The number of molecules in $100 \, mL$ of $0.02 \, N$ $H_2SO_4$ is .....

What does the equation $2Al(s) + \frac{3}{2}O_2(g) \to Al_2O_3(s)$ represent?

Consider the reaction shown below. The percentage yield of the amide product is $......$ . (Round off to the Nearest Integer). (Given: Atomic mass: $C = 12.0 \, u, H = 1.0 \, u, N = 14.0 \, u, O = 16.0 \, u, Cl = 35.5 \, u$)
$C_6H_5COCl + (C_6H_5)_2NH \rightarrow C_6H_5CON(C_6H_5)_2 + HCl$
Given: $0.140 \, g$ of $C_6H_5COCl$ reacts with $0.388 \, g$ of $(C_6H_5)_2NH$ to produce $0.210 \, g$ of $C_6H_5CON(C_6H_5)_2$.

The amount of anhydrous $Na_2CO_3$ present in $250 \ mL$ of $0.25 \ M$ solution is ........ $g$.

The ratio of the molar amounts of $H_2S$ needed to precipitate the metal ions from $20 \ mL$ each of $1 \ M \ Cd(NO_3)_2$ and $0.5 \ M \ CuSO_4$ is

As per the following equation,$0.217 \ g$ of $HgO$ (molecular mass $= 217 \ g \ mol^{-1}$) reacts with excess iodide. On titration of the resulting solution,how many $mL$ of $0.01 \ M$ $HCl$ is required to reach the equivalence point (in $mL$)?
$HgO + 4 I^{-} + H_2O \longrightarrow HgI_4^{2-} + 2 OH^{-}$