On complete combustion at constant pressure, a 1.00-L sample of a gaseous mixture at 0C and 1.00 atm (STP) evolves 75.65 kJ of heat. If the gas is a mixture of ethane (C2H6) and propane (C3H8), what is the mole fraction of ethane in the mixture?

Define the joule in terms of SI base units.

At the critical point for carbon dioxide, the substance is very far from being an ideal gas. Prove this statement by calculating the density of an ideal gas in g/cm3 at the conditions of the critical point and comparing it with the experimental value. Compute the experimental value from the fact that a mole of CO2 at its critical point occupies 94 cm3.

In the equation w = P V, why is there a negative sign?

5-107 If 60.0 g of NH3 occupies 35.1 L under a pressure of 77.2 in. Hg, what is the temperature of the gas, in °C?

In the 1880s, Frederick Trouton noted that the enthalpy of vaporization of 1 mol pure liquid is approximately 88 times the boiling point, Tb, of the liquid on the Kelvin scale. This relationship is called Troutons rule and is represented by the thermochemical equation liquid gas H = 88 Tb, joules Combined with an empirical formula from chemical analysis, Troutons rule can be used to find the molecular formula of a compound, as illustrated here. A compound that contains only carbon and hydrogen is 85.6% C and 14.4% H. Its enthalpy of vaporization is 389 J/g, and it boils at a temperature of 322 K. (a) What is the empirical formula of this compound? (b) Use Troutons rule to calculate the approximate enthalpy or vaporization or one mole of the compound. Combine the enthalpy of vaporization per mole with that same quantity per gram to obtain an approximate molar mass of the compound. (c) Use the results of parts (a) and (b) to find the molecular formula of this compound. Remember that the molecular mass must be exactly a whole-number multiple of the empirical formula mass, so considerable rounding may be needed.

Calcium carbide, CaC2, is manufactured by reducing lime with carbon at high temperature. (The carbide is used in turn to make acetylene, an industrially important organic chemical.) Is the reaction endothermic or exothermic?

62 Ammonium dinitramide (ADN), NH4N(NO2)2, was considered as a possible replacement for aluminium chloride as the oxidizer in the solid fuel booster rockets used to launch the space shuttle. When detonated by a spark, AND rapidly decomposes to produce a gaseous mixture of N2,O2, and H2O. (This is not a combustion reaction. The ADN is the only reactant.) The reaction releases a lot of heat, so the gases are initially formed at high temperature and pressure. The thrust of the rocket results mainly from the expansion of this gas mixture. Suppose a 2.3-kg sample of ADN is denoted and decomposes completely to give N2,O2, and H2O. If the resulting gas mixture expands until it reaches a temperature of 100°C and a pressure of 1.00 atm, what volume will it occupy? Is your answer consistent with the proposed use of ADN as a rocket fuel?