6.2 Gases Avogadro’s Theory and Molar Volume. Law of Combining Volumes (Joseph Gay –Lussac )...
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Transcript of 6.2 Gases Avogadro’s Theory and Molar Volume. Law of Combining Volumes (Joseph Gay –Lussac )...
6.2 Gases Avogadro’s Theory
and Molar Volume
Law of Combining Volumes (Joseph Gay –Lussac )
• When measured at the same temperature and pressure, volumes of gases react in simple whole number ratios.
• 2H2O(l) 2H2(g) + O2(g) (This reaction always produced twice as much hydrogen as oxygen)
http://www.carlton.paschools.pa.sk.ca/chemical/molemass/avogadro.htm
Avogadro’s Theory
• Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.
p://www.carlton.paschools.pa.sk.ca/chemical/molemass/avogadro.htm
Fill in the table below___C8H18(l) +___O2(g) ___CO2(g)+ ___H2O(g)
2 mol 25 mol mol ____mol
2 mol mol mol ____mol
___ L 25 L _____ L 18 L
8 L ____L 64 L ____L
____L 5L ____ L ____L
250 mL _____mL ____mL ____mL
Fill in the table below___C8H18(l) +____O2(g) ___CO2(g)+ ___H2O(g)
2 mol 25 mol mol ____mol
2 mol mol mol ____mol
___ L 25 L _____ L 18 L
8 L ____L 64 L ____L
____L 5L ____ L ____L
250 mL _____mL ___ mL ____mL
Fill in the table below___C8H18(l) +__ O2(g) ___CO2(g)+ ___H2O(g)
2 mol 25 mol mol ____mol
2 mol mol mol ____mol
___ L 25 L _____ L 18 L
8 L ____L 64 L ____L
____L 5L ____ L ____L
250 mL _____mL _____mL ____mL
Fill in the table below___ C8H18(l) + ___O2(g) ___CO2(g)+ __H2O(g)
2 mol 25 mol mol ____mol
2 mol mol mol ____mol
___ L 25 L _____ L 18 L
8 L ____L 64 L ____L
____L 5L ____ L ____L
250 mL _____mL ____mL ____mL
Fill in the table below2 C8H18(l) + 25 O2(g) 18 H2O(g) + 16 CO2(g) 2 mol 25 mol 18 mol 16 mol
4 mol 50 mol 36 mol 32mol
2 vol 25 vol 18 vol 16 vol
2 L 25 L 18 L 16 L
4L 50L 36 L 32 L
0.5L 6.25 L 4.5 L 4 L
Another site with VSEPR
• http://www.alevelchemistry.co.uk/module_1.htm
• General site with 3D shapes, and a variety of info.
• http://www.tannerm.com/
Molar Volume
• -The volume of one mole of any gas at a specific temperature and pressure
• @STP 22.4 L/mol
• @SATP 24.8 l/mol
• Remember STP is zero celsius and 101.3kPa
• And SATP(ambient) is 25 celsius and 100kPa
Calculations with molar volume
• n= v volume and n=m
• V molar volume M
• So v = m
• V M
Try this:
• Example 1:• What volume is occupied by 0.024 mol of
nitrogen gas at STP?(ANS: 0.54 L)
• Example 2:• How many moles of nitrogen dioxide are there in
75 L of the gas at SATP?(ANS: 3.02 mol)
Try this:
• Example 1:• What volume is occupied by 0.024 mol of
nitrogen gas at STP?(ANS: 0.54 L)
• Example 2:• How many moles of nitrogen dioxide are there in
75 L of the gas at SATP?(ANS: 3.02 mol)
Try this:
• Example 1:• What volume is occupied by 0.024 mol of
nitrogen gas at STP?(ANS: 0.54 L)
• Example 2:• How many moles of nitrogen dioxide are there in
75 L of the gas at SATP?(ANS: 3.02 mol)
• #1 Answer
• n= v 0.024 mol = __v___
• V 22.4 L/mol
• 0.54 L = v
• #2 Answer
• n= v n= 75 L
• V 24.8 L/mol
• n= 3.02 mol
• volume
• mass mol particles
• concentration
• Example #3
• What volume of balloons does 7.00 g of helium gas fill at SATP?
v=?
m= 7.00 g
M= 4.00 g/mol
V= 24.8 L/mol(Ans 43.4 L)
Practise Questions:
• P 210-211 19 0.73 L
20 5.39 x 10 5 L
21 5.09 x 10 5 L
22 2.5 x 10 5 g
15a 124 kL
15b 250L
15c 325L , 163L
Remember to use ratios