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# Ideal gas law practice mccpot

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### Ideal gas law practice mccpot

1. 1. Ideal Gas LawPV = nRT<br />Application of PV=nRT<br />Density <br />Molecular Mass<br />
2. 2. Ideal Gas Law<br /><ul><li>By combining the gas laws we can write a general equation</li></ul>where<br /><ul><li>P is the pressure , V is the volume, n is the amount of gas in mole, and T(K) is the temperature
3. 3. The constant is shown byR, gas Law constant . </li></ul>The value of R, depends on the units of P & V<br /><ul><li>R =0.08206[(atm.L)/(mol.K)], when P is in atm and V is in L</li></li></ul><li>Example: How many moles of gas are in a basketball with total pressure 24.3 psi, volume of 3.24 L at 25°C?<br /><ul><li>V = 3.24 L, P = 24.3 psi, t = 25 °C and n=? Mol
4. 4. T(K) = 273.15+ t(0C) 1atm= 14.7 psi
5. 5. R= 0.08206 (atm.L)/(mol.K) </li></ul>2<br />1<br />Knowing PV= nRT, Rearrange the equation to :<br />3<br />
6. 6. Standard Conditions<br />The Standard Temperature & pressure, STP is when<br />Standard pressure = 1 atm<br />Standard temperature = 273 K, 0 °C<br />1 mole of any gas at STP condition has a volume equal to 22.4 L<br />
7. 7. Molar Volume = Volume of 1 mole of a gas<br />Solving the ideal gas equation for the volume of 1 mole of any gas at STP gives a volume of 22.4 L<br />1 mole of a gas has 6.022x1023 molecules of gas<br />6.022x1023 molecules of gas occupies a volume of 22.4L at STP<br />Molar volume of a gas at STP is 22.4 L<br />One mole of different gases have the same volume at same temperature and pressure, but have different masses <br />
8. 8. Molar Volume and Molar mass<br />4.0 g 131.23 g 16.05 g<br />6.022x1023atomsHe6.022x1023atomsXe 6.022x1023 moleculesCH4<br />Different molar mass, same molar volume at same T &P<br />
9. 9. Example 2: A gas occupies 10.0 L at 44.1 psi and 27 °C. Calculate the volume this gas occupies at standard conditions using Ideal Gas law<br />V1 =10.0L, P1= 44.1psi, t1= 27°C, P2 =1.00atm, t2=0°C and V2=?L<br />T(K) = 273.15+ t(0C) 1atm= 14.7 psi<br /> PV= nRT and R= 0.08206 (atm.L)/(mol.K)<br />
10. 10. Example 2: Calculate the volume occupied by 637 g of SO2 (MM 64.07) at 6.08 x 104 mmHg and –23 °C<br />mSO2 = 637 g, P = 6.08 x 104 mmHg, t= −23 °C, &V=?L<br />1 atm= 760 mmHg 1 mole of SO2 = 64.07 g SO2 T(K) = 273.15+ t(0C) <br /> PV= nRT & R= 0.08206 (atm.L)/(mol.K)<br />
11. 11. Density at Standard Conditions<br />Density is the ratio of mass to volume<br />Density of a gas is generally given in g/L<br />The mass of 1 mole = molar mass<br />The volume of 1 mole at STP = 22.4 L<br />Example: Calculate the density of N2(g) at STP<br />
12. 12. Gas Density<br /><ul><li>Density is directly proportional to molar mass
13. 13. As Molar mass of a gas increases, its density is also increase when T, n, P, & V are constant </li></li></ul><li>Example : Calculate the density of N2 at 125°C and 755 mmHg<br /><ul><li> P = 755 mmHg, t = 125 °C, dN2 = ?g/L
14. 14. 1 atm =760 mmHg, 1mole N2=28.0g N2, T(k) = 273.15 + t(0C)</li></li></ul><li>Example2: Calculate the density of a gas at 775 torr and 27 °C if 0.250 moles weighs 9.988 g<br /><ul><li> m = 9.988g, n = 0.250 mol, P = 1.0197 atm, T = 300.K </li></ul>Density= ?g/L<br /><ul><li>1atm =760 mmHg, T(K)=273.15+t(0C), PV=nRT, & d=(m/v)</li></li></ul><li>Molar Mass of a Gas<br /><ul><li>One of the methods chemists use to determine the molar mass of an unknown substance is to heat a weighed sample until it becomes a gas, measure the temperature, pressure, and volume, and use the ideal gas law to calculate the number of moles, then</li></li></ul><li>Example: Calculate the molar mass of a gas with mass 0.311 g that has a volume of 0.225 L at 55°C and 886 mmHg<br />m=0.311g, V=0.225L, P=1.1658 atm, T=328 K, molar mass= ? g/mol<br />1atm =760 mmHg, T(K)=273.15+t(0C), PV=nRT, & Molar Mass =(mass/n) g/mole<br />
15. 15. What is the molar mass of a gas if 12.0 g occupies 197 L at 3.80 x 102 torr and 127 °C?<br />m = 12.0g, V = 197 L, P = 0.50 atm, T =400 K, <br /> molar mass= ?g/mol<br />1atm =760 mmHg, T(K)=273.15+t(0C), PV=nRT, & Molar Mass =(mass/n) g/mole<br />