1) Half Sheet: Write 3 things that you know about this image, 3 things you somewhat know, and 3 things you are having a difficult time with

2) Worksheet #63) QUIZ #3

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Limiting Reactant

A limiting reactant in a chemical reaction is thesubstance that • Is used up first.• Stops the reaction.• Limits the amount of product that can form.

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Reacting Amounts

In a table setting, there is 1plate, 1 fork, 1 knife, and 1 spoon.

How many table settings arepossible from 5 plates, 6 forks,4 spoons, and 7 knives?

What is the limiting item?

Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

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Reacting Amounts

Four table settings can be made.

Initially Use Left overplates 5 4 1

forks 6 4 2spoons 4 4 0knives 7 4 3

The limiting item is the spoon.

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Example of Everyday Limiting Reactant

How many peanut butter sandwiches could be made from 8 slices bread and 1 jar of peanut butter?

With 8 slices of bread, only 4 sandwiches could be made. The bread is the limiting item.

Copyright © 2008 by Pearson Education, Inc. publishing as Benjamin Cummings

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Example of Everyday Limiting Reactant

How many peanut butter sandwiches could be made from 8 slices bread and 1 tablespoon of peanut butter?With 1 tablespoon of peanut butter, only 1 sandwich could be made. The peanut butter is the limiting item.

Copyright © 2008 by Pearson Education, Inc. publishing as Benjamin Cummings

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Limiting Reactants

When 4.00 mol H2 is mixed with 2.00 mol Cl2,how

many moles of HCl can form? H2(g) + Cl2 (g) 2HCl (g)

4.00 mol 2.00 mol ??? mol• Calculate the moles of product from each reactant,

H2 and Cl2.

• The limiting reactant is the one that produces the smaller amount of product.

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Copyright © 2008 by Pearson Education, Inc. publishing as Benjamin Cummings

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Limiting Reactants Using Moles

HCl from H2

4.00 mol H2 x 2 mol HCl = 8.00 mol HCl

1 mol H2 (not possible)

HCl from Cl2

2.00 mol Cl2 x 2 mol HCl = 4.00 mol HCl

1 mol Cl2 (smaller number)

The limiting reactant is Cl2 because it is used up first. Thus Cl2 produces the smaller number of moles of HCl.

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Checking Calculations

Initially H2

4.00 mol

Cl2 2.00 mol

2HCl 0 mol

Reacted/Formed

-2.00 mol -2.00 mol +4.00 mol

Left after reaction

2.00 mol Excess

0 mol Limiting

4.00 mol

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Limiting Reactants Using Mass

If 4.80 mol Ca mixed with 2.00 mol N2, which is thelimiting reactant? 3Ca(s) + N2(g) Ca3N2(s)

Moles of Ca3H2 from Ca4.80 mol Ca x 1 mol Ca3N2 = 1.60 mol Ca3N2

3 mol Ca (Ca used up)

Moles of Ca3H2 from N2

2.00 mol N2 x 1 mol Ca3N2 = 2.00 mol Ca3N2

1 mol N2 (not possible)All Ca is used up when 1.60 mol Ca3N2 forms. Thus, Ca is

the limiting reactant.

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Limiting Reactants Using Mass

Calculate the mass of water produced when

8.00 g H2 and 24.0 g O2 react?

2H2(g) + O2(g) 2H2O(l)

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Limiting Reactants Using Mass

Calculate the grams of H2 for each reactant.H2: 8.00 g H2 x 1 mol H2 x 2 mol H2O x 18.02 g H2O

2.016 g H2 2 mol H2 1 mol H2O= 71.5 g H2O (not possible)

O2: 24.0 g O2 x 1 mol O2 x 2 mol H2O x 18.02 g H2O

32.00 g O2 1 mol O2 1 mol H2O= 27.0 g H2O (smaller)O2 is the limiting reactant.

QUIZ #31) The limiting reactant is…

A. the reactant that produces the least productB. the reactant that produces the most productC. the product that produces the least reactantD. the product that produces the most reactant

2) Given the following balanced equation below, what is the limiting reactant when 3 moles of KO2 reacts with 3 moles of H2O?

4 KO2 + 2 H2O 4 KOH + 3 O2

MUST SHOW WORK!!!