Chapter 2

(a) When \(4.2 \mathrm{~g} \mathrm{NaHCO}_{3}\) is added to a solution \(\mathrm{of} \mathrm{CH}_{3} \mathrm{COOH}\) weighing \(10.0 \mathrm{~g}\), it is observed that \(2.2 \mathrm{~g} \mathrm{CO}_{2}\) is released into atmosphere. The residue is found to weigh \(12.0 \mathrm{~g}\). Show that these observations are in agreement with the low of conservation of weigh. (b) If \(6.3 \mathrm{~g}\) of \(\mathrm{NaHCO}_{3}\) are added to \(15.0 \mathrm{~g} \mathrm{CH}_{3} \mathrm{COOH}\) solution. The residue is found to weigh \(18.0 \mathrm{~g}\). What is the mass of \(\mathrm{CO}_{2}\) released in this reaction.

\(1.7 \mathrm{~g}\) of silver nitrate dissolved in \(100 \mathrm{~g}\) of water is taken. \(0.585 \mathrm{~g}\) of sodium chloride dissolved in \(100 \mathrm{~g}\) of water is added to it and chemical reaction occurs. \(1.435 \mathrm{~g}\) of silver chloride and \(0.85 \mathrm{~g}\) of sodium nitrate are formed. Justify that the data obey law of conservation of mass.

\(1.08 \mathrm{~g}\) of copper wire was allowed to react with nitric acid. The resulting solution was dried and ignited when \(1.35 \mathrm{~g}\) of copper oxide was obtained. In another experiment \(2.30 \mathrm{~g}\) of copper oxide was heated in presence of hydrogen yielding \(1.84 \mathrm{~g}\) of copper. Show that the above data are in accordance with law of constant proportion.

Carbon and oxygen are known to form two compounds. The carbon content in one of these is \(42.9 \%\) while in the other it is \(27.3 \%\). Show that this data is in agreement with the law of multiple proportions.

Calculate the mass in \(\mathrm{g}\) of : (a) \(2 \mathrm{~g}\) -atom of \(\mathrm{Mg}\) (b) \(3 N\) atoms of \(\mathrm{Mg}\).

What is the weight of one atom of \(\mathrm{H}\) in \(\mathrm{g}\) (at.wt. of \(\mathrm{H}=1.008\) )?

How many nitrogen atoms are in \(0.25\) mole of \(\mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2} ?\)

How many \(g\) atoms of \(S\) are present in \(4.9 \mathrm{~g} \mathrm{H}_{2} \mathrm{SO}_{4} ?\)

For a precious stone, 'carat' is used for specifying its mass. If 1 carat \(=3.168\) grains (a unit of mass) and 1 gram \(=15.4\) grains, find the total mass in kilogram of the ring that contains a \(0.500\) carat diamond and \(7.00\) gram gold.

Vanadium metal is added to steel to impart strength. The density of vanadium is \(5.96 \mathrm{~g} / \mathrm{cm}^{3}\). Express this in \(\mathrm{Sl}\) unit \(\left(\mathrm{kg} / \mathrm{m}^{3}\right)\)