Some Basic Conc...

A mixture of calcium and magnesium carbonates weighing 1.4 g was strongly heated until no further loss of weight was perceived. The residue weighed 0.76 g. What percentage of $$MgCO_3$$ was present in the mixture?

The number of g-atom of oxygen in $$6.02\times { 10 }^{ 24 }$$ $$CO$$ molecule is

Law of constant composition is same as the law of:

Modern shoe soles are made of

If 100 gm of salt solution contains 20 g of salt dissolved in it, the percentage of the mass of the solution is________.

How many grams of $$NaOH$$ will be required to prepare $$500\ g$$ solution containing $$10$$% $$\dfrac {w}{w}NaOH$$ solution?

$$5.0\ g$$ sample of urea when heated with $$NaOBr$$ and $$NaOH$$ gives $$1120\ ml$$ of nitrogen at STP. The percentage purity of the sample is:

Sodium reacts with excess oxygen to form sodium oxide.A student wants to prepare 1.24 g of sodium oxide.While doing the calculations, he uses atomic number of sodium instead of obtained due to this mistake?

The number of gram molecule of oxygen in $$6.02 \times 10^{24}$$ CO molecules is :

A solution has $$0.05\ M - Mg^{+2}$$ and $$0.05M - NH_{3}$$. Calculate the minimum concentration of $$NH_{4}Cl$$ required to prevent only precipitation of $$Mg$$ as $$Mg(OH)_{2}\cdot K_{sp}$$ of $$Mg(OH)_{2} = 9\times 10^{-12}$$ and $$K_{b}$$ of $$NH_{3} = 1.8\times 10^{-5}$$.