$1.0 \ g$ of $Mg$ is burnt with $0.28 \ g$ of $O_2$ in a closed vessel. Which reactant is left in excess and how much?

For a given unbalanced reaction, $MnO_2 + HCl \rightarrow MnCl_2 + H_2O + Cl_2$, which is the limiting reagent if the initial amount for each reactant is $100 \ g$? [Molar masses: $MnO_2 = 86.9 \ g/mol$; $HCl = 36.5 \ g/mol$]

Calcium carbonate reacts with aqueous $HCl$ to give $CaCl_2$ and $CO_2$ according to the reaction given below: $CaCO_{3(s)} + 2HCl_{(aq)} \to CaCl_{2(aq)} + CO_{2(g)} + H_2O_{(l)}$
What mass of $CaCl_2$ will be formed when $250 \ mL$ of $0.76 \ M$ $HCl$ reacts with $1000 \ g$ of $CaCO_3$? Name the limiting reagent. Calculate the number of moles of $CaCl_2$ formed in the reaction.

What should be the weight and moles of $AgCl$ precipitate obtained on adding $500 \ mL$ of $0.20 \ M$ $HCl$ to $30 \ g$ of $AgNO_3$ solution (in $g$)? (Molar mass of $AgNO_3 = 170 \ g/mol$)

Dinitrogen and dihydrogen react with each other to produce ammonia according to the following chemical equation: $N_{2(g)} + 3H_{2(g)} \to 2NH_{3(g)}$
$(i)$ Calculate the mass of ammonia produced if $2.00 \times 10^3 \ g$ of dinitrogen reacts with $1.00 \times 10^3 \ g$ of dihydrogen.
$(ii)$ Will any of the two reactants remain unreacted?
$(iii)$ If yes,which one and what would be its mass?

The combustion of $1 \, \text{mol}$ of methanol in the presence of $O_2$ releases $723 \, \text{kJ mol}^{-1}$ of heat. If $1 \, \text{mol}$ of $O_2$ is used during this process,how much heat in $\text{kJ}$ will be produced?