a.k.a ….having twice as much fun by doing twice as much math
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a.k.a ….having twice as much fun by doing twice as much math . H 2. O 2. 8 H : 8 O. Imagine that paperclips are atoms and that we’re starting with an equal number of hydrogen atoms and oxygen atoms. For example:. 2H 2 + O 2 -> 2H 2 O. - PowerPoint PPT PresentationTRANSCRIPT
a.k.a….having twice as much fun by doing twice as much math
8 H : 8 OImagine that paperclips are atoms and that we’re starting with an equal number of hydrogen atoms and oxygen atoms. For example:
Let’s assemble our paperclip atoms into paperclip molecules.
2H2 + O2 -> 2H2O
H2 O2
O2H2 H2O
The product molecules are made out of the available reactant molecules.
O2H2 H2O
Continue to convert reactants to products.
O2H2 H2O
Continue to convert reactants to products.
O2H2 H2O
Continue to convert reactants to products.
O2H2 H2O
The reaction stops after forming 4 water molecules because there aren’t any more hydrogen molecules to react.
The reaction was limited by the amount of hydrogen initially present. Therefore,
2 H2 + O2 2 H2O
O2H2
+
H2O
4 mol H2
4 mol O2
Step 1: Assume all of the hydrogen reacts and determine the number of moles of water that would be formed.
4 mol H2O
= 4 mol
8 mol H2O
Step 2: Assume all of the oxygen reacts and determine the number of moles of water that would be formed. = 8 mol
Q: How many grams of water will be formed?
Step 3: Multiply the smaller molar amount by the gfm of water to find the number of grams of water that will be formed.
A: 4 mol x 18.015 g/mol
72 g H2O
2 H2 + O2 2 H2O
For the reaction below, how many moles of water will be formed if 1.55 moles of hydrogen gas is allowed to react with 0.30 moles of oxygen gas?
What is the limiting reagent?
1.55 mol H2 1.55 mol H2O
0.30 mol O2 0.60 mol H2O
O2
Which reagent is in excess?
H2How many grams of H2O (gfm = 18.015 g/mol) will be formed from this reaction?
0.60 mol H2O x 18.015 g/mol = 10.8 g of H2O will form
For the reaction below, how many grams of water will be formed if 1.17 g of hydrogen gas is allowed to react with 7.35 g of oxygen gas?
What is the limiting reagent?
2 H2 + O2 2 H2O
g:
gfm:
mol:
1.17 g 7.35 g
2.016 g/mol 31.999 g/mol
0.58 mol
—— 0.23 mol
0.58 mol
0.46 mol
x 18.015 g/mol
8.29 g
How many grams of water will be formed? 8.29 g
And now for
something
slightly
different…
+ +
+
The Great Candy Caper!
Mission: To separate the bag of candy into three identical piles and thereby determine which type of candy is the limiting reactant.
Caution: If you eat any of the candy before telling me what the limiting reactant is, you will self-destruct.
The Great Candy Caper!
Mission: To separate the bag of candy into four identical piles and thereby determine which type of candy is the limiting reactant.
Caution: If you eat any of the candy before telling me what the limiting reactant is, you will self-destruct.
4 Al + 3O2 2Al2O3 3H2 + N2 2NH3
CH4 + 2O2 CO2 + 2H2O CH2O + O2 CO2 + H2O
2 Al + 3 PbCl2 2AlCl3 + 3Pb Zn + 2HCl ZnCl2 + H2
1.08 g Al11.12 g PbCl2 2.92 g HCl
5.23 g Zn
9.60 g O2
18.02 g CH2O
1.28 g O2
2.16 g Al11.20 g N2
0.81 g H2
6.40 g O2
6.42 g CH4
2.72 g Al2O3
4.40 g CO2
3.55 g AlCl3
4.53 g NH3
5.40 g H2O
0.081 g H2