(Solved): A chemistry graduate student is given 450 . mL of a 1.60M benzouc acid (HC6H5CO2) sclution ...

A chemistry graduate student is given 450 . mL of a $1.60\mathrm{M}$ benzouc acid $\left({\mathrm{HC}}_6{\mathrm{H}}_5{\mathrm{CO}}_2\right)$ sclution. Benzoic acid is a weak acid with ${\mathrm{K}}_a=6.3\times 10^{?5}$. What mass of ${\mathrm{KC}}_5{\mathrm{H}}_5{\mathrm{CO}}_2$ should the student dissolve in the ${\mathrm{HC}}_6{\mathrm{H}}_3{\mathrm{CO}}_2$ solution to turn it into a butfer with $\mathrm{pH}=430$ ? You may assume that the volume of the solution doesnt change when the ${\mathrm{KC}}_6{\mathrm{H}}_5{\mathrm{CO}}_2$ is dissolved in it, Be sute your answer has a unit symbol, and round it to 2 significant digits A chemistry graduate student is given $250.\mathrm{mL}$ of a $1.20\mathrm{M}$ ammonia $\left({\mathrm{NH}}_3\right)$ solution. Ammonia is a weak base with ${\mathrm{K}}_3=1.8\times 10$. What mass of ${\mathrm{NH}}_4{\mathrm{Br}}^{?5}$ should the stubent dissolve in the ${\mathrm{NH}}_3$ solution to turn it into a bulfer with $?\mathrm{pH}=9.27$ ? You may assume that the volume of the soluthon qhesn't thange when the ${\mathrm{NH}}_4\mathrm{Br}$ is dissolved in it. Be sure your answer has a unit symbol, and round it to 2 significant dipts: