A. Read Pp. 631-635 and Answer the Following Questions

Chemistry Name : Worksheet : Ch. 20-21 ; Obj. 1-5 Date :

A. Read pp. 631-635 and answer the following questions.

1. ______reactions are chemical reactions in which electrons are transferred between reactants.

2. ______reactions are another name for the above reaction.

3. Put a check next to the following reactions which are redox reactions.(Hint : Ions must be formed as electrons are transferred. Redox reactions are not just the simple combining of already existing ions).

3+ - _____ Fe + 3 Cl -----> FeCl3 _____ S + O2 ------> SO2 _____ Cl2 + H2 -----> 2 HCl 4+ 2- _____ Pb + 2 O ------> PbO2

4. Give two common examples of oxidation reactions which we might observe in our lives..

5. Match the characteristics of the process of oxidation and reduction.

a. oxidation b. reduction

_____ the gaining of electrons in an ionic reaction

_____ the loss of electrons in an ionic reaction

_____ the gaining of oxygen

_____ the loss of oxygen

_____ the loss of a hydrogen atom by a covalent compound

_____ the gaining of a hydrogen atom by a covalent compound

_____ causes an increase charge on an ion (more positive or less negative)

_____ causes a decrease in the charge on an ion (less positive or more negative)

_____ occurs when a magnesium atom becomes a magnesium ion with a 2+ charge.

_____ occurs when sulfur atom becomes a sulfide ion (2- charge).

_____ occurs when electrons shift toward an atom with a higher electronegativity in a covalent bond

_____ occurs when electrons shift away from an atom with a lower electronegativity in a covalent bond 6. _____(T/F) Reduction reactions and oxidation reactions seldom occur together. 7. ______are substances in redox reactions which donate (lose) electrons.

8. ______are substances in redox reactions which accept (gain) electrons.

9. _____ (T/F) The reactant reduced in a redox reaction is also the reactant which is the oxidizing agent.

10. _____ (T/F) The reactant which is oxidized in a redox reaction is also the reducing agent.

11. Identify the reactants which are reduced and the reactant which is oxidized and which reactant is the reducing agent and which reactant is the oxidizing agent in each reaction below.

a. 2K + F2  2KF

_____ oxidized reactant

_____ reduced reactant

_____ reducing agent(reactant)

_____ oxidizing agent (reactant)

b. 4 Al + 3O2  2 Al2O3

c. Mg + I2  MgI2

d. 2 Al + 3 Cl2  2 AlCl3

_____ reduced reactant _____ reducing agent(reactant) _____ oxidizing agent (reactant)