The vapor density of a gas is $11.2$. What is the volume occupied by $1 \, g$ of this gas at $STP$ in $L$?

$A$ $10 \ g$ effervescent tablet containing sodium bicarbonate $(NaHCO_3)$ and oxalic acid $(H_2C_2O_4)$ releases $0.25 \ L$ of $CO_2$ at $T = 298.15 \ K$ and $p = 1 \ bar$. If the molar volume of $CO_2$ is $25.0 \ L \ mol^{-1}$ under these conditions,what is the percentage by mass of sodium bicarbonate in each tablet? [Molar mass of $NaHCO_3 = 84 \ g \ mol^{-1}$,Molar mass of $H_2C_2O_4 = 90 \ g \ mol^{-1}$]

If $10$ volumes of dihydrogen gas react with $5$ volumes of dioxygen gas, how many volumes of water vapour would be produced?

Find the mass of sodium carbonate in grams required to prepare $100 \text{ ml}$ of a $0.1 \text{ M}$ aqueous solution. (Molar mass of $Na_2CO_3 = 106 \text{ g/mol}$) (in $\text{ g}$)

The amount of iron $(Fe)$ in $g$ which can be produced from $600 \ g$ of magnetite ore is [Atomic mass of $Fe$ : $55.8$]

The yield of each step as actually carried out in the laboratory is given in the reaction scheme below. Calculate the overall percentage yield of the reaction.
$Me_3C-CO-CH_3$ $\xrightarrow{58\% (A)} Me_3C-CO-CH_2Br$ $\xrightarrow{54\% (B)} Me_3C-CH(OH)-CH_2Br$ $\xrightarrow{68\% (C)} Me_3C-CH(O)CH_2$