Chemical Reactions Quiz

What is a key difference between chemical and physical changes?

• Chemical changes do not involve energy.

• Physical changes always involve color change.

• Chemical changes alter the composition of matter.

• Physical changes create new substances.

Which of the following is an example of a chemical change?

• Cutting paper

• Melting ice

• Boiling water

• Burning wood

During a chemical reaction, what happens to the bonds between atoms?

• They remain unchanged.

• They are only formed.

• They are only broken.

• They are broken and formed.

What indicates that a chemical reaction has occurred?

• Change in shape

• Emission of light

• Change in texture

• Change in size

What type of reaction involves the combination of elements to form a compound?

• Single replacement

• Synthesis

• Combustion

• Decomposition

In a combustion reaction, what is typically required to initiate the process?

• A spark

• Carbon dioxide

• Nitrogen

• Water

In a chemical equation, what does the arrow represent?

• The number of molecules

• The direction of the reaction

• The type of reaction

• The energy change

What does a subscript in a chemical formula indicate?

• The type of reaction

• The number of molecules

• The number of atoms in a molecule

• The energy level

What principle states that matter cannot be created or destroyed in a chemical reaction?

• Law of Thermodynamics

• Law of Conservation of Energy

• Law of Conservation of Mass

• Law of Chemical Equilibrium

Which type of reaction absorbs energy from its surroundings?

• Combustion

• Exothermic

• Endothermic

• Decomposition