A flask is charged with $0\mathrm{.}140$mol of A and allowed to react to form B according to the following hypothetical gas$-$phase reaction.

The following data are collected.

$A(g)B(g)$

$\backslash$table$[[$times $($s$),0,40,80,120,160],[$moles of A$,0\mathrm{.}140,0\mathrm{.}067,0\mathrm{.}042,0\mathrm{.}031,0\mathrm{.}018]]$

$($a$)$ Calculate the number of moles of B at each time in the table.

$0$ s

mol

$40s$

mol

$80$ s

mol

$120$ s

mol

$160$ s

mol

$($b$)$ Calculate the average rate of disappearance of A for each $40s$ interval, in units of mol$/$s$.$

$0-40s$

$mo\frac{l}{s}$

$40-80s$

$mo\frac{l}{s}$

$80-120s$

$mo\frac{l}{s}$

$120-160mo\frac{l}{s}$

$mo\frac{l}{s}$