The temperature at which molarity of pure water is equal to its molality is:

Calculate the volume of ${\mathrm{O}}_2$ needed for combustion of $1 \mathrm{kg}$ of carbon at $\mathrm{STP}$:

$\mathrm{C}+{\mathrm{O}}_2\stackrel{\mathrm{\Delta }}{⟶}{\mathrm{CO}}_2$

$\mathrm{Li}$ metal is one of the few substances that react directly with molecular nitrogen. The balanced equation for the reaction is:

$6\mathrm{Li}\left(\mathrm{s}\right)+{\mathrm{N}}_2\left(\mathrm{g}\right)⟶2{\mathrm{Li}}_3\mathrm{N}\left(\mathrm{s}\right)$

How many grams of the product, lithium nitride, can be prepared from $3.5 \mathrm{g}$ of lithium metal and $8.4 \mathrm{g}$ of molecular nitrogen$?$

Potassium superoxide, ${\mathrm{KO}}_2$, is used in rebreathing gas masks to generate ${\mathrm{O}}_2$. If a reaction vessel contains $0.15$ mol ${\mathrm{KO}}_2$ and $0.10$ mol ${\mathrm{H}}_2\mathrm{O}$, What is the limiting reactant$?$ How many moles of oxygen can be produced?

$2{\mathrm{KO}}_2+2{\mathrm{H}}_2\mathrm{O}⟶2\mathrm{KOH}+{\mathrm{H}}_2{\mathrm{O}}_2+{\mathrm{O}}_2$

A 1 g sample of ${\mathrm{KClO}}_3$ was heated under such conditions that a part of it decomposed according to the equation.

(i) $2{\mathrm{KClO}}_3⟶2\mathrm{KCl}+3{\mathrm{O}}_2$

and the remaining underwent change according to the equation

(ii) $4{\mathrm{KClO}}_3⟶3{\mathrm{KClO}}_4+\mathrm{KCl}$

If the amount of ${\mathrm{O}}_2$ evolved was $146.8 \mathrm{mL}$ at $\mathrm{NTP}$, calculate the percentage by weight of ${\mathrm{KClO}}_4$ in the residue.