Chapter 7, 8, 9 - SmartBook

percent yield

(amount of product obtained/amount of product possible) x 100

the steps required to balance a simple redox reaction using the half-reaction method.

1. Identify the species reduced, the species oxidized, and any spectator ions 2. Separate the reaction into two half-reactions, omitting any spectator ions 3. Balance the charges in each half-reaction by adding electrons to each 4. Balance the electrons by multiplying each half-reaction 5. Add the two half-reactions together, ensuring that electrons cancel

steps for determining molecular shape in the correct order, starting with the first step at the top of the list.

1. Use the molecular formula to draw a Lewis structure 2.Count the number of electron domains on the central atom 3.Determine the electron domain geometry by applying the VSEPR model 4.Determine the molecular shape by considering the position of the atoms only

the steps in order for determining the molecular formula of a compound from combustion analysis data, if the approximate molar mass is known.

1. determine the empirical formula of the compound from the combustion analysis data 2. use the empirical formula to calculate the empirical molar mass 3. divide the approximate molar mass of the compound by the empirical molar mass, and round the quotient to the nearest integer 4. multiply each subscript in the empirical formula by the integer obtained

the steps necessary to determine the empirical formula of a compound from combustion analysis data.

1. determine the masses of C and H from the masses of CO2 and H2O 2. determine the mass of O, if present, by subtracting the masses of C and H from the total mass oof the initial sample 3. convert the subscripts in the formula to whole numbers, by dividing each by the smallest subscript 4. determine the number of moles of each element in the compound, and use the results as subscripts in a chemical formula

Why is BeF2 a nonpolar molecule?

BeF2 is linear and therefore the individual bond dipoles cancel to give no net dipole.

Which statement does NOT correctly describe a step in determining the empirical formula of a compound from combustion analysis data?

Determine the mass of a third element, if present, from the mass of its oxide produced in the combustion.

A student has done experiments to determine the empirical formula and the approximate molar mass of a substance. Which of the following methods should be used to determine the molecular formula?

Divide the approximate molar mass by the empirical formula mass.

the basic principle of the VSEPR theory

Each group of valence electrons around a central atom is located as far from the others as possible.

True or false: The term "weak" can be used to describe a solution that has a small ratio of solute to solvent.

False

Which statement below correctly describes the process depicted in the following balanced equation? C3H7OH (l) →Δ→ΔC3H7OH (g)

Heat is being used to vaporize liquid propanol, C3H7OH.

spectator ions

Ions that do not participate in the reaction although they are present

balanced equation that correctly represents the dissociation of K2SO4 in water?

K2SO4 (s) → 2K^+ (aq) + SO4^2- (aq)

A sample of an organic compound that contains C, H, and O is subjected to combustion analysis in order to determine the percent composition of the compound. Which statement about the information gained in the process is NOT correct?

The mass of oxygen in the sample is equal to the mass of oxygen contained in the CO2 and H2O collected in the experiment.

A neutralization reaction occurs between a(n) _____ and a(n) _____ .

acid; base

actual yield

amount of product experimentally obtained from a chemical reaction

The molecular shape of a species, which is the arrangement of the bonded atoms around the central atom, is determined not only by the number of ______ electron domains that join the atoms, but by the number of ______ electron domains as well, since these electrons also occupy space.

bonding; nonbonding

What type of reaction is described by the equation shown below? CS2 (l) + 3O2 (g) → CO2 (g) + 2SO2 (g)

combustion

concentrated solution

describes a solution that contains a large amount of solute in a given volume

dilute solution

describes a solution that contains a small amount of solute in a given volume

nonelecytrolyte

does not dissociate/ionize at all in aqueous solution; no ions are produced and the solution does not conduct an electric current

The electron-domain geometry of a species is the arrangement of electron ______ around the central atom, whereas the molecular geometry is the arrangement of bonded ______ . Two species with the same electron-domain geometry may have different molecular geometries.

domains; atoms

A substance that conducts electricity when dissolved in water is called a(n) ______; whereas a substance that does not conduct electricity in aqueous solution is a(n) ______ .

electrolyte; nonelectrolyte

The movement of _____ from one reactant to another is the key chemical event in an oxidation-reduction or _____ reaction.

electrons; redox

Individual bond dipoles will cancel

for a species that has identical bonds and a symmetrical geometry.

Individual bond dipoles will not cancel

for a species with an unsymmetrical geometry

A species will be nonpolar overall

if individual bond dipoles cancel

A species will be polar overall

if individual bond dipoles do not cancel.

The ________ reactant in a reaction is one that limits the amount of product formed. This reactant will be completely used up in the reaction. Any reactants that are not used up are said to be ______ reactants.

limiting; excess

weak electrolyte

low % dissociation/ionization in aqueous solution; few ions are produced and the solution conducts poorly

molarity of a solution

moles of solute/liters of solution

A displacement reaction is one in which a _____ reactive metal displaces the ion(s) of a _____ reactive metal in aqueous solution.

more; less

When two polar molecules are close together, the partial positive charge on one molecule will attract the partial ______ charge on the other. This type of intermolecular force is called a _____ attraction.

negative; dipole-dipole

An acid-base reaction is also called a(n) ______ reaction because in many cases the product is a neutral solution of a soluble _____ compound, also called a salt.

neutralization; ionic

When a hydrogen atom is covalently bonded to either oxygen, ______, or fluorine there will be an attraction between that hydrogen and a lone pair ______ of on a nitrogen, oxygen, or fluorine atom on an adjacent molecule. This attraction is called a ______ bond.

nitrogen; electrons; hydrogen

Dispersion forces are the only type of intermolecular force exhibited by atoms and by ______ molecules. Without the existence of dispersion forces, such substances would only exist as _____

nonpolar; gases

A bond formed by sideways overlap of two p orbitals (one from each bonding atom) is called a(n) ______ bond. This type of bond has _____ region(s) of electron density.

pi; 2

strong electrolyte

shows 100% dissociation/ionization in aqueous solution; ions are produced and the solution conducts electricity well

A bond in which the shared electron density is concentrated along the axis between the bonding nuclei is called a(n) ______ bond.

sigma

The general reaction scheme A + BC → AC + B represents a ______ reaction, while the general reaction scheme X → Y + Z represents a ______ reaction.

single displacement; decomposition

A group of hybrid orbitals formed by the hybridization of s and p orbitals from the valence shell of an atom all have the same ______ and _______.

size; shape

A precipitation reaction is a reaction in which two or more water-_____, ionic compounds react in aqueous solution to form a(n) _____ precipitate.

soluble; solid

A solution is diluted by adding more _____, which means the _____ of the solution increases but the amount (moles) of solute stays the same.

solvent; volume

The hybridization of one s and one p orbital will result in the formation of two _____ hybrid orbitals. This will leave ______ unhybridized valence p orbital(s), which is/are at right angles to the hybrid orbitals.

sp; two

Ions that are present, but not involved in the actual chemical reaction, are called _____ ions. These ions will appear unchanged on both sides of an ionic equation.

spectator

Water-soluble hydroxides of metals from Groups 1A and 2A are _____ bases because they are ionic compounds that _____ completely in aqueous solution.

strong; dissociate

concentration

the amount of solute dissolved in a given quantity of solvent or solution

theoretical yield

the maximum possible of a product, calculated from the molar ratio in the balanced chemical reaction

A procedure in which the known concentration of one solution is used to determine the unknown concentration of another is called a(n) ______

titration

True or false: Dispersion forces are exhibited by both polar and nonpolar molecules.

true

Which of the following statements are correct interpretations of the balanced equation 4C (s) + S8 (s) → 4CS2 (l)?

•4 atoms of carbon react with 1 molecule of S8 to form 4 molecules of CS2. •4 moles of carbon react with 1 mole of S8 to form 4 moles of CS2. •Carbon and S8 are reactants and CS2 is the product.

correct interpretations of the balanced equation 4C (s) + S8 (s) → 4CS2 (l)?

•4 atoms of carbon react with 1 molecule of S8 to form 4 molecules of CS2. •4 moles of carbon react with 1 mole of S8 to form 4 moles of CS2. •Carbon and S8 are reactants and CS2 is the product.

VSPER model

•A Lewis structure is necessary in order to apply the VSEPR model. •According to this model, the valence electrons around a central atom are located as far from each other as possible. •The VSEPR model is used to predict the geometry of a covalently bonded species.

describe the formation of sp2 hybrid orbitals?

•A group of sp2 hybrid orbitals assumes a trigonal planar geometry. •The formation of sp2 hybrid orbitals leaves one unhybridized valence p orbital.

correctly describe a π bond?

•A multiple bond always contains at least one π bond. •A π bond is formed by the side-to-side overlap of two p orbitals.

correctly describe a σ bond.

•All single bonds are σ bonds. •A σ bond results from end-to-end (direct) overlap of two orbitals.

the behavior of electrolytes and nonelectrolytes.

•An electrolyte is a substance that produces ions when dissolved in water. •Nonelectrolytes are water-soluble molecular compounds.

combustion analysis

•Combustion analysis involves burning a compound in O2. •The mass of hydrogen in the compound is determined from the amount of H2O produced. •Every 1 mole of carbon in the compound will produce 1 mole of CO2.

redox reaction

•Electrons always move from an atom that attracts them less strongly. •involves the transfer of electrons. •Reduction and oxidation always occur together.

Dipole-dipole attractions

•For two compounds of similar molar mass, the greater the molecular dipole moment, the stronger the dipole-dipole attraction. •These are the forces of attraction between two polar molecules.

correctly interpret the balanced chemical equation 4HCl (aq) + MnO2 (s) → MnCl2 (aq) + 2H2O (l) + Cl2 (g)?

•HCl is a reactant in this equation. •The MnCl2 produced is dissolved in water. •Water is both a solvent and a product in this reaction.

Lewis bonding theory and valence bonding theory?

•Lewis theory does not explain differences in bond strength, while valence bond theory does. •Valence bond theory can make predictions about bond angles that Lewis theory cannot.

describe sp hybrid orbitals

•The angle between two sp hybrid orbitals is 180º •Each sp hybrid orbital has one large and one small lobe.

the changes occurring during a dilution?

•The concentration of the solution decreases. •The number of moles of solute will not change.

aspects of bonding are addressed by valence bond theory, but are NOT addressed by Lewis bond theory?

•The energetics of bond formation •The differences in length between various single bonds

decribe sp3 hybrid orbitals

•The four sp3 hybrid orbitals of a group are equivalent in shape and energy. •An sp3 hybrid orbital is unsymmetrical in shape, having one small and one large lobe.

correctly describe the limiting reactant in a reaction?

•The maximum amount of product formed is the amount that can be formed from the limiting reactant. •The limiting reactant limits the amount of product that can form.

how to determine the molecular shape of a species using VSEPR

•The total number of shared and unshared electron pairs around the central atom gives the electron-domain geometry. •Use the molecular formula to draw the Lewis structure. •If unshared electron pairs are present, the molecular geometry will differ from the electron-domain geometry.

how to balance a simple redox reaction using the half-reaction method.

•The unbalanced equation must first be separated into its half-reactions. •The two half-reactions are multiplied by coefficients as necessary in order to balance the electrons. •Electrons will not appear in the final balanced equation.

precipitation reaction

•forms one or more insoluble products. •often occurs in aqueous solution. •usually involves ionic compounds.