2 Remember… Boyle’s Law Charles’ Law: Combined Gas Law: (Units MUST Match Temp in Kelvin!!!)
3 A gas with a volume of 350 ml is collected at 15o C and 120 kPa A gas with a volume of 350 ml is collected at 15o C and 120 kPa. If the temperature changes to 30o C, what pressure would be required to put this gas in a 300 ml container?
4 A balloon has a volume of 500 ml at a temperature of 22oC and a pressure of 755 mmHg. If the balloon is cooled to 0o C and a pressure of 145 mmHg, what is its new volume?
5 Avogadro’s PrincipleUnder similar conditions (same Temp and Pressure) equal volumes of gases contain equal numbers of particles.10 L of H2 (g) and 10 L of O2 (g) Both at Standard Temperature and Pressure (STP) contain…The same number of particles!
6 The volume of 1 mole of gas particles Molar VolumeThe volume of 1 mole of gas particlesat STPis 22.4 L
8 Try this: 1 mole of gas occupies 22.4 L at STP = __________ ml (22400) = ___________ moles of gas(1 mole)= ___________ particles(6.02 x 1023)
9 How many particles in 11.2 dm3 of gas at STP? 0.5 moles = 3.01 x 1023 particles22,400 cm3 of NH3 gas at STP weighs?= 22.4 L = 1 mole = 17 grams (add up MW)44.8 L of NH3 at STP weighs?= 2 moles = 34 grams_____ grams = 1 mole of nitrogen gas = _____ L at STP?28.0022.4
10 How many N2 molecules are in 22.4 dm3 at STP? = 1 mole = 6.02 x 1023What volume will 1.2 x 1024 H2 molecules occupy at STP?= 2 moles = 44.8 L at STP
11 Ideal Gas Equation Use when NOT at STP!!! PV= nRTP = Pressure (in kPa)V = Volume (in Liters or dm3)n = number of molesT = Temperature (in Kelvin)R = L• kPamole • K
13 1. What volume will 2 moles of NO2 occupy at 300 Kelvin and 90 kPa?
14 What will be the temp of 2 grams of H2 if 5000 cm3 is at 5 atm?
15 Finding Molecular Weight of a Gas Remember: MW = grams / molesConverting grams to molesDivide grams by the molecular weight
16 PV=nRT 92kPa • 5.0 L= n • 8.31 • 293 K n = 0.19 mol 1) 5.0 L of a gas weighs g at 20o C & 92 kPa. What is the mole weight of the gas?PV=nRT92kPa • 5.0 L= n • 8.31 • 293 Kn = 0.19 mol
17 2)If the mole weight of a gas is 26 g/mol and 18 2)If the mole weight of a gas is 26 g/mol and g of the gas is 30 L at 21o C, what is the pressure of the gas?PV= nRTP x 30 L=0.69 mol x 8.31 x 294 KP = 56.2kPa
18 Stoichiometry Solving Steps. Balance the Equation Change grams to molesUse mole ratio to solveChange moles to volumes
19 Use mole ratio (coefficients) Use MW on P.T. Use 22.4 L/mol @ STPOr PV = nRTUse 22.4 L/mol@ STPOr PV = nRTUse MWon P.T.
20 Mg (c) + HCl (ag) MgCl2 + H2 (g) If 2.43 g Mg react what volume of H2 is produced? (at STP)1:10.1 mole0.1 molesMg (c) HCl (ag) MgCl2 + H2 (g)2? L2.24 L H22.43 g Mg
21 Mg (c) +2 HCl (ag) MgCl2 + H2 (g) If 2.43 g Mg react what volume of H2 is produced at 40oC and 85 kPa?1:10.1 mole0.1 molesMg (c) HCl (ag) MgCl2 + H2 (g)2? L3.06 L H22.43 g Mg
22 Mg (c) + HCl (ag) MgCl2 + H2 (g) If 250 ml of H2 is produced at 20o C & 100 kPa, what mass of Mg reacted?1:10.01 mole0.01 molesMg (c) HCl (ag) MgCl2 + H2 (g)20.243 g Mg? g250 ml
23 Volume to Volume THE MOLE RATIO IS THE SAME AS THE VOLUME RATIO. Liters BUse mole ratio(coefficients)Liters A
24 What vol. of oxygen is needed to completely burn 1 L of methane? Burning of methane:What vol. of oxygen is needed to completely burn 1 L of methane?1:21.0 L2.0 LCH O2 CO2 (g) H2O (l)22
25 To produce 11.2 L of CO2 requires how many moles of O2 at STP? Burning of methane:To produce 11.2 L of CO2 requires how many moles of O2 at STP?2:11 mole =22.4 L11.2 LCH O2 CO2 (g) H2O (l)22