Write the reaction of aluminum with caustic soda and determine how many moles of $H_2$ gas will be produced at $STP$ from $54 \ g$ of $Al$. (in $mol$)

How much heat change in $kJ$ will occur when $233.0 \, g$ of calcium oxide reacts with sufficient carbon to produce $CaC_2$? The reaction is: $CaO_{(s)} + 3C_{(s)} \to CaC_{2(s)} + CO_{(g)}$; $\Delta H^o = 464.8 \, kJ/mol$.

One third litre of $x \ M \ K_2Cr_2O_7$ is required to completely oxidise $2 \ L$ of $0.1 \ M$ ferrous ammonium sulphate in acidic medium. What is $x$?

$4.0 \,g$ of $NaOH$ are contained in one decilitre of solution. Its molarity would be ......... $M$.

The heat of combustion of ethene $(C_2H_4)$ is $1411 \, kJ$. If a certain amount of ethene is burned to produce $6226 \, kJ$ of heat,what is the volume of $O_2$ (at $S.T.P.$) consumed in the process?

Magnetite can be reduced with $CO$ to yield iron metal and carbon dioxide. Calculate the mass of magnetite (in $kg$) needed to obtain $4 \ kg$ of iron if the process is $80 \%$ efficient. [Atomic weight of $Fe$ and $O$ are $56 \ g$ and $16 \ g$,respectively]