Find the average rate of formation $$\mathrm{O}_{2(\mathrm{~g})}$$ in the following reaction.

$$\begin{aligned} & 2 \mathrm{NO}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{NO}_{(\mathrm{g})}+\mathrm{O}_{2(\mathrm{~g})} \\ & {\left[-\frac{\Delta[\mathrm{NO}]}{\Delta \mathrm{t}}\right]=x \mathrm{~mol} \mathrm{dm}^{-3} \mathrm{~s}^{-1}} \end{aligned}$$

Which from following is the slope of the graph of rate versus concentration of the reactant for first order reaction?

Calculate the amount of reactant in percent that remains after 60 minutes involved in first order reaction. $$\left(\mathrm{k}=0.02303\right.$$ minute $$\left.^{-1}\right)$$

The rate for reaction $$\mathrm{A}+\mathrm{B} \rightarrow$$ product, is $$1.8 \times 10^{-2} \mathrm{~mol} \mathrm{~dm}^{-3} \mathrm{~s}^{-1}$$. Calculate the rate constant if the reaction is second order in $$\mathrm{A}$$ and first order in $$\mathrm{B}$$. ($$[\mathrm{A}]=0.2 \mathrm{M} ;[\mathrm{B}]=0.1 \mathrm{M}$$)