To change the strength of $25 \, mL$ of $0.15 \, M$ $HCl$ to $0.1 \, M$,the quantity of water that is to be added is.......$mL$

The weight of calcium oxide formed by burning $20 \ g$ of calcium in excess oxygen is $.... \ g$

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

If $2 \ g$ of $NaOH$ is dissolved in water to make a $100 \ cm^3$ solution,what is the normality of this solution?

When $17 \ g$ of $H_2A$ (dibasic acid) is completely neutralized with $100 \ mL$ of $1 \ M \ BOH$ (monoacidic base),the molecular weight of the acid is:

Two elements $A$ and $B$ form $0.15 \ mol$ of $A_2 B$ and $AB_3$ type compounds. If $0.15 \ mol$ of both $A_2 B$ and $AB_3$ weigh equally,then the atomic weight of $A$ is $...$ times the atomic weight of $B$.