In a chemical reaction,the sum of the formula weight of all reactants is $274 \ u$ and the atom economy is $50 \%$. Calculate the formula weight of the desired product. (in $u$)

$A$ metal chloride contains $55.0 \%$ of chlorine by weight. $100 \ mL$ of vapours of the metal chloride at $STP$ weigh $0.57 \ g$. The molecular formula of the metal chloride is $...$. (Given: Atomic mass of chlorine is $35.5 \ u$)

At the same temperature and pressure,if the mass of $3 \ L$ of a hydrocarbon is equal to the mass of $3 \ L$ of $CO_2$,what is the molecular formula of the hydrocarbon?

$1.44 \ g$ of titanium (At. wt. $= 48$) reacted with excess of $O_2$ to produce $x \ g$ of a non-stoichiometric compound $Ti_{1.44}O$. The value of $x$ is:

Air contains $23\%$ oxygen and $77\%$ nitrogen by weight. What is the percentage by volume of $O_2$?

Calculate the amount of water $(g)$ produced by the combustion of $16 \ g$ of methane. (in $g$)