For each of the following balanced oxidation-reduction reactions,
(i) identify the oxidation numbers for all the elements in the reactants and products and
(ii) state the total number of electrons transferred in each reaction.
(a) \(2 \mathrm{MnO}_{4}^{-}(a q)+3 \mathrm{~S}^{2-}(a q)+4 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 3 \mathrm{~S}(s)+ 2 \mathrm{MnO}_{2}(s)+8 \mathrm{OH}^{-}(a q)\)
(b) \(4 \mathrm{H}_{2} \mathrm{O}_{2}(a q)+\mathrm{Cl}_{2} \mathrm{O}_{7}(g)+2 \mathrm{OH}^{-}(a q) \longrightarrow 2 \mathrm{ClO}_{2}^{-}(a q)+ 5 \mathrm{H}_{2} \mathrm{O}(l)+4 \mathrm{O}_{2}(g)\)
(c) \(\mathrm{Ba}^{2+}(a q)+2 \mathrm{OH}^{-}(a q)+\mathrm{H}_{2} \mathrm{O}_{2}(a q)+2 \mathrm{ClO}_{2}(a q) \longrightarrow \mathrm{Ba}\left(\mathrm{ClO}_{2}\right)_{2}(s)+2 \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{O}_{2}(g)\)
Text Transcription:
2 MnO4 -(aq) + 3 S2 - (aq) + 4 H2O(l) \longrightarrow 3 S(s) + 2 MnO2(s) + 8 OH-(aq)
4 H2O2(aq) +Cl2O7(g) +2 OH-(aq) \longrightarrow 2 ClO2 -(aq)+ 5 H2O(l) + 4 O2(g)
Ba2+(aq) + 2 OH-(aq) + H2O2(aq) + 2 ClO2(aq) \longrightarrow Ba(ClO2)2(s) + 2 H2O(l) + O2(g)
Step 1 of 5) Thus, cancerous cells are more susceptible to destruction by radiation than healthy ones, allowing radiation to be used effectively in the treatment of cancer. As early as 1904, physicians used the radiation emitted by radioactive substances to treat tumors by destroying the mass of unhealthy tissue. The treatment of disease by high-energy radiation is called radiation therapy. Many radionuclides are currently used in radiation therapy. Some of the more commonly used ones are listed in Table 21.10. Most of them have short half-lives, meaning that they emit a great deal of radiation in a short period of time. The radiation source used in radiation therapy may be inside or outside the body. In almost all cases, radiation therapy uses gamma radiation emitted by radioisotopes. Any alpha or beta radiation that is emitted concurrently can be blocked by appropriate packaging.
