chapter 11 gases
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Chapter 11 Gases. Pressure and Force. ____________ (P): the force per _________ on a surface. ________ (N): the force that will increase the speed of a ___________ by _____________ each second the force is applied. ___________: a device used to measure ______________ pressure. 11-2. - PowerPoint PPT PresentationTRANSCRIPT
Chapter
11
Gases
Pressure and Force
____________ (P): the force per _________ on a surface.
________ (N): the force that will increase the speed of a ___________ by _____________ each second the force is applied.
___________: a device used to measure ______________ pressure.
11-2
Units of Pressure
Millimeters of Mercury: _________ = 1 torrAtmosphere: _______ = 760 mm HgPascal: the pressure exerted by a force of _________ acting on an area of _____________. 1 atm = 1.01325 x 105 Pa
1 atm = 101.325 KPa______: standard temperature and pressure, 0oC and 1 atm.Pounds per Square Inch (psi): 1 atm = ________
11-3
Practice
Ex. The barometer reads 758 mm Hg. What is the ________________________ in Pa?
758 mm Hg x 1.01325 x 105 Pa = 1.01 x 105 Pa 760 mm Hg
1) The air pressure in a tire is 109 kPa. What is the pressure in atm?
11-4
Dalton’s Law
________________: the pressure of each gas in a mixture of gases.
_____________: the ___________ of a gas mixture is the ______________________ of
the component gases.
PT = P1 + P2 + P3 …
11-5
Boyle’s Law_______________: the volume of a fixed mass of gas varies inversely with the pressure at constant temperature.
_________________Ex. A gas occupies a volume of ________ at a pressure of ________ and temp. _______. When the pressure is changed, the volume becomes _______. If there is no change in temp., what is the new pressure?
(1.01 KPa) (458 ml) = P2 (477 ml)
P2 = 0.970 kPa11-6
PracticeP1V1 = P2V2
2) A gas occupies a volume of 2.45L at a pressure of 1.03 atm and temp. 293 K. What volume will the gas occupy if the pressure changes to 0.980 atm and the temp. remains the same?
11-7
Charles’s Law_____________: the given value of zero in the Kelvin temperature scale. K = 273.15 + oC
_____________: the volume of a fixed mass of gas at constant pressure varies directly with the ______________.
__________Ex. What will be the volume of a gas sample at ________ if it’s volume at __________? Assume that the pressure is constant.
3.42L = V2
215K 309K
V2 = 4.92L
11-8
Practice3) A gas sample at 83oC occupies a volume of
1400m3. At what temperature will it occupy 1200m3? Assume that the pressure is
constant.
11-9
Gay-Lussac’s Law______________: the pressure of a fixed mass of gas at constant volume varies directly with the ______________.
P1 = P2
T1 T2Ex. The gas in a container is at a pressure of __________ at __________. Directions on the container warn the user not the keep it in a place where the temp exceeds ________. What would the pressure in the container be at 52oC?
3.00 atm = P2
298K 325K
P2 = 3.27 atm
11-10
Practice
P1 = P2
T1 T2
4) At 120oC the pressure of a sample of nitrogen is 1.07 atm, What will the pressure be at 205oC, assuming constant volume?
11-11
Combined Gas Law
P1 V1 = P2 V2
T1 T2____________________: expresses the relationship between pressure, volume and temp (K) of a fixed amount of gas.
Ex. A helium balloon has a volume of ________________ and _________. What volume will it have at _______________?
(1.08 atm)(50.0L) = (0.855 atm) V2
298 K 283 K
V2 = 60. L
11-12
Gas Volumes
______________________________________: at a constant temp and pressure, the ___________ of gaseous reactants and products can be expressed as ratios of small whole numbers. (____________ in balanced eq. can represent ______________!)
_________________: equal volumes of gases at the same temp. and pressure contain equal numbers of molecules.
___________
Volume = k(constant) x n(moles)
_____________________: the volume occupied by one mole of a gas at STP is 22.4L.
11-13
PracticeEx. What volume does 0.0685 mol of gas occupy at STP?
0.0685 mol x 22.4 L = 1.53 L
1 mol
Ex. What quantity of gas, in moles, is contained in 2.21 L at STP?
2.21L x 1 mol = 0.0987 mol
22.4 L
5) At STP, what is the volume of 7.08 mol of nitrogen gas?
11-14
Gas StoichGiven a volume, find a volume:
Ex. When ________ of hydrogen reacts with bromine, what volume of HBr is produced?
_________________
0.75L H2 x 2L HBr =1.5L HBr
1L H2
11-15
Practice6) What volumes of sulfur dioxide and dihydrogen sulfide gases are necessary to
produce 11.4 L of water vapor?
11-16
Gas StoichEx. How many liters of CO2 are produced at STP
when 400.00g of CaCO3 react with HCl?
CaCO3 + HCl → CaCl2 + CO2 + H2O
________________________________
400.00g CaCO3 x 1mol CaCO3 x 1mol CO2 x 22.4L
100.04g CaCO3 1mol CaCO3 1mol CO2
= ______________
11-17
Gas StoichEx. Find the mass of sugar required to produce __________ at
STP in the rxn:
C6H12O6 → 2C2H6O + 2 CO2
1.82L CO2 x 1mol CO2 x 1molC2H12O6 x 180.18gC6H12O6
22.4L 2mol CO2 1 mol
= ____________________
11-18
Ideal Gas Law_____________: the mathematical relationship
among pressure, volume, temperature and the number of moles of a gas.
Ideal Gas Law:
______________
How R (the ideal gas law constant) is derived:
R = (1 atm)(22.4L) = _________________ (1 mol)(273K)
11-19
Ideal Gas LawEx. If the pressure exerted by a gas at ____ in
a volume of ______________, how many moles of gas are present?
(5.00atm)(0.0010L) = n(0.0821atmL/molK)(273K)
n = __________________
11-20
Practice7) What volume would be occupied by 100. g
of oxygen gas at a pressure of 1.50 atm and a temp. of 25oC?
11-21
Diffusion and Effusion____________________: rates of effusion of
gases at the same temperature and pressure are __________________ to the _______________ of their molar masses.
rate of effusion of A = √MB
rate of effusion of B √MA
11-22
Diffusion and Effusion
rate of effusion of A = √MB
rate of effusion of B √MA
Ex. Compare the rate of effusion of hydrogen and oxygen at the same temp. and pressure.
rate of effusion of H2 = √32.00 g/mol = 3.98
rate of effusion of O2 √2.02 g/mol
11-23
Ch. 11TheEnd!
11-25