Chem Exam 2

What are the products of the neutralization of an acid with a carbonate or sulfite that remove ions from solution by forming molecular compounds?

A gas and water

Which of the following are considered bases? Select all that apply.

Na2O Ca(OH)2 NH3

What is the product of a reaction between a strong acid and a sulfite ion (which acts as a base)?

SO2

Combination

X + Y → Z

The species reduced shows a(n)

decrease in oxidation number.

Which of the following are decomposition redox reactions? Select all that apply.

-2NO2 (g) → N2 (g) + 2O2 (g) -2H2O2 (aq) → 2H2O (l) + O2 (g)

Which of the following are combination redox reactions? Select all that apply.

-3Mg (s) + N2 (g) → 3Mg3N2 (s) -2CO (g) + O2 (g) → 2CO2 (g)

Which of the following are combination redox reactions? Select all that apply.

-C2H2 (g) + 2H2 (g) → C2H6 (g) -2K (s) + Br2 (l) → 2KBr (s)

Select all the reactions in which the oxidation numbers of the reactant species change, that is, are redox reactions.

-Co (s) + Cl2 (g) → CoCl2 (s) -7O2 (g) + 2C2H6 (l) → 4CO2 (g) + 6H2O (l)

Which of the following reactions will not occur as written? Select all that apply.

-I2 (s) +KCl (aq) → 2KI (aq) + Cl2 (g) -Br2 (I) + 2NaCl (aq) → 2NaBr(aq) +Cl2 (g) -2Br− (aq) +Cl2 (g) → Br2 (I) + 2Cl− (aq) -Br2 (I) + 2NaI (aq) → 2NaBr (aq) + I2 (s)

In the Bronsted-Lowry acid-base definition, an acid is a molecule (or ion) that _____ a proton and a base is a molecule (or ion) that _____ a proton. Multiple choice question.

donates accepts

The reaction 2H2 (g) + O2 (g) → 2H2O (l) is a redox reaction although it does not involve any ionic species. How are electrons transferred in this type of reaction?

-Electrons "move" as nonpolar covalent bonds are replaced by polar covalent bonds. Electrons shift away from H toward O as the product is formed.

Select the correct statements regarding the combustion reactions. Select all that apply.

-Elemental oxygen is a reactant. -Combustion reactions are always redox reactions. -Hydrocarbons and their oxygen-containing derivatives combust to produce CO2 and water.

Place the halogens in order from most reactive (at the top) to the least reactive.

-F2 -Cl2 -Br2 -i2

Select all the reactions that are redox reactions.

-FeCl3(aq) + Al(s) → AlCl3(aq) + Fe(s) -Ca(s) + 2H2O(l) → Ca2+(aq) + H2(g) + 2OH-(aq)

Select all the statements that correctly describe the following redox reaction, which is given as a molecular equation: Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g)

-H+ is reduced to H2. -H+ is the oxidizing agent. -Mg is oxidized to Mg2+.

Match each element with its most common oxidation number (assuming it is involved in a polar/ionic bond).

-2 : O, in compounds other than peroxides +1 : H when bonded to other nonmetals -1 : F +2 : Mg

Which of the following are decomposition redox reactions? Select all that apply.

-2NO2 (g) → 2NO (g) + O2 (g) -2KClO3 (s) → 2KCl (s) + 3O2 (g)

Which of the following statements correctly describe the activity series for metals? Select all that apply.

-Metals high on the list react more easily with cold water than metals low on the list. -Metals become less reactive the farther down the series you go. -A metal higher up in the list will displace the ions of another metal farther down the list from solution.

Which of the following reactions are expected to occur as written, with reference to the activity series for metals (shown)? Select all that apply.

-Mg (s) + Co(NO3)2 (aq) → Co (s) + Mg(NO3)2 (aq) -Pb (s) + 2HCl (aq) → PbCl2 (s) + H2 (g)

Which of the following statements correctly describe a redox reaction? Select all that apply.

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

In which of the following examples has the oxidation number (O.N.) of the given element been assigned correctly? Select all that apply.

-The O.N. for iron in FeO is +2. -The O.N. for chlorine in the ion ClO3- is +5.

How do the equations differ for the neutralization reaction between a strong acid/strong base and a weak acid/strong base?

-The anion of the weak acid is a product, not a spectator ion. -The weak acid reactant must appear as an undissociated, intact molecule in the equation.

The concentration of Fe2+ in 15.00 mL of a water sample is determined by titration with aqueous KMnO4. The balanced net ionic equation is given by: MnO4- (aq) + 5Fe2+ (aq) + H+ (aq) → 5Fe3+ (aq) + Mn2+ (aq) + 4H2O (l) It requires 2.45 mL of 0.021 M KMnO4 solution to reach the endpoint, when the purple solution becomes colorless. Which of the following options correctly describe the analysis of the Fe2+ in the water sample?

-The concentration of Fe2+ is 0.017 M. -There are 2.6 × 10-4 moles of Fe2+ in the water sample.

Which of the following options correctly describe the products of the reaction between a strong acid and a strong base in aqueous solutions? Select all that apply.

-The reaction forms a salt and water. -The net ionic equation is typically given by H+ (aq) + OH- (aq) → H2O (l).

Which of the following statements correctly describe the rules for assigning oxidation numbers (abbreviated as O.N.)? Select all that apply.

-The sum of the oxidation numbers for the atoms in a neutral compound is zero. -The O.N. for a monatomic ion is the same as its charge.

A compound is described as a strong acid. What does this term mean? Select all that apply.

-There are no intact molecules of the compound remaining in solution. -The compound ionizes completely in water.

Select the correct statements that describe a double-displacement reaction.

-They are also called "metathesis reactions." -They involve two reactant compounds exchanging bonding partners. -They are not redox reactions.

An oxidation number is the _____ an atom would have if all bonds involved the _____ of electrons. The oxidation number can be used to track movement of electrons in chemical reactions.

-charge -transfer

The reaction C8H18 (l) + O2 (g) → CO2 (g) + H2O (g) is called a(n)_________ reaction because it involves the reaction of a substance with________ gas.

-combustion -oxygen

According to the Bronsted-Lowry acid-base definition, an acid is a molecule (or ion) that________ a proton and a base is a molecule (or ion) that_________ a proton.

-donates -receives

The movement of one or more_________ from one reactant to another is the key chemical event in an oxidation - _________________ reaction, also called a(n) ___________reaction

-electron -reduction -redox

During the titration of an acid with a base, the point is the point at which the amount of ions in the original acid solution will have reacted with the amount of OH- ions from the basic solution.

-equivalence -H+ -same

A(n)__________ acid or base will dissociate completely in water, whereas a(n)_________ acid or base dissociates very little in water.

-strong -weak

The mass percent of alcohol (46.07 g/mol) in a 10. g sample of blood can be determined by titration with aqueous K2Cr2O7. The net ionic equation is given by: 2Cr2O72- (aq) + 3C2H5OH (aq) + 16H+ (aq) → 4Cr3+ (aq) + 3CH3COOH (g) + 11H2O (l). It requires 7.36 mL of 0.0177 M K2Cr2O7 solution to reach the endpoint. What is the mass percent of alcohol? (Legal intoxication is 0.080% in most states.)

0.090%

The concentration of OH- ions in a 0.62 M solution of Ca(OH)2 is equal to _____.

1.2 M

How many milliliters of 0.120 M H2SO4 are needed to neutralize a solution containing 0.250 g of NaOH (40.00 g/mol)?

26.0 mL

A chemist measures out 25.00 mL of 0.14 M HCl. Solve for both the number of moles of H+ ions and the actual number of H+ ions in this sample.

3.5 x 10-3 mol H+ 2.1 x 1021 H+ ions

How many milliliters of 0.120 M H3PO4 are needed to neutralize a solution containing 0.750 g of KOH (56.11 g/mol)?

37.1 mL

Which of the following options gives the correct total ionic equation for the reaction between an aqueous solution of the weak acid HF and strong base aqueous potassium hydroxide, KOH?

HF (aq) + K+ (aq) + OH- (aq) → H2O (l) + F- (aq) + K+ (aq)

Which of the following options gives the correct net ionic equation for the reaction between an aqueous solution of the weak acid HNO2 and aqueous lithium hydroxide, LiOH?

HNO2 (aq) + OH- (aq) → H2O (l) + NO2- (aq)

Which of the following is produced by a reaction between a strong acid and a carbonate ion (which acts as a base)? Multiple choice question.

CO2

Which combination of substances will result in a spontaneous redox reaction?

Ca (s) + ZnCl2 (aq)

Which of the following reactions is incorrectly matched with its redox type?

CaCO3 (s) → CaO (s) + CO2 (g) ⇒ Decomposition redox reaction

An acid can be defined as a substance that produces_____ ions when dissolved in water, while a base produces______ ions in aqueous solutions.

H+ OH-

In the acid-base reaction H3O+ + OH- → 2H2O, the H3O+ ion transfers a(n)_______ to the OH- ion. An acid-base reaction can therefore be described as a(n) __________-transfer process.

H+ proton

Metals participate in two types of single-displacement reactions. A reactive metal can displace _____ gas either from water or from an aqueous acid. A _____ reactive metal can also displace the ion of a _____ reactive metal from solution.

H2; more; less

When HCl reacts with an ionic carbonate, the resulting carbonic acid, H2CO3, decomposes and the products include gaseous _____ and the neutral molecule _____.

H2O CO2

Which of the following correctly predicts the final products for the following reaction? 2HNO3 (aq) + CaCO3 (s) →

H2O (l) + CO2 (g) + Ca(NO3)2 (aq)

Which of the following solutions are acidic? Select all that apply.

HBr (aq) CH3CH2COOH (aq) H3PO4 (aq)

Decomposition

Z → X + Y

Which of the following solutions is not considered to be acidic?

LiOH (aq)

Which of the following are considered bases? Select all that apply.

NH3 NaOH Ba(OH)2

Match each species to its correct oxidation number.

O in O2-> 0 Na in NaCl->+1 O in H2O-> -2 Fe in FeCl3-> +3

Which of the following features are often present in the formula of a compound that is a strong base? Select all that apply.

OH^- O^2-

Why is an acid able to produce ions in aqueous solution? Assume that the general formula of an acid is given by HA, where A is usually a halogen or oxygen atom.

The polar H-A bond breaks due to the attraction between H and the O of water.

True or false: An oxidation number is not the same as an actual charge on an ion. True false question.

True

Select the general form for a displacement type of redox reaction.

X + YZ → XZ + Y

Single displacement

X + YZ → XZ + Y

Double displacement

XY + AB → XB + AY

The ionic compound that results from the reaction between an acid and a base is called _____.

a salt

A(n)__________ releases H+ in water, therefore it must have one or more_______ atoms as part of its structure.

acid Hydrogen

A neutralization reaction occurs between a(n)______ and a(n) ________.

acid base

The_____________ is a list of metals (and hydrogen) arranged from top to bottom in order of decreasing ease of oxidation.

activity series

The term salt refers to the ionic compound formed from a neutralization reaction in which the _____ comes from the base and the _____ comes from the acid.

cation; anion

The _____ occurs in an acid-base titration when the amount (in moles) of H+ ions is brought together with the same amount (in moles) of OH- ions in the starting solution.

equivalence point

The H+ ion is not an isolated ion, but interacts strongly with H2O to produce the _________ion, which has the formula H3O+.

hydronium

An acid is a covalently bonded substance that nonetheless produces __________when dissolved in water. This occurs because the acid molecules contains a(n) _________ covalent bond between H and another atom X (such as the bond in H-Cl). The H of the acid is strongly attracted to the partially negative O atom of water. The H-X bond in the acid breaks and the acid ____________.

hydronium polar dissociates

The H+ ions produced by an acid in aqueous solution associate strongly with H2O to form the _____ ion, which has the formula _____. Multiple choice question.

hydronium; H3O+

The species oxidized shows a(n)

increase in oxidation number.

The relative reactivity of the halogens _________as one moves up Group 7A(17).

increases

When a strong acid reacts with a strong base, the products are typically a(n)__________ compound, which is called a(n)_________ , and the neutral molecule________

ionic salt water

Oxidation is defined as the _____ of electrons while reduction is the _____ of electrons.

loss gain

Oxidation is defined as the _____ of electrons while reduction is the _____ of electrons.

loss; gain

At the equivalence point of a redox titration the number of electrons _____ by the oxidized species is _____ the number of electrons _____ by the reduced species.

lost; equal to; gained

Oxidation, or the loss of electrons, will result in an element becoming _____ positive. This element will show a(n) _____ in oxidation number. Reduction, the gain of electrons, will cause an element to become _____ positive and the element will show a(n) _____ in oxidation number.

more; increase; less; decrease

An acid-base reaction is also called a(n) _____ reaction.

neutralization

A redox titration may be used to determine the unknown concentration of a reducing agent by completing reacting it with a volume of a(n) _____ of known concentration.

oxidizing agent

The species that shows a decrease in oxidation number is the

oxidizing agent.

The Bronsted-Lowry definition views an acid-base reaction as a _____ transfer reaction.

proton

The equation 3Ni2+ (aq) + 2Cr (s) → 2Cr3+ (aq) + 3Ni (s) represents a redox reaction. In this reaction Ni2+ is the species _____ and is the _____ agent.

reduced; oxidizing

The species that shows an increase in oxidation number is the

reducing agent.

The redox process in the formation of covalent compounds from their elements involves a(n) _____ of electrons from the one element to the other.

shift

A(n) _________ acid or base will dissociate completely in water, whereas a(n) ____________acid or base dissociates very little in water.

strong weak

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

titration