Question

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PV- nT 7 An 11.2-1 sample of gas is determined to comain 9.50 mol N2 At the sce epests and pressure, how many moles off gas would there be in a 29-4. g 10p v.zL 10.S0 mo| NG CC NS. 8. An unknown diatomic gas has a density of 3.164 g/L at STP. What is the ideendity of the Gas? (10pts)

Answer 1

7. Avogadro's law: Equal volumes of gases under the same condition of temperature and pressure have same number of particles in other world we can say one mole of any gas at the same temperature and same pressure condition have the same volume. According to Avogadro's hypothesis at STP, 1 mol of any gas contains 6.02x10- particles, occupies in 22.4 L volume. Or V1/nl=V2/ n2 Given that Vi=11.2 L nl=0.50 mole V2=20.0 L therefore 11.2 L /0.5 Mole = 20.0 L / n2 n2 = 20.0/11.2 *0.5 = 0.89 moles Standard temperature is 0° c and standard pressure is 1 atm, which is atmospheric pressure exerted by air at sea level. The volume occupies by 1 mol of any gas at STP is called the molar volume. The ideal gas law is following: PV = nRT Here, R; (0.0821 atm.L mol-'.K-) is the universal gas constant. To calculate the molar mass of any substance uses the following expression: d="exte RT Here, dis the density, u is the molar mass of arsine; R;(0.0821 atm.L moll.K-1) is the universal gas constant, pis the pressure ,1.00 atm and r is the temperature (0 0°C or 298 K) To calculate the molar mass put these values in the following expression: d=4*P 4=dx HT Il = 3.164 g/ x 0.0821 atm.K mol-x273K 1.00 am \ = 70.9 g mol" therefore the gas is Cl2