Chapter 21 review

Solve the problem: Al + O2 --> Al2O3

• 4Al + 3O2 --> 2Al2O3
• 2Al + 4O2 --> Al2O3

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

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

Name this reaction, Cl₂ + 2KI _-->  I₂ + 2KCl

• Synthesis
• Single Replacement
• Double Replacement
• Decomposition

_{Name this reaction, CO2} + H₂O --> H₂CO₃ 

• Decomposition
• Single Replacement
• Synthesis
• Combustion

How many atoms of carbon (C) are in C₆H₁₂O₆?

• 3
• 6
• 12
• 24

How many Al atoms are in this compound?         4Al₂O₃

• 2
• 8
• 6
• 4

___________________ are the elements are compounds that leave (are formed in) a chemical
reaction.

• Polymers
• Bonds
• Reactants
• Products

  In a Chemical Reaction, the Law of Conservation of Mass states? 

• Matter is never created but sometimes destroyed
• Matter is NOT created or destroyed.
• Matter is created and destroyed. 
• Matter is sometimes created but never destroyed

Solid magnesium, Mg, reacts with oxygen gas, O₂, to form the solid magnesium oxide, MgO. Which equation is a balanced chemical equation for this chemical change? 

• 2Mg + O₂ → 2MgO
• Mg + 2O → 2MgO
• Mg + O₂ → MgO₂
• Mg + O → MgO

 Which is NOT an example of chemical change?

• production of gas.
• change in color.
• change in size.
• transfer of energy.