$A$ $250 \, mL$ solution of sodium carbonate contains $5.3 \, g$ of $Na_2CO_3$. If $10 \, mL$ of this solution is taken and diluted with distilled water to $0.1 \, L$,what will be the concentration of the resulting solution?

Three substances $A$,$B$ and $C$ react to form $E$ and $D$ as shown: $2A + 3B + C \rightarrow 4D + 2E$. If the molar masses of $A, B, C$ and $D$ are $40, 30, 20$ and $15 \ g/mol$ respectively,and $570 \ g$ of a stoichiometric mixture of $A, B$ and $C$ is reacted,the maximum mass of $E$ obtained will be ............ $g$.

What is the value of percent atom economy when reactants having a sum of formula weight $78 \ u$ result in the formation of a product with a formula weight of $65 \ u$ (in $\%$)?

$A$ cylinder of gas is assumed to contain $11.2 \ kg$ of butane $(C_4H_{10})$. If a normal family needs $20000 \ kJ$ of energy per day,the cylinder will last: (Given that $\Delta H$ for combustion of butane is $-2658 \ kJ/mol$)....$days$

How many kilograms of $CaCO_3$ must be heated to obtain $56$ kilograms of $CaO$? [Atomic masses: $Ca = 40, C = 12, O = 16$]

For preparing one litre $N/10$ solution of $H_2SO_4$,we need $H_2SO_4$.......$g$.