1. Chapter 5 Chemical Reactions

2. The Mole

3. 1 dozen eggs = 12 eggs
1 Gross pencils = 144 pencils
1 Ream of paper = 500 sheets of paper

4. The Mole 1 mole = 6.022 x 1023 things Avogadro’s number
The number of carbon atoms in 12g of C-12
Abbreviation: “mol”
How much does this weigh?

5. 1 mole C atoms = 6.022 x 1023 Carbon atoms
6.022 x 1023 Carbon atoms = 1 mole of carbon atoms
1 mole bicycles = x 1023 bicycles
6.022 x 1023 bicycles = 1 mole of bicycles
1 mole of anything = x 1023 items of anything
6.022 x 1023 items of anything = 1 mole of anything

6. Cu, Al, Pb, S, Mg, Cr

7. Mole and Mass Relationships
carbon
12.01 g
1 mole
sulfur
32.06 g

8. Molar Mass The mass, in grams, of one mole of any element or compound
Abbreviated with capital, italicized M
Unit = grams/mole = g/mol
Also called Formula Mass and Formula Weight

9. Problems
You need mol Cu for an experiment, how many grams should you use? How many atoms of Cu is this?
You have g Hg. How many moles are present?

10. Write the molecular formula or formula unit for the compounds above.
Cl-
Na+
Cl-
Na+
Cl-
Na+
Cl-
Na+
Write the molecular formula or formula unit for the compounds above.
What are the molecular and formula weights for the compounds above?

11. What is the mass of 1. 34 mole of the first compound
What is the mass of 1.34 mole of the first compound? What is the mass of carbon in this sample?
How many moles of Sodium Chloride are present in 9.29 g? How many moles of sodium are present in the sample?

12. How many oxygen atoms are there in 5.62g of Carbon Dioxide?

13. Your nurse gives you 10. 0g morphine, C17H19NO3 , for pain
Your nurse gives you 10.0g morphine, C17H19NO3 , for pain. How many moles is this? How many grams of oxygen are present in this dose of analgesic?

14. Chemical Equations H2 (g) + Cl2(g)  2 HCl (g) Reactants Product(s)
Coefficient
Physical State
Subscript
H2 (g) + Cl2(g)  2 HCl (g)
Reactants
Product(s)

15. Law of Conservation of Matter/Mass
Matter is neither created, nor destroyed, but is merely rearranged
The mass of the reactants must equal the mass of the products
H2 (g) + Cl2(g)  2 HCl (g)

16. Balancing Chemical Equations
Zn(s) + HCl(aq)  H2(g) + ZnCl2(aq)
Write the unbalanced equation
Balance the atoms of one element
Choose another element and balance it
Continue until all elements have the same number of atoms on both sides of the equation
Check yourself

17. 5.2 Balancing Chemical Equations
HOW TO Balance a Chemical Equation
Write a balanced chemical equation for
the reaction of propane (C3H8) with
oxygen (O2) to form carbon dioxide (CO2)
and water (H2O).
Example
Step [1]
Write the equation with the correct formulas.
C3H O2
CO H2O
The subscripts in a formula can never be changed to balance an equation, because changing a subscript changes the identity of a compound.

18. 5.2 Balancing Chemical Equations
HOW TO Balance a Chemical Equation
Balance the equation with coefficients one
element at a time.
Step [2]
Balance the C’s first:
Balance the H’s next:

19. 5.2 Balancing Chemical Equations
HOW TO Balance a Chemical Equation
Balance the equation with coefficients one
element at a time.
Step [2]
Finally, balance the O’s:

20. 5.2 Balancing Chemical Equations
HOW TO Balance a Chemical Equation
Balance the equation with coefficients one
element at a time.
Step [2]
Finally, balance the O’s:

21. 5.2 Balancing Chemical Equations
HOW TO Balance a Chemical Equation
Check to make sure that the smallest set
of whole numbers is used.
Step [3]

22. Problems __ N2(g) + __ H2(g)  __ NH3(g)
__ Fe(s) + __ Cl2(g)  __ FeCl3(s)
__NH3(g) + __O2(g)  __NO(g) + __H2O(g)
__C5H12(l) + __O2(g)  __CO2(g) + __H2O(g)

23. 5.3 Types of Reactions
The majority of chemical reactions fall into 6 categories:
combination
decomposition
single replacement
double replacement
oxidation and reduction (Section 5.4)
acid-base (Chapter 9)