The complete combustion of one mole of benzene produces how many grams of carbon dioxide?

Which of the following reactions exhibits good atom economy according to the principles of green chemistry?

Suppose a cooking gas cylinder contains $11.2 \, kg$ of isobutane. The thermochemical equation for the combustion of butane is given below:
$C_4H_{10}(g) + \frac{13}{2} O_2(g) \to 4CO_2(g) + 5H_2O(\ell); \Delta H = -2658 \, kJ$
If a family requires $15000 \, kJ$ of energy per day for cooking,how many days will the cylinder last?

How many grams of $CaCO_3$ must be decomposed to produce $20 \ L$ of $CO_2$ at $750 \ torr$ and $27 \ ^\circ C$?

Three solutions of $HCl$ having normalities $12 \ N$,$6 \ N$,and $2 \ N$ are mixed to obtain a solution of $4 \ N$ normality. Which among the following volume ratios is incorrect for the above mixture?

The reaction of calcium with water is represented by the equation $Ca + 2H_2O \to Ca(OH)_2 + H_2$. What volume of $H_2$ at $STP$ would be liberated when $8 \ g$ of calcium completely reacts with water? .......... $cm^3$