Problem 104
The volume of a sample of pure \(\mathrm{HCl}\) gas was \(189 \mathrm{~mL}\) at \(25^{\circ} \mathrm{C}\) and \(108 \mathrm{mmHg}\). It was completely dissolved in about \(60 \mathrm{~mL}\) of water and titrated with an \(\mathrm{NaOH}\) solution; \(15.7 \mathrm{~mL}\) of the \(\mathrm{NaOH}\) solution was required to neutralize the HCl. Calculate the molarity of the \(\mathrm{NaOH}\) solution.
Problem 105
Propane \(\left(\mathrm{C}_{3} \mathrm{H}_{8}\right)\) burns in oxygen to produce carbon dioxide gas and water vapor. (a) Write a balanced equation for this reaction. (b) Calculate the number of liters of carbon dioxide measured at STP that could be produced from \(7.45 \mathrm{~g}\) of propane.
Problem 108
Nitrous oxide \(\left(\mathrm{N}_{2} \mathrm{O}\right)\) can be obtained by the thermal decomposition of ammonium nitrate \(\left(\mathrm{NH}_{4} \mathrm{NO}_{3}\right)\). (a) Write a balanced equation for the reaction. (b) In a certain experiment, a student obtains \(0.340 \mathrm{~L}\) of the gas at \(718 \mathrm{mmHg}\) and \(24^{\circ} \mathrm{C}\). If the gas weighs \(0.580 \mathrm{~g}\), calculate the value of the gas constant.
Problem 109
Describe how you would measure, by either chemical or physical means, the partial pressures of a mixture of gases of the following composition: (a) \(\mathrm{CO}_{2}\) and \(\mathrm{H}_{2}\), (b) \(\mathrm{He}\) and \(\mathrm{N}_{2}\).
Problem 110
A certain hydrate has the formula \(\mathrm{MgSO}_{4} \cdot x \mathrm{H}_{2} \mathrm{O} .\) A quantity of \(54.2 \mathrm{~g}\) of the compound is heated in an oven to drive off the water. If the steam generated exerts a pressure of 24.8 atm in a 2.00-L container at \(120^{\circ} \mathrm{C}\), calculate \(x\)
Problem 111
A mixture of \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) and \(\mathrm{MgCO}_{3}\) of mass \(7.63 \mathrm{~g}\) is combined with an excess of hydrochloric acid. The \(\mathrm{CO}_{2}\) gas generated occupies a volume of \(1.67 \mathrm{~L}\) at 1.24 atm and \(26^{\circ} \mathrm{C}\). From these data, calculate the percent composition by mass of \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) in the mixture.
Problem 112
Interstellar space contains mostly hydrogen atoms at a concentration of about 1 atom/cm \(^{3}\). (a) Calculate the pressure of the \(\mathrm{H}\) atoms. (b) Calculate the volume (in liters) that contains \(1.0 \mathrm{~g}\) of \(\mathrm{H}\) atoms. The temperature is \(3 \mathrm{~K}\)
Problem 113
If \(10.00 \mathrm{~g}\) of water is introduced into an evacuated flask of volume \(2.500 \mathrm{~L}\) at \(65^{\circ} \mathrm{C},\) calculate the mass of water vaporized. (Hint: Assume that the volume of the remaining liquid water is negligible; the vapor pressure of water at \(65^{\circ} \mathrm{C}\) is \(187.5 \mathrm{mmHg} .\) )
Problem 115
Which of the following molecules has the largest \(a\) value: \(\mathrm{CH}_{4}, \mathrm{~F}_{2}, \mathrm{C}_{6} \mathrm{H}_{6}, \mathrm{Ne}\) ?
Problem 116
The following procedure is a simple though somewhat crude way to measure the molar mass of a gas. A liquid of mass \(0.0184 \mathrm{~g}\) is introduced into a syringe like the one shown here by injection through the rubber tip using a hypodermic needle. The syringe is then transferred to a temperature bath heated to \(45^{\circ} \mathrm{C},\) and the liquid vaporizes. The final volume of the vapor (measured by the outward movement of the plunger) is \(5.58 \mathrm{~mL},\) and the atmospheric pressure is \(760 \mathrm{mmHg}\). Given that the compound's empirical formula is \(\mathrm{CH}_{2}\), determine the molar mass of the compound.
