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FACULTY OF APPLIED SCIENCES KUALA LUMPUR CAMPUS AACB3124 Properties of Matter Tutorial 1 1. What will be the final pressure of a sample of nitrogen with a volume of 950 m 3 at 745 torr and 25.0 C if it is heated to 60.0 °C and given a final volume of 1150m3? 2. A sample of nitrogen has a volume of 880 mL and a pressure of 740 torr. What pressure will change the volume to 870 mL at the same temperature? 3. What volume in milliliters does a sample of nitrogen with a mass of 0.245 g occupy at 21 °C and 750 torr? Given that the atomic mass of nitrogen is 28.02 g mol-1 and R is 0.0821 L atm mol-1K-1. 4. A student collected a sample of a gas in a 0.220 L gas bulb until its pressure reached 0.757 atm at a temperature of 25.0 °C. The sample weighed 0.299 g. What is the molecular mass of the gas? What gas is this? Given that universal gas constant, R is 0.0821 L atm mol-1K-1, atomic mass of carbon is 12 gmol-1, atomic mass of oxygen is 16 gmol-1. 1 5. A gaseous compound of phosphorus and fluorine with an empirical formula of PF2 has a density of 5.60 g L-1 at a temperature of 23.0 °C and a pressure of 750 torr in a volume of 1L. Calculate its molecular mass and its molecular formula. Given that the atomic mass of P is 30.97 g mol-1; the atomic mass of F is 19 g mol-1. 6. Methane burns according to the following equation. CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (g) The combustion of 4.50 L of CH4 consumes how many liters of O2, both volumes measured at STP? 7. A student needs to prepare carbon dioxide gas (CO2) via the thermal decomposition of calcium carbonate (CaCO3). This decomposition process gives rise to another product known as quicklime (CaO) when it is heated strongly. (i) Write a balanced chemical equation for the reaction (ii) Determine the mass of CaCO3 would be needed to prepare enough CO2 (g) to fill a flask with a volume of 450 mL at a pressure of 750 torr and a temperature of 25 °C. Given that the atomic mass of Ca is 40.0 g mol-1, the atomic mass of C is 12.0 g mol-1, the atomic mass of O is 16.0 g mol-1. 8. How many grams of oxygen are present at 25 °C in a 5 L tank of oxygen enriched air under a total pressure of 30.0 atm when the only other gas is nitrogen at partial pressure of 15.0 atm? Given that the molecular masses of O2 and N2 are 32 g mol-1 and 28 g mol-1, respectively. 9. What are the mole fraction and the mole percent of oxygen in exhaled air if P O2 is 116 torr and Ptotal is 760 torr? 10. The hydrogen halide gases have the same general formula, HX, where X can be Cl, Br or I. If HCl (g) effuses 1.88 times more rapidly than one of the others, which hydrogen halide is the other, HBr or HI? Given that the atomic mass of hydrogen is 1 g mol-1 the atomic mass of chloride is 35.45 g mol-1 the atomic mass of bromide is 79.90 g mol-1 the atomic mass of iodide is 126.90 g mol-1 2 11. A cylinder contains 2.00 mol of helium gas at 20.0 °C. Assume the helium behaves like an ideal gas. (a) Find the total internal energy of the system, (b) What is the average kinetic energy per molecule 12. Determine the root mean square speed of the following gas at 27 °C? (a) Nitrogen (b) Oxygen Given that the atomic mass of nitrogen is 14 g mol-1 the atomic mass of oxygen is 16 g mol-1 Universal gas constant, R is 8.31 J mol-1K-1 13. The graph below shows the distribution of molecular velocities of He, H2O, N2 and O2. Identify the component of distribution A, B, C and D. Explain your answer. 14. A gas bulb of 1 litre capacity contains 2.0×1021 molecules of nitrogen exerting a pressure of 7.57×103 Nm-2. Calculate the temperature and the root mean square (r.m.s) speed of the gas molecules. Given that Avogadro constant is 6.023× 1023 mol-1 Universal gas constant, R is 8.31 J mol-1K-1 the atomic mass of nitrogen is 14 g mol-1 15. Determine the average speed, mean free path and collision frequency for molecular nitrogen with 3.7×10-10 m in diameter at 20°C and 1 atm pressure. Given that the atomic mass of nitrogen is 14 gmol-1 Universal gas constant, R is 8.31 J mol-1K-1 3