energies, leading to lower melting points. C. Reactivity increases as you increase the atomic number in the alkali metals. The more reactive, the easier it is to lose electrons, hence a lower melting point. D. The melting point is directly proportional to the electronegativity value for the halogen ions in the compound; there is more attraction for the electrons in the chemical bonds.

B. The greater radii of the larger ions results in smaller lattice energies, leading to lower melting points.

Which of the following best describes how the mass percentage composition of CH₂O, C₆H₁₂O₆, and HC₂H₃O₂ compare to one another? A. C₆H₁₂O₆ would have the greatest percentage of each element because it has the greatest mass. B. The mass percentage composition for each compound would be the same, because they have the same empirical formula. C. HC₂H₃O₂ has higher percentages of carbon and oxygen because the first hydrogen isn't included in the mass percentage calculation. D. The mass percentage composition for each compound would be the same, because they all have the same molecular formula.

B. The mass percentage composition for each compound would be the same, because they have the same empirical formula.

A student obtains a small sample of a pure solid compound. What set of information contains all the necessary information to determine the number of molecules in the sample? A. Avogadro's number, density of the compound, and mass of the sample B. Avogadro's number, mass of the sample, and volume of the sample C. Avogadro's number, molar mass of the compound, mass of the sample D. Molar mass of the compound, density of the compound, volume of the sample

C. Avogadro's number, molar mass of the compound, mass of the sample

Which of the following species has a central atom with less than an octet of electrons A. H₂O B. NH₃ C. BH₃ D. CH₄ E. SiH₄

C. BH₃

Which of the following correctly ranks the bonds in order of increasing ionic character? A. N-O < Ca-O < C-F < Br-Br < K-F B. K-F < Br-Br < C-F < Ca-O < N-O C. Br-Br < N-O < C-F < Ca-O < K-F D. Br-Br < C-F < N-O < K-F < Ca-O

C. Br-Br < N-O < C-F < Ca-O < K-F

Which of the following observations would provide evidence that the spectrum below is consistent with the atomic model of the element? A. A neutral atom of the element contains exactly 10 electrons. B. This element is highly reactive with nonmetals. C. In compounds, the element tends to form ions with a charge of -1. D. In compounds, the element tends to form ions with a charge of +5.

C. In compounds, the element tends to form ions with a charge of -1.

Two pure elements react to form a compound. One element is an alkali metal, X , and the other element is a halogen, Z . Which of the following is the most valid scientific claim that can be made about the compound? A. It has the formula XZ₂ . B. It does not dissolve in water. C. It contains ionic bonds. D. It contains covalent bonds.

C. It contains ionic bonds.

Which of the following elements has the mass spectrum shown? A. Ca B. Ra C. Sr D. Rb

C. Sr

Which of the following best helps explain why the electronegativity of Br is less than that of Cl? A. The mass of the Br atom is greater than the mass of the Cl atom B. The Br nucleus contains more protons than the Cl nucleus contains. C. When Br and Cl form bonds with other atoms, the Br bonding electrons are more shielded from the positive Br nucleus than the Cl bonding electrons are shielded from the positive Cl nucleus. D. Because Br is larger than Cl, the repulsions among electrons in the valence shell of Br are less than the repulsions among electrons in the valence shell of Cl.

C. When Br and Cl form bonds with other atoms, the Br bonding electrons are more shielded from the positive Br nucleus than the Cl bonding electrons are shielded from the positive Cl nucleus.

The lattice energy of four compounds of iron (FeCl₂, FeCl₃, FeO, and Fe₂O₃)are shown below. Which shows the correct relationship between lattice energies and the compounds?

D

Which of the following complete Lewis diagrams represents a molecule containing a bond angle that is closest to 120° ?

D

Which of the following is the ground-state electron configuration of the P³⁻ ion? A. 1s²2s²2p⁶ B. 1s²2s²2p⁶3s² C. 1s²2s²2p⁶3s²3p³ D. 1s²2s²2p⁶3s²3p⁶

D. 1s²2s²2p⁶3s²3p⁶

Which bond would be the most polar? A. P-Br B. As-Br C. Sb-Br D. Bi-Br

D. Bi-Br

Given a 1 g sample of each of MgO, CaO, CaS , which list correctly ranks them in order of increasing number of moles? A. MgO < CaO < CaS B. CaO < CaS < MgO C. CaS < MgO < CaO D. CaS < CaO < MgO

D. CaS < CaO < MgO

Which of the following correctly ranks the following species from smallest to largest ionic radius? A. Cl⁻, S²⁻, K⁺, Ca²⁺ B. K⁺, Ca²⁺, Cl⁻, S²⁻ C. S²⁻, Cl⁻, K⁺, Ca²⁺ D. Ca²⁺, K⁺, Cl⁻, S²⁻

D. Ca²⁺, K⁺, Cl⁻, S²⁻

A compound is composed of 39.9% C, 6.7% H, and 53.4% O, and has a molar mass of 120.1 g/mol. What is the molecular formula for this compound? A. CH₂O B. C₂H₂O₂ C. C₃H₄O₅ D. C₄H₈O₄

D. C₄H₈O₄

The diagram above is a molecular model of a gaseous diatomic element that is just above its boiling point. Intermolecular forces between the gas molecules will cause them to condense into the liquid phase if the temperature is lowered. Which of the following best describes how the model is limited in its depiction of the phenomenon? A. It does not show how hydrogen bonds are constantly forming, breaking, and reforming, which results in a net force of attraction between the molecules. B. It does not show how the interactions between ions and the induced molecular dipoles result in a net force of attraction between the molecules. C. It does not show how the interacting permanent dipoles of the molecules result in a net force of attraction between the molecules. D. It does not show how the temporary fluctuating dipoles of the molecular electron clouds result in a net force of attraction between the molecules.

D. It does not show how the temporary fluctuating dipoles of the molecular electron clouds result in a net force of attraction between the molecules.

Which of the following scientific claims about the bond in the molecular compound HF is most likely to be true? A. There is a partial negative charge on the H atom. B. Electrons are shared equally between the H and F atoms. C. The bond is extremely weak. D. The bond is highly polar.

D. The bond is highly polar.

Which of the following best helps to explain why the electron affinity of S has a greater magnitude than that of P? A. S has a greater electronegativity than P. B. S has a lower ionization energy than P. C. An added electron would go into a new shell in S but not in P. D. There is a greater attraction between an added electron and the nucleus in S than in P.

D. There is a greater attraction between an added electron and the nucleus in S than in P.

Of the following compounds, which is the most ionic? A. SiCl₄ B. BrCl C. PCl₃ D. Cl₂O E. CaCl₂

E. CaCl₂

Which of the following species has two lone pairs of electrons?

H₂O

The diagram above shows two resonance structures for a molecule of C₆H₆. The phenomenon shown in the diagram best supports which of the following claims about the bonding in C₆H₆?

In the C₆H₆ molecule, all the bonds between the carbon atoms have the same length.

Which of the following statements, if true, would support the claim that the NO₃⁻ ion, represented above, has three resonance structures?

The NO₃⁻ ion is not a polar species.

Lewis diagrams of molecules of three different hydrocarbons are shown below. Which of the following claims about the molecules is best supported by the diagrams? All the atoms in molecule 1 lie in one plane. All the molecules have the same empirical formula. The C-C-C bond angle in molecule 2 is close to 180° . The strongest carbon-to-carbon bond occurs in molecule 3.

The strongest carbon-to-carbon bond occurs in molecule 3.

In a molecule which the central atom exhibits sp³ hybrid orbitals, the electron pairs are directed toward the corners of a tetrahedron trigonal pyramid trigonal bipyramid square-based pyramid

tetrahedron