What volume of $NH_3$ gas at $STP$ would be needed to prepare $100 \ mL$ of $2.5$ molal $(2.5 \ m)$ ammonium hydroxide solution? (Assume the density of the solution is $1 \ g/mL$)

If $10^{23}$ molecules are removed from $5.6 \ L$ of an ideal gas at $273 \ K$ and $2 \ atm$ pressure,how many moles of the gas will remain?

$A$ mixture of sodium oxide $(Na_2O)$ and calcium oxide $(CaO)$ is dissolved in water and saturated with excess carbon dioxide $(CO_2)$ gas. The resulting solution is $......$ It contains $.........$ :

When $1 \ L$ of $N/5 \ HCl$ aqueous solution in a beaker is boiled,the volume of the resulting solution becomes $250 \ mL$. During this process,$3.65 \ g$ of $HCl$ is lost. What will be the concentration of the resulting solution? $(HCl = 36.5 \ g/mol)$

What quantity (in $mL$) of a $45\%$ acid solution of a mono-protic strong acid must be mixed with a $20\%$ solution of the same acid to produce $800 \ mL$ of a $29.875\%$ acid solution?

How many moles of aluminum oxide $(Al_2O_3)$ are produced when $1 \text{ mole}$ of potassium chlorate $(KClO_3)$ undergoes thermal decomposition,and the resulting gaseous product is reacted with excess aluminum?