Chemical Reactions

Which of the following is not a sign of a chemical reaction?

• change of energy or heat

• color change

• formation of a precipitate

• change of mass

• change of smell

How many Carbons are in the following formula? CaCO₃

• 3

• 2

• 1

• 0

Which of the following is a balanced equation?

• Na + Cl₂--> NaCl

• C + O₂ --> CO

• 2H₂O--> 2H₂ + O₂

• NaOH + 2HCl --> NaCl + H₂O

Which of the following is a decomposition equation?

• Na + Cl₂--> NaCl

• C + O₂ --> CO

• 2H₂O--> 2H₂ + O₂

• NaOH + 2HCl --> NaCl + H₂O

Which of the following is a double replacement equation?

• Na + Cl₂--> NaCl

• C + O₂ --> CO

• 2H₂O--> 2H₂ + O₂

• NaOH + HCl --> NaCl + H₂O

Which of the following is a single replacement equation?

• Na + Cl₂--> NaCl

• NaBr + Cl₂ --> NaCl + Br₂

• 2H₂O--> 2H₂ + O₂

• NaOH + HCl --> NaCl + H₂O

For a process to be defined as a chemical reaction, _____ must be produced.

• a new substance

• the same substance

• light

• more mass

Which equation indicates a synthesis reaction?

• 2HgO -->2Hg + O2

• CH4 + 2O2 --> CO2 + 2H2O

• Zn + Cu --> Zn + Cu

• 4H2 + 2O2 ---> 4H2O

Which equation indicates a decomposition reaction?

• 2HgO -->2Hg + O2

• CH4 + 2O2 --> CO2 + 2H2O

• Zn + Cu --> Zn + Cu

• 4H2 + 2O2 ---> 4H2O

Which equation indicates a combustion reaction?

• 2HgO -->2Hg + O2

• CH4 + 2O2 --> CO2 + 2H2O

• Zn + Cu --> Zn + Cu