A gas mixture contains only $He$ and $N_2,$ has a total pressure of $1\mathrm{.}67$atm, andcontains $15$mol of gas. If the partial pressure of He is $0\mathrm{.}44$atm, how many moles of He are in the mixture?

If you ever want to do some 'chemistry' with little kids, baking soda and vinegar is an old standby. This reaction is good for volcanoes, rockets, fizzy paints, or just a giant, foaming food coloring mess. Always a good time. Sodium bicarbonate and acetic acid react to form sodium acetate, carbon dioxide, and water based on the following equation.

$NaHC{O}_{3(s)}+H{C}_2{H}_3{O}_{2(aq)}Na{C}_2{H}_3{O}_{2(aq)}+C{O}_{2(g)}+H_2{O}_{(l)}$

A $10\mathrm{.}142g$ sample of $NaHC{O}_{3(s)}$ reacts with excess $H{C}_2{H}_3{O}_{2(aq)}.$ The carbon dioxide produced is collected over water. The total volume of wet gas collected is $L$ at $23\mathrm{.}3C$ and $692$ torr. The vapor pressure of water at this temperature is $31$ torr.

Write your answer as $1\mathrm{.}23L$