Unit 5 Chemical Reactions Review

In the equation,          2Mg + O₂ ---> 2MgO, which are the reactants?

• Mg and O
• MgO
• Mg and MgO
• O and MgO

Balance this equation, Ca + H₂O --> CaO + H₂

• Ca + 2H₂O --> CaO + 2H₂
• 2Ca + H₂O --> CaO + H₂
• Its balanced as it is
• Cannot be balanced

What type of chemical reaction is this one?
Al(OH)₃ --> Al2O3  + H2O

• Decomposition
• Combustion
• Synthesis
• Single Replacement 

What type of chemical reaction is this one?
Ca + MgCl2 --> CaCl2 + Mg

• Decomposition
• Combustion
• Synthesis
• Single Replacement 

What coefficients are needed to correctly balance the equation?
_Bi   +   _O₂   >   _Bi₂O₃

• 3,2,3
• 2,3,2
• 4,3,2
• none of these

Why must chemical equations be balanced?

• So that the equation doesn't explode

• The reaction won't happen until it is balanced

• Based on the Law of Conservation of Matter, matter cannot be created or destroyed.

• Based on the Law of Conservation of Energy, energy cannot be created or destroyed.e

The right side of the equation below is called the

• products
• reactants

What type of reaction is illustrated below?
2HI --> H₂  +  I₂

• synthesis
• decomposition
• single replacement
• double replacement

Which of the following answers will balance the equation below?
__K + __Br₂ --> __KBr

• 2, 1, 1
• 2, 3, 2
• 2, 1, 2
• 1, 2, 3

What type of chemical reaction is this one?
C₂H₂ + O₂ --> CO₂ + H₂O

• Decomposition
• Combustion
• Synthesis
• Single Replacement