Problem 3
List at least three elements that are produced by electrolysis.
Problem 3
Balance these redox reactions by inspection. a) \(\mathrm{CH}_{4}+\mathrm{O}_{2} \rightarrow \mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O}\) b) \(\mathrm{P}_{2} \mathrm{O}_{5}+\mathrm{Cl}_{2} \rightarrow \mathrm{PCl}_{3}+\mathrm{O}_{2}\)
Problem 3
Which substance loses electrons and which substance gains electrons in this reaction? $$ 2 \mathrm{Mg}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{MgO} $$
Problem 4
Which substance loses electrons and which substance gains electrons in this reaction? $$ 16 \mathrm{Fe}(\mathrm{s})+3 \mathrm{~S}_{8}(\mathrm{~s}) \rightarrow 8 \mathrm{Fe}_{2} \mathrm{~S}_{3}(\mathrm{~s}) $$
Problem 4
Balance these redox reactions by inspection. a) \(\mathrm{PbCl}_{2}+\mathrm{FeCl}_{3} \rightarrow \mathrm{PbCl}_{4}+\mathrm{FeCl}_{2}\) b) \(\mathrm{SO}_{2}+\mathrm{F}_{2} \rightarrow \mathrm{SF}_{4}+\mathrm{OF}_{2}\)
Problem 4
Assign oxidation numbers to the atoms in each substance. a) lithium hydride (LiH) b) potassium peroxide \(\left(\mathrm{K}_{2} \mathrm{O}_{2}\right)\) c) potassium fluoride (KF)
Problem 5
\(\mathrm{N}\) atoms can have a wide range of oxidation numbers. Assign oxidation numbers for the \(\mathrm{N}\) atom in each compound, all of which are known compounds. a) \(\mathrm{N}_{2} \mathrm{O}_{5}\) b) \(\mathrm{N}_{2} \mathrm{O}_{4}\) c) \(\mathrm{NO}_{2}\) d) \(\mathrm{NO}\) e) \(\mathrm{N}_{2} \mathrm{H}_{4}\) f) \(\mathrm{NH}_{3}\)
Problem 5
Which substance is oxidized and which substance is reduced in this reaction? $$ 2 \mathrm{Li}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{Li}_{2} \mathrm{O}_{2}(\mathrm{~s}) $$
Problem 6
Cr atoms can have a wide range of oxidation numbers. Assign oxidation numbers for the Cr atom in each compound, all of which are known compounds. a) \(\mathrm{Na}_{2} \mathrm{Cr} \mathrm{O}_{4}\) b) \(\mathrm{Na}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\) c) \(\mathrm{CrF}_{5}\) d) \(\mathrm{CrCl}_{3}\) e) \(\mathrm{CrCl}_{2}\)
Problem 6
Balance these redox reactions by the half reaction method. a) \(\mathrm{Fe}^{3+}+\mathrm{Sn}^{2+} \rightarrow \mathrm{Fe}+\mathrm{Sn}^{4+}\) b) \(\mathrm{Pb}^{2+} \rightarrow \mathrm{Pb}+\mathrm{Pb}^{4+}\) (Hint: both half reactions will start with the same reactant.)
