Chemistry Exam #2 (Practice Exams)

What is the charge of the polyatomic ion in the compound Fe(NO3)3?

-1

How many moles of S are present in 30.0g sample of H2S?

0.880 mol S

What is the approximate C—O bond order in the carbonate ion, CO3^2-?

1.33

The H-C-C angle in C2H4 is _____

120*

The Lewis electron dot structure below is missing multiple bonds and lone pair electrons. Fill-in the missing components; the resulting structure will have ___ lone pair and ___ double bonds. H H H H | | | | H-C-C-N-C-N-H

2, 2

How many sulfur atoms are in 25.6 g of Al2(S2O3)3?

2.37x10^23 S atoms

The Lewis structure of AsCl3 has ____ single bonds, ____ double bonds and ____ lone pairs.

3, 0, 10

How many grams of aluminum are in 25.6 g of Al2(S2O3)3?

3.54g Al

What is the mass of aluminum that can be produced by the reaction of 60.0 g of aluminum oxide with enough amount of carbon according to the following chemical reaction? Al2O3 + 3C --> 2Al + 3CO

31.8g Al

Assuming sufficient ammonia, NH3, what mass of hydrogen fluoride, HF, could be produced from 64.9 g of fluorine, F2, according to the reaction below. 2NH3(g) + 5F2(g) → N2F4(g) + 6HF(g)

41.0g

Using the smallest, whole number coefficients, what is the coefficient for KOH when the following equation is balanced? __Cr2O3 + __KOH + __O2 → __K2CrO4 + __H2O

8

What set of species is arranged in order of increasing H—N—H bond angle? smallest → largest A. NH2- < NH3 < NH4+ B. NH4+ < NH3 < NH2- C. NH3 < NH2- < NH4+ D. NH3 < NH4+ < NH2- E. NH4+ < NH2- < NH3

A. NH2- < NH3 < NH4+

Which substance has both covalent and ionic bonds? A. NH4Br(s) B. CH2Cl2(l) C. KI(s) D. SiF4(g)

A. NH4Br(s)

Consider three compounds, NaCl, Cl2 and HCl. Which statement is true? A. NaCl is a solid at room temperature, Cl2 and HCl are gases. B. Cl2 is a solid at room temperature, NaCl and HCl are gases. C. HCl is a solid at room temperature, NaCl and HCl are gases. D. NaCl and HCl are solids at room temperature, Cl2 is a gas. E. Cl2 and HCl are solids at room temperature, NaCl is a gas.

A. NaCl is a solid at room temperature, Cl2 and HCl are gases.

Which of the following will have a Lewis structure in which central atom must exceed the octet rule? A. SF4 B. CS2 C. CF4 D. NO2+ E. ClF3 F. NO2

A. SF4 and E. ClF3

According to VSEPR Model, which one of the following molecules has a tetrahedral molecular geometry? A. NH3 B. CCl4 C. CO2 D. SO3 E. HCN F. SF4

B. CCl4

Which molecule or compound below contains the most non polar covalent bond? A. Li2CO3 B. F2 C. NaCl D. SCl6 E. PF3

B. F2

According to VSEPR Model, which one of the following molecules would have the smallest bond angle? A. CO2 B. SO2 C. BeCl2 D. HCN

B. SO2

An atom has two hybrid orbitals arranged in a linear geometry. Which of the following statements is true? A. The atom has one p orbital available for pi bonding. B. The atom has two p orbitals available for pi bonding. C. The atom has no pi orbitals. D. The atom has an s orbital available for sigma bonding.

B. The atom has two p orbitals available for pi bonding.

Arrange the diatomic molecules nitrogen (N2), oxygen (O2) and bromine (Br2) in order of increasing bond strength based on your knowledge of the relative strengths of single, double and triple bonds. (Hint: draw out the molecules.)

Br2 < O2 < N2

For each set, which bond would you expect to be the MOST polar? Set I: C—H, C—C, C—N Set II: H—Cl, H—Br

C-N in Set I and H-Cl in Set II

Which of the following is a polar molecule? A. CS2 B. BCl3 C. NBr3 D. SiF4 E. PCl5 F. SF6

C. NBr3

Which of the following statements is correct? A. The boiling point of H2O is significantly higher than the boiling point of H2S due to greater dispersion forces. B. The boiling point of H2S is significantly higher than the boiling point of H2O due to greater dispersion forces. C. The boiling point of H2O is significantly higher than the boiling point of H2S due to the presence of H-bonding. D. The boiling point of H2S is significantly higher than the boiling point of H2O due to the presence of H-bonding.

C. The boiling point of H2O is significantly higher than the boiling point of H2S due to the presence of H-bonding.

Which of the following has the smallest bond angle? A. ammonia, NH3 B. methane, CH4 C. water, H2O D. All three have the same bond angle.

C. water, H2O

Which alcohol should be most soluble in a nonpolar solvent such as hexane, C6H14? CH3CH2CH2CH2CH2OH CH3CH2OH CH3CH2CH2OH CH3CH2CH2CH2OH

CH3CH2CH2CH2CH2OH

Which of the following compounds is capable of hydrogen bonding with itself? CH3CH3 H2CO HCN HCl CH3NH2

CH3NH2

Which of the following combinations will give an ionic compound with the highest melting point? -calcium and fluorine -potassium and fluorine -barium and fluorine -cesium and fluorine

Calcium and fluorine

7.53 × 1023molecules of an element has a mass of 88.64 g. What is the identity of this molecular element?

Cl2

A Lewis Structure of which of the following polyatomic ions has a central atom that can be drawn with an expanded octet? CO3^2- NH4+ NO2- NO3- ClO4-

ClO4-

Arrange the following polyatomic ions by increasing negative charge. ClO4^x PO4^x CO3^x

ClO4^- < CO3^2- < PO4<3-

Which of the following has the highest boiling point? A. N2 B. H2S C. NH3 D. H2O E. SO2

D. H2O

Which of the following solids would have the highest melting point? Which the lowest? A. NaI C. MgCl2 B. NaF C. MgCl2 D. MgO

D. MgO

Which of each of the following pairs has the highest boiling point? Pair I: HCl and HF Pair II: Cl2 and F2

HF and CL2

What would you predict for sulfur difluoride, SF2?

It is a polar molecular compound with polar S-F bonds.

The molecules in a sample of solid SO2 are attracted to each other by a combination of...

London forces and dipole-dipole interactions

What is the formula for the simple ionic compound formed by magnesium and iodine?

MgI2

Consider the polyatomic ions NO2+, NO2- and NO3-. Which has the largest bond order, which the smallest?

NO2+ has the highest bond order and NO3- has the lowest bond order.

Which of the following molecules or ion will exhibit delocalized bonding? NO2- NO2+ N3-

NO2- and N3-

Place the following elements in increasing order of electronegativity. Al Cl Na Si

Na <Al < Si < Cl

Which ionic compound in each pair has a smaller lattice energy? Pair I: LiF or NaF Pair II: KF or CaF2

NaF and KF

Which oxide contains ionic bonds? H2O NO2 SO2 SiO2

None as none are ionic compounds.

The electron pair geometry of XeF5+ molecule is_________ and the molecular shape is _______.

Octahedral, square pyramidal

Arrange the bonds by increasing polarity: S—S, S—Br, S—Cl.

S-S < S-Br < S-Cl

In each pair, indicate which would be expected to have the higher boiling point? SF4 or SF6 NH3 or PH3

SF4 and NH3

Predict the molecular shape and polarity of the SO2 molecule.

bent, polar

What are all of the intermolecular forces that are responsible for the existence of ice?

dipole-dipole and london forces

VSEPR diagram- Electron domants: 2 Electron geometry:? Molecular shape: ?

linear, linear

VSEPR diagram- When it has 6 electron domains the geometric electron is ________ and the molecular shape can be either _____, _____ or _____.

octahedral; octahedral, square pyramidal, square planar.

According to Molecular Orbital Theory, two separate 1s orbitals interact to form what molecular orbital(s)?

sigma and sigma*

What hybridization best describes the central atom if it has the T shaped molecular geometry.

sp3d

VSEPR diagram- When it has 4 electron domains the geometric electron is ________ and the molecular shape can be either _____, _____ or _____.

tetrahedral; tetrahedral, trigonal planar or bent.

VSEPR diagram- When it has 5 electron domains the geometric electron is ________ and the molecular shape can be either _____, _____, _____ or _____.

trigonal bipyramidal; trigonal bipyramidal, see-saw, T-shaped or linear.

VSEPR diagram- When it has 3 electron domains the geometric electron is ________ and the molecular shape can be either _____ or _____.

trigonal planar; trigonal planar or bent