In the complete combustion of $C_4H_{10}$,the number of moles of oxygen required is:

Write the reaction of aluminum with caustic soda and determine how many moles of $H_2$ gas will be produced at $STP$ from $54 \ g$ of $Al$. (in $mol$)

What is the value of percent atom economy when an organic compound of formula weight $75 \ u$ is obtained from reactants having sum formula weight $225 \ u$?

How many grams of $BaCO_3$ are produced when excess $CO_2$ is passed through $0.205 \ mol$ of $Ba(OH)_2$?

If $10 \ g$ ($90 \%$ pure) limestone is heated,what volume of $CO_2$ in liters will be obtained at $NTP$?

Upon mixing $50.0 \ mL$ of $0.1 \ M$ lead nitrate solution with $50 \ mL$ of $0.05 \ M$ chromic sulphate solution,precipitation of lead sulphate takes place. How many moles of lead sulphate are formed and what is the molar concentration of chromic sulphate left in the solution?