Most of Chemistry Unit 4

Al -> Al + 3e- Zn + 2e- -> Zn The half-reactions for the oxidation reaction between Al and Zn are represented above. Based on the half-reactions, which is the coefficient for Al if the equation for the oxidation-reduction reaction is balanced with the smallest whole-number coefficients?

2

A reaction in which the same reactant undergoes both oxidation and reduction (see page 2 #4)

3Br2 + 6OH -> 5Br + BrO3 +3H2O

C3H8 + O2 -> CO2 + H2O When the equation for the reaction representation above is balanced and all coefficients are reduced to the lowest whole-number terms, the coefficient for O2 is

5

In an oxidation-reduction reaction that is also a synthesis reaction

Ag + 2NH3 -> [Ag(NH3)2]

A precipitation reaction (see page 2 #3)

Ca2 + SO4 -> CaSO4

See question 5

GOOD JOB

Equal volumes of 0.2 M solutions of lead(II) nitrate and postassium bromide are combined to form lead(II) bromide as a yellow precipitate. Which of the following is the correct net ionic equation for the reaction?

Pb(2+) + 2Br- -> PbBr2

A student was asked to formulate a hypothesis about what would happen if 100 mL of 0.1 M NaOH at 25 *C was combined with 100 mL of 0.1 M MgCl2 at 25 *C. What hypothesis indicates that the student thought a chemical change would occur?

The resulting solution would precipitate

See question 19

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HCl + H2O --> H3O+ + Cl- For the dissolution of HCl in water represented above, which of the following pairs includes the Bronsted-Lowry bases?

H2O and Cl-

2 Na2O2 + S + 2H2O -> 4NaOH + SO2 Atoms of which elements reduced in the reaction?

O in Na2O2; each atom gains one electron

Cu + 2AgNO3 --> Cu(NO3)2 + 2Ag The reaction between solid copper and aqueous silver nitrate produces solid silver and a blue solution, as represented by the balanced equation shown above. Based on the balanced equation, which of the following identifies the oxidation and reduction half-reactions?

Oxidation Half-Reaction = Cu -> Cu(2+) + 2e- Reduction Half-Reaction = Ag(+) + e- -> Ag

2H2O + 4MnO4 + 3CIO2- -> 4MnO2 + 3CIO4 + 4OH-

0.0030 mol

If 0.40 mol of H2 and 0.15 mol of O2 were to react completely as possible to produce H2O, what mass of reactant would remain?

0.20 g of H2

H2 + F2 -> 2HF In the reaction represented above, what mass of HF is produed by the reaction of 3.0 x 10^23 molecules of H2 with excess F2? (Assume the reaction goes to completion.)

20. g

HSO4- + H2O -> H3O+ + SO4(2-) In the equilibrium represented above, the species that act as bases include which of the following? I. HSO4- II. H2O III. SO4

II and III

When C2H4 reacts with H2, the compound C2H6 is produced, as represented by the equation above. The reaction is correctly classified as what type? (See page 13 # 17)

Oxidation-reduction, because H2 is oxidized

I2 + C6H8O6 -> C6H6O6 + I2 + 2H The compound C6H8O6 reacts with I2 according to the reaction represented by the equation above. The reaction correctly classified as which of the following types?

Oxidation-reduction, because I2 is reduced.

In what species does sulfur have the same oxidation number as it does in H2SO4?

SO2Cl2

2F2+2NaOH->OF2+2NaF+H2O A 2 mol sample of F2 reacts with excess NaOH according to the equation above. If the reaction is repeated with excess NaOH but with 1 mol of F2, which of the following is correct?

The amount of OF2 produced is halved.