Chemical Equations: Identifying and Balancing Reactions

Which of the following is a balanced chemical equation?

• H2 + O2 → H2O

• 2H2 + O2 → 2H2O

• H2 + O2 → 2H2O

• 2H2 + 2O2 → 2H2O

Fill in the blank: In a balanced chemical equation, the number of atoms for each element is the same on both the ______ and the ______.

• A) reactant, product

• B) left, right

• C) start, end

• D) top, bottom

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

• Synthesis

• Decomposition

• Photosynthesis

• Combustion

Fill in the blank: Chemical reactions can be organized into 5 categories, including Synthesis, Decomposition, Single Displacement, Double Displacement, and ________.

• A) Photosynthesis

• B) Combustion

• C) Evaporation

• D) Condensation

What is a synthesis reaction?

• A) A reaction where two or more reactants combine to form a single product.

• B) A reaction where a single reactant breaks down into multiple products.

• C) A reaction where reactants exchange components to form new products.

• D) A reaction where energy is absorbed from the surroundings.

Fill in the blank: In a synthesis reaction, the general formula is A + B → ____.

• A) A + B

• B) AB

• C) A - B

• D) BA

What is a decomposition reaction?

• One reactant breaks down to form two or more products.

• Two reactants combine to form one product.

• A reactant is replaced by another element.

• Two elements combine to form a compound.

Fill in the blank: In a decomposition reaction, 2 H2O decomposes into 2 H2 and ____.

• O2

• CO2

• H2O

• H2

Which type of reaction is represented by the equation: 2 Na + Cl₂ → 2 NaCl?

• Synthesis

• Decomposition

• Single Replacement

• Double Replacement

Fill in the blank: The reaction ZnCO₃ → ZnO + CO₂ is a ________ reaction.

• A) Synthesis

• B) Decomposition