Problem 33
Is carbon monoxide isoelectronic with nitrogen \(\left(\mathrm{N}_{2}\right)\) ?
Problem 34
Describe a laboratory and an industrial preparation of nitrogen gas.
Problem 35
What is meant by nitrogen fixation? Describe a process for fixation of nitrogen on an industrial scale.
Problem 37
Why is the \(\mathrm{P}_{4}\) molecule unstable?
Problem 38
Predict the geometry of nitrous oxide \(\left(\mathrm{N}_{2} \mathrm{O}\right),\) by the VSEPR method, and draw resonance structures for the molecule. (Hint: The atoms are arranged as NNO.)
Problem 39
Potassium nitrite can be produced by heating a mixture of potassium nitrate and carbon. Write a balanced equation for this reaction. Calculate the theoretical yield of \(\mathrm{KNO}_{2}\) produced by heating \(57.0 \mathrm{~g}\) of \(\mathrm{KNO}_{3}\) with an excess of carbon.
Problem 40
Dinitrogen pentoxide is a product of the reaction between \(\mathrm{P}_{4} \mathrm{O}_{10}\) and \(\mathrm{HNO}_{3}\). Write a balanced equation for this reaction. Calculate the theoretical yield of \(\mathrm{N}_{2} \mathrm{O}_{5}\) if \(79.4 \mathrm{~g}\) of \(\mathrm{P}_{4} \mathrm{O}_{10}\) is combined with an excess of \(\mathrm{HNO}_{3}\). (Hint: One of the products is \(\mathrm{HPO}_{3}\).)
Problem 41
Consider the reaction: $$ \mathrm{N}_{2}(g)+\mathrm{O}_{2}(g) \rightleftarrows 2 \mathrm{NO}(g) $$ Given that the \(\Delta G^{\circ}\) for the reaction at \(298 \mathrm{~K}\) is \(173.4 \mathrm{~kJ} / \mathrm{mol},\) calculate (a) the standard free energy of formation of \(\mathrm{NO},(\mathrm{b}) K_{P}\) for the reaction, and (c) \(K_{\mathrm{c}}\) for the reaction.
Problem 43
When \(1.645 \mathrm{~g}\) of white phosphorus is dissolved in \(75.5 \mathrm{~g}\) of \(\mathrm{CS}_{2}\), the solution boils at \(46.709^{\circ} \mathrm{C}\), whereas pure \(\mathrm{CS}_{2}\) boils at \(46.300^{\circ} \mathrm{C}\). The molal boiling-point elevation constant for \(\mathrm{CS}_{2}\) is \(2.34^{\circ} \mathrm{C} / \mathrm{m}\). Calculate the molar mass of white phosphorus, and give the molecular formula.
Problem 44
Nitrogen can be obtained by (a) passing ammonia over red-hot copper(II) oxide and (b) heating ammonium dichromate [one of the products is \(\mathrm{Cr}(\mathrm{III})\) oxide]. Write a balanced equation for each preparation.
