Lead(II) oxide is obtained by roasting galena, lead(II) sulfide, in air. The unbalanced equation is:
\begin{equation}
\mathrm{PbS}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{g}) \rightarrow \mathrm{PbO}(\mathrm{s})+\mathrm{SO}_{2}(\mathrm{g})
\end{equation}
\begin{equation}
\begin{array}{l}{\text { a. Balance the equation, and determine the theoretical }} \\ {\text { yield of } \mathrm{PbO} \text { if } 200.0 \mathrm{g} \text { of } \mathrm{PbS} \text { is heated. }} \\ {\text { b. What is the percent yield if } 170.0 \mathrm{g} \text { of } \mathrm{PbO} \text { is obtained? }}\end{array}
\end{equation}