Chemistry Ch. 8 & 9.5

How many sigma bonds and how many pi bonds are in an ethyne molecule (C2H2)?

3 sigma bonds; 2 pi bonds

Why is the chemical composition of water (H2O) always the same?

All of the other answer choices

How do dispersion forces compare to dipole interactions?

Both involve an electrical attraction between molecules, but dispersion forces are much weaker and temporary.

What is the IUPAC name of the compound CaCO3?

Calcium carbonate

How is an electron dot formula used to represent a covalent bond?

Dots for shared electron pairs are shown between the symbols for the bonding atoms.

What is the IUPAC name of the compound PbCrO4?

Lead(II) chromate

What is the IUPAC name of the compound SnCr2O7?

Tin(II) dichromate

In structural formulas, polar covalent bonds are identified with symbols showing slightly positive charge (δ+) and slightly negative charge (δ−) next to the appropriate atoms. How are these symbols placed in the structural formula for BrCl?

δ− next to Cl, δ+ next to Br

Use VSEPR theory to predict the bond angles in a molecule of water, which is a covalently bonded molecule.

105˚

Use VSEPR theory to predict the bond angles in a molecule of ammonia (NH3), which is a covalently bonded molecule.

107˚

Use VSEPR theory to predict the bond angles in a molecule of methane (CH4), which is a covalently bonded molecule.

109.5˚

How is the molecule with the chemical formula NO different from the molecule with the chemical formula N2O?

A NO molecule contains 1 atom of nitrogen, while a N2O molecule contains 2 atoms of nitrogen.

How is the strength of a covalent bond related to its bond dissociation energy?

A large bond dissociation energy indicates a strong covalent bond.

What is the chemical formula for barium fluoride?

BaF2

Which of the following is an incorrect name, and why?

Calcium(II) oxide, because a Roman numeral is not used with a Group A metal

What is the chemical formula for iron(III) oxalate?

Fe2(C2O4)3

Which best describes the electron dot formula for phosphorus trihydride (PH3), which is a molecular compound that contains only single covalent bonds?

Four pairs of dots placed around the symbol P, with one symbol H placed next to each of three different pairs (8 dots total)

Which best describes the electron dot formula for dihydrogen sulfide (H2S), which is a molecular compound that contains only single covalent bonds?

Four pairs of dots placed around the symbol S, with one symbol H placed next to one pair of dots and another symbol H placed next to another pair of dots (8 dots total)

How does hydrogen bonding help explain the unique role of water in chemical systems?

Hydrogen bonding increases the intermolecular attractions among water molecules, allowing water to be a liquid over a wide range of temperatures.

What is the chemical formula for tetraiodide nonoxide?

I4O9

Which is NOT a general guideline for writing the name of a compound?

If the compound is binary, generally the name ends with the name of the nonmetal, with no additional prefix or suffix.

How do the strengths of intermolecular attractions compare to the strengths of ionic bonds and covalent bonds?

Intermolecular attractions are weaker than either ionic or covalent bonds.

How does a network solid differ from most other molecular compounds?

It consists of a very large number of atoms that are all bonded to each other.

How are atomic and molecular orbitals related?

Just as an atomic orbital belongs to a particular atom, a molecular orbital belongs to a molecule as a whole.

What shape would you expect a simple carbon-containing compound to have if the carbon atom has sp hybridization?

Linear

Which formula is incorrect, and for what reason?

Mg(NH4)2, because the formula includes two cations

Orbital hybridization provides information about which of the following?

Molecular bonding and molecular shape

Which is a molecular formula of a diatomic molecule found in Earth's atmosphere?

N2

What are the only elements that exist in nature as uncombined atoms, and what term is used to describe such elements?

Noble gases; monatomic

Which of the following best describes how the law of definite proportions is consistent with Dalton's postulates?

Since atoms of elements combine in fixed ratios to form a given compound, the ratio of their masses in the compound is also fixed.

What is the chemical formula for tin(II) hydroxide?

Sn(OH)2

The BF3 molecule is planar. The attachment of a fluoride ion to the boron atom in BF3, through a coordinate covalent bond, creates the BF4− ion. Predict the geometric shape of this ion.

Tetrahedral

What shape would you expect a simple carbon-containing compound to have if the carbon atom has sp3 hybridization?

Tetrahedral

What kinds of information does a structural formula reveal about a molecular compound?

The arrangement of atoms and bonds in the molecule

What information does a molecular structure give that is not given by the molecular formula?

The arrangements of the atoms and bonds of a molecule

The bond dissociation energy of H2 is 435 kJ/mol. The bond dissociation energy of a typical carbon-carbon single covalent bond is 347 kJ/mol. What can be concluded from this information?

The bond between hydrogen atoms in H2 is stronger than the typical carbon-carbon single covalent bond.

Why do some molecules contain polar bonds, but are not polar molecules? (Hint: Consider CCl4 as an example.)

The bond polarities cancel out because they are in opposite directions.

Two compounds that contain copper and chlorine have the following masses: Compound A: 32.10 g Cu and 17.90 g Cl Compound B: 23.64 g Cu and 26.37 g Cl Are the compounds the same? If not, what is the lowest whole-number mass ratio of copper that combines with a given mass of chlorine?

The compounds are not the same. The mass ratio of copper per gram of chlorine is 2:1.

What electron configurations do atoms usually achieve by sharing electrons to form covalent bonds?

The configurations of noble gases

How do electronegativity values determine the charge distribution in a polar covalent bond?

The more electronegative atom gains a slight negative charge; the less electronegative atom gains a slight positive charge.

What information does a molecular formula provide?

The number of atoms of each element in the molecule.

How is the representative unit of a molecular compound different from the representative unit of an ionic compound?

The representative unit for a molecular compound is a molecule, and the representative unit for an ionic compound is a formula unit.

How is a coordinate covalent bond different from other covalent bonds?

The shared electron pair comes from one of the bonding atoms.

Why are the properties of molecular compounds so diverse?

The strengths of intermolecular attractions vary widely.

Which best describes the electron dot formula for chlorine monofluoride (ClF), which is a molecular compound that contains only a single covalent bond?

Three pairs of dots placed around the symbol Cl, three pairs of dots placed around the symbol F, and one pair of dots placed between the two symbols (14 dots total)

How are resonance structures used?

To envision the bonding in molecules that cannot be adequately described by a single structural formula

What do scientists use VSEPR theory for?

To predict the three-dimensional shapes of molecules

What shape would you expect a simple carbon-containing compound to have if the carbon atom has sp2 hybridization?

Trigonal planar

Which of the following combinations will form a sigma bond?

Two atomic orbitals overlapping along the axis between two nuclei

When are two atoms likely to form a double bond between them?

When sharing two pairs of electrons allows each atom to attain a noble gas electron configuration

When will the octet rule fail to be obeyed?

When the total number of valence electrons in a molecule is an odd number

In structural formulas, polar covalent bonds are identified with symbols showing slightly positive charge (δ+) and slightly negative charge (δ−) next to the appropriate atoms. How are these symbols placed in the structural formula for HBr?

δ− next to Br, δ+ next H

In structural formulas, polar covalent bonds are identified with symbols showing slightly positive charge (δ+) and slightly negative charge (δ−) next to the appropriate atoms. How are these symbols placed in the structural formula for H2O?

δ− next to O, δ+ next to both H symbols

In structural formulas, polar covalent bonds are identified with symbols showing slightly positive charge (δ+) and slightly negative charge (δ−) next to the appropriate atoms. How are these symbols placed in the structural formula for HOOH?

δ− next to each O, δ+ next to each H