Chapter 21 Chemical Reactions

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

• Decomposition
• Combustion
• Synthesis
• Single Replacement 

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

• Decomposition
• Combustion
• Synthesis
• Single Replacement 

What is a coefficient?

• The small number on the right of the chemical symbol.
• The large number to the left of a formula.

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
• Matter cannot be created or destroyed
• None of these

What must go in the blank space to balance the equation?
4Fe  +  _O₂  -->  2Fe₂O₃

• 1
• 2
• 3
• 4

A reaction that gives off heat to its surroundings is...

• exothermic
• endothermic
• endergonic
• none of these

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

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

In a chemical reaction

• The atoms of the reactants always stay together to form the products
• The atoms of the reactants unbond, rearrange, and then rebond to form the products
• New atoms are formed which combine to make the products
• Some atoms disappear while others multiply to form the products

Which of the following options correctly balances the equation below?
__HNO₂ + __O₂ --> __HNO₃

• 4, 1, 4
• 1, 2, 1
• 1, 2, 1
• 2, 1, 2