📚 Part 1: Understanding Conservation of Mass

1. The Law of Conservation of Mass states that:

Mass is created during chemical reactions

Mass is destroyed during chemical reactions

Mass remains constant in a closed system during chemical reactions

Mass can be converted to energy

2. In a chemical reaction, atoms are:

Created and destroyed

Rearranged but not created or destroyed

Only created

Only destroyed

3. Which of the following could explain why mass appears to be lost in a chemical reaction? (Select all that apply)

Gas escapes from an open container

The reaction occurs in a closed system

Measurement errors with the balance

Water vapour escapes during heating

4. A student mixes 5.0g of baking soda with 10.0g of vinegar in a sealed bag. According to the Law of Conservation of Mass, the total mass after the reaction should be:

Less than 15.0g

Exactly 15.0g

More than 15.0g

Cannot be determined

🔬 Part 2: Practical Investigation Analysis

5. Complete the data table from your vinegar and baking soda experiment:

Initial mass of baking soda: _________ g

Initial mass of vinegar: _________ g

Total initial mass: _________ g

Final mass of sealed bag and contents: _________ g

Difference in mass: _________ g

6. Explain what you observed during the reaction and how it demonstrates the Law of Conservation of Mass:

7. Why was it important to seal the bag during the experiment?

8. Extension: If this same reaction was carried out in an open beaker instead of a sealed bag, predict what would happen to the measured mass and explain why:

⚖️ Part 3: Real-World Applications

9. A piece of magnesium ribbon with a mass of 2.4g is burned in air. The white powder (magnesium oxide) produced has a mass of 4.0g. Explain how this result supports the Law of Conservation of Mass:

10. Fill in the blanks: In industrial chemical processes, understanding conservation of mass is important because it allows chemists to _____________ the amount of products that will be formed and ensures that _____________ are not wasted.

11. Challenge Question: In a combustion reaction, 12g of carbon reacts with 32g of oxygen to form carbon dioxide. Calculate the mass of carbon dioxide produced and explain your reasoning:

Show your working:

Answer: _________ g of carbon dioxide

Explanation: