A mixture of $CaCO_3$ and $MgCO_3$ weighing 1.84 g on heating leaves a residue weighing 0.96 g. If the percentage by mass of $CaCO_3$ in the original mixture is x%, what is the value of x/2?

$S{O_2}\,\, + \,\,2\,\,{H_2}S\,\, o \,\,3S\,\, + 2\,\,{H_2}O$ 2 mol of ${H_2}S$ and 11.2 L $S{O_2}$ at NTP react to form $imes$ mol at sulphur, then $imes$ is

2.24 L of a gas at STP weighs 3.2 g. The molecular weight of the gas is:

Number of molecules in 1 ml of ${O_2}$ at NTP

Volume occupied by $3.01 imes {10^{23}}\;\;$ molecules of acetylene at NTP is:

Weight of $112\,\,mL$ of oxygen at NTP on liquification would be:

The number of moles in 11.2 L at STP of oxygen