Chemical Reactions Test

What reaction has the following general formula:

AB --> A + B

• Synthesis

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

When balancing equations, the rule is that you can only add, change, and remove

• Coefficients
• Mass
• Subscripts
• Elements 

Is this chemical equation balanced?
Al + O₂ → 2Al₂O₃

• Yes
• No

Which statement is true:
Mg → Mg²⁺ + 2e^–

• Mg gains 2 electrons
• Mg_²⁺ loses 2 electrons
• Mg loses 1 electron
• Mg loses 2 electrons

What is the oxidation number of nitrogen in N₂?

• -3

• 0

• +4

• -1

Balance this equation ​ (a)   N₂ + ​ (b)   H₂ --> ​ (c)   NH₃

• 1
• 3
• 2

What does the law of conservation of mass state?

• Matter can transform into energy

• Matter can be created and destroyed

• Matter can neither be created nor destroyed

• Only energy can be conserved, not matter

When the switch is closed, which group of letters correctly represents the direction of electron flow?

• A) A → B → C → D

• B) A → F → E → D

• C) D → C → B → A

• D) D → F → E → A

Label these terms.

a

b

c

d

Reduction 1/2 reaction

Anode

Oxidation 1/2 reaction

Cathode

What is the role of the salt bridge in a voltaic cell? (Check all that apply)

• To allow the movement of water molecules between the two half cells

• To allow the movement of electrons between the half cells

• To allow the movement of ions to maintain charge neutrality