Progress Check 4

A student combines a solution of NaCl (aq) with a solution of AgNO3 (aq), and a precipitate forms. Which of the following is the balanced net ionic equation for the formation of the precipitate? a. Ag+ (aq) + Cl- (aq) -> AgCl (s) b. Na+ (aq) + NO3- (aq) -> NaNO3 (s) c. NaCl (aq) + AgNO3 (aq) -> NaNO3 (s) + AgCl (aq) d. NaCl (aq) + AgNO3 (aq) -> NaNO3 (aq) + AgCl (s)

a. Ag+ (aq) + Cl- (aq) -> AgCl (s)

A student was given two clear liquids; a colorless liquid and a dark-blue liquid. The student was asked to combine the liquids in a beaker and record observations. Which of the following results, if true, would provide the best evidence that a chemical change took place when the liquids were combined? a. The resulting mixture was cloudy b. The total volume of the mixture was equal to the sum of the initial volumes c. The resulting liquid was light blue d. The liquids formed two separate layers in the beaker

a. The resulting mixture was cloudy

Which of the following represents the oxidation half-reaction based on the balanced ionic equation shown above? a. Fe2+ (aq) + e- -> Fe3+ (aq) b. Fe2+ (aq) -> Fe3+ (aq) + e- c. MnO4- (aq) -> Mn2+ (aq) + 5 e- d. MnO4- (aq) + 5e- -> Mn2+ (aq)

b. Fe2+ (aq) -> Fe3+ (aq) + e-

Which of the following best describes the process represented above that takes place when NH3 is added to water? a. It is a single replacement reaction in which an electron pair on N is replaced with an H atom b. It is an acid-base reaction in which a proton is exchanged from H2O to NH3 c. It is a precipitation reaction in which NH4OH, an insoluble solid, is produced d. It is an oxidation-reduction reaction in which the oxidation number of N changed from -3 to -4

b. It is an acid-base reaction in which a proton is exchanged from H2O to NH3

A beaker was half filled with freshly distilled H2O and placed on a hot plate. As the temperature of the water reached 100 degrees C, vigorous bubbling was observed in the beaker. The gaseous contents of the bubbles were analyzed. The presence of which of the following substances would support the claim that the observed phenomenon was a physical change? a. H2 (g) b. O2 (g) c. CO2 (g) d. H2O (g)

d. H2O (g)

A student combines a solution of NaCl (aq) with a solution of AgNO3 (aq), and a precipitate forms. Assume that 50.0 mL of 1.0 M NaCl (aq) and a 50.0 mL of 1.0 mL of 1.0 M AgNO3 (aq) were combined. According to the balanced equation, if 50.0 mL of 2.0 M NaCl (aq) and 50.0 mL of 1.0 M AgNO3 (aq) were combined, the amount of precipitate formed could a. double, because all of the coefficients are 1 b. double, because the amount of one of the reactants are doubled c. not change, because all of the coefficients are 1 d. not change, because the amount of AgNO3 (aq) did not change

d. not change, because the amount of AgNO3 (aq) did not change

Based on the Bronsted-Lowry theory of acids and bases, which of the following species can act as both a conjugate acid and a conjugate base a. HS- b. CH3COO- c. H3O+ d. NH4+

a. HS-

A student combined two colorless aqueous solutions. One of the solutions contained Na2CO3 as the solute, and the other contained HCl. The chemical reaction that took place is represented by the equation above. What experimental result would be evidence that a chemical reaction took place when the solutions were combined? a. Bubbles formed when the two solutions were combined b. The total volume of the mixture is close to the sum of the initial volumes c. The resulting solution is colorless d. The resulting solution conducts electricity

a. Bubbles formed when the two solutions were combined

When a zinc plate is placed in an aqueous solution of copper sulfate, elemental copper forms, as represented by the equation above. Which of the following represents the reduction half-reaction of the reaction? a. Cu2+ (aq) + 2 e- -> Cu (s) b. Cu (s) -> Cu2+ (aq) + 2e- c. Zn (s) + 2 e- -> Zn2- (aq) d. Zn (s) -> Zn2+ (aq) + 2 e-

a. Cu2+ (aq) + 2 e- -> Cu (s)

2 Mg (s) + SiCl4 (l) -> 2 MgCl2 (s) + Si (s) Which of the following statements about the reaction represented above ise correct? a. It is an oxidation-reduction reaction, and Mg is oxidized b. It is an oxidation-reduction reaction, and electrons are transferred from SiCl4 to Mg c. It is an oxidation-reduction reaction, and the oxidation number of Cl changes from +4 to +2 d. It is not an oxidation-reduction reaction because none of the oxidation numbers change

a. It is an oxidation-reduction reaction, and Mg is oxidized

A student carried out a titration using HC2H3O2 (aq) and a NaOH (aq). The net ionic equation for the neutralization reaction that occurs during the titration is represented above. The NaOH (aq) was added from a buret to the HC2H3O2 (aq) in a flask. The equivalence point was reached when a total of 20.0 mL of NaOH (aq) had been added to the flask. How does the amount of HC2H3O2 (aq) in the flask after the addition of 5.0 mL of NaOH (aq) compare to the amount of HC2H3O2 (aq) in the flask after the addition of 1.0 mL of NaOH (aq), and what is the reason for this result? a. It is less because more HC2H3O2 (aq) reacted with the base b. It is the same because the equivalence point has not been reached c. It is the same because all of the coefficients in the neutralization equation are 1 d. It is greater because HC2H3O2 (aq) is a proton donor

a. It is less because more HC2H3O2 (aq) reacted with the base

Which of the following is the correct equation of the reaction that occurs when aqueous solutions of ammonia and hydrochloric acid are combined? a. NH3 (aq) + HCl (aq) -> NH4Cl (aq) b. NH3 (aq) + H+ (aq) -> NH4+ (aq) c. NH3 (aq) + HCl (aq) -> NH4+ (aq) + Cl- (aq) d. NH3 (aq) + H+ (aq) + Cl- (aq) -> NH4+ (aq) + Cl1 (aq)

b. NH3 (aq) + H+ (aq) -> NH4+ (aq)

Based on the half-reactions represented above, which of the following is the balanced ionic equation for the oxidation-reduction reaction between Al (s) and Sn2+ (aq)? a. Al (s) + Sn2+ (aq) -> Al3+ (aq) + Sn (s) + e- b. 3 Al (s) + 2 Sn2+ (aq) -> 3 Al3+ (aq) + 2 Sn (s) c. 2Al (s) + 3 Sn2+ (aq) -> 2 Al3+ (aq) + 3 Sn (s) d. Al (s) + Sn2+ (aq) + 2 e- -> Al3+ (aq) + Sn (s) + 3e-

c. 2 Al (s) + 3 Sn2+ (aq) -> 2 Al3+ (aq) + 3 Sn (s)

When students added 2.0 g of NaI crystals to 100. mL of Pb(NO3)2 (aq), a yellow precipitate formed. After the solution was filtered, the yellow solid was dried and weighed. Data from the experiment are shown in the table above. Which of the following claims is best supported by the observations? a. A physical change occurred when a new yellow compound was formed b. A physical change occurred when the color of the NaI solid added changed to yellow when mixed with water c. A chemical change occurred when a yellow, insoluble compound with a larger mass than the original NaI formed d. A chemical change occurred when covalent bonds between the yellow solid and water were broken during drying

c. A chemical change occurred when a yellow, insoluble compound with a larger mass than the original NaI formed.

A chemistry teacher carried out several demonstrations, and students recorded their observations. For one of the demonstrations, a student concluded that a physical change took place, but not a chemical change. Which of the following observations could the student have made of the results of the demonstration? a. Two colorless solutions were combined, and the resulting solution was pink b. When a solid was added to a liquid, sparks were produced c. One piece of solid substance was changed into small pieces d. When two solutions were combined, a precipitate formed

c. One piece of solid substance was changed into small pieces

A student combines a solution of NaCl (aq) with a solution of AgNO3 (aq), and a precipitate forms. Which of the following is evidence that ionic bonds formed during the precipitation? a. The resulting solution is colorless b. The resulting solution conducts electricity c. The precipitate has a high melting point d. The temperature of the solution did not change significantly during the precipitation

c. The precipitate has a high melting point

According to the balanced chemical equation above, when 100.0 mL of 0.100 M K2SO3 (aq) is mixed with 100.0 mL of 0.200 M HNO3 (aq) at 30 degrees C and 1 atm, the volume of SO2 gas produced is 0.24 L. If it is assumed that the reaction goes to completion, which of the following changes would double the volume of SO2 produced at the same temperature and pressure, and why? (For each changem assume that the other solutions and volumes remain the same.) a. Using 200.0 mL of the 0.100 M K2SO3 (aq), because it then becomes the reactant in excess b. Using 200.0 mL of the 0.200 M HNO3 (aq), because the volume of SO2 produced is inversely proportional to the number of moles at constant temperature and pressure c. Using 200.0 mL of 0.100 M K2SO3 (aq) and 200.0 mL of 0.200 M HNO3 (aq), because this provides double the number of moles with the correct stoichiometric ratio d. Using 400.0 mL of 0.100 M K2SO3 (aq) and 200.0 mL of 0.200 M HNO3 (aq), because this provides the same number of moles of each reactant

c. Using 200.0 mL of 0.100 M K2SO3 (aq) and 200.0 mL of 0.200 M HNO3 (aq), because this provides double the number of moles with the correct stoichiometric ratio

Which of the following is the correct net ionic equation of the neutralization reaction between hydroflouric acid and sodium hydroxide in aqueous solution? a. HF (aq) + NaOH (aq) -> H2O (l) + NaF (aq) b. HF (aq) + NaOH (aq) -> NaH (aq) + FOH (aq) c. H+ (aq) + OH- (aq) -> H2O (l) d. HF (aq) + OH- (aq) -> H2O (l) +F- (aq)

d. HF (aq) + OH- (aq) -> H2O (l) + F- (aq)

When the reaction represented above proceeds, heat is produced. Which of the following best describes the reaction? a. It is a combustion reaction because heat is produced by the reaction b. It is a double replacement reaction because 2 Cl atoms are added to Zn c. It is an acid-base reaction because HCl is an acid that is capable of exchanging H+ d. It is an oxidation-reduction reaction because zinc is oxidized and hydrogen is reduced

d. It is an oxidation-reduction reaction because zinc is oxidized and hydrogen is reduced