$1.5 \ mol$ of $O_2$ combine with $Mg$ to form oxide $MgO$. The mass of $Mg$ (atomic mass $24$) that has combined is ............. $g$.

$20.0 \ g$ of a magnesium carbonate sample decomposes on heating to give carbon dioxide and $8.0 \ g$ magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample? $(At. \ wt. \ of \ Mg = 24)$

What volume of $2 \,M \,H_2SO_4$ is required to prepare $100 \,mL$ of $0.2 \,N \,H_2SO_4$ solution (in $\,mL$)?

The density of a gas at $STP$ is $2.86 \, g \, L^{-1}$. Which of the following is the gas?

What volume of oxygen gas $(O_2)$ measured at $0\,^oC$ and $1\ atm$ is needed to burn completely $1\ L$ of propane gas $(C_3H_8)$ measured under the same conditions? $..........\ L$

Gastric juice contains about $3.0 \ g$ of $HCl$ per liter. If a person produces about $2.6 \ liters$ of gastric juice per day,find the number of antacid tablets required to neutralize all the $HCl$ produced. Consider each antacid tablet contains $400 \ mg$ of $Al(OH)_3$. [Given,atomic masses: $Al=27, O=16, H=1, Cl=35.5$]