Conservation of Mass

Name:

Date:

Chemical reaction with balanced scales showing mass conservation

📚 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 is neither created nor destroyed during chemical reactions

Mass can appear and disappear randomly

2. In a closed system, when 50g of reactants undergo a chemical reaction, the mass of products will be:

Less than 50g

Exactly 50g

More than 50g

It depends on the reaction

3. Which of the following are examples of closed systems? (Select all that apply)

A sealed zip-lock bag with reactants

An open beaker on a bench

A balloon tied shut after adding reactants

A test tube with a cork stopper

4. During a chemical reaction, atoms are:

Created and destroyed

Rearranged to form new substances

Converted into energy

Multiplied in number

🔬 Part 2: Experimental Investigation

5. You are investigating the reaction between baking soda and vinegar in a sealed bag. Complete the data table below:

Hypothesis: The total mass will _____________ during the chemical reaction because _________________________.

6. Record your experimental observations:

Mass of sealed bag + reactants before reaction: _______ g

Mass of sealed bag + products after reaction: _______ g

Difference in mass: _______ g

7. Explain your results using the Law of Conservation of Mass:

8. What would happen to the mass if the reaction occurred in an open container? Explain why.

⚖️ Part 3: Application and Analysis

9. Balance the following word equation and explain how it demonstrates conservation of mass:

Magnesium + Hydrochloric acid → Magnesium chloride + Hydrogen gas

10. A student burns a piece of paper and notices the ash weighs less than the original paper. Does this violate the Law of Conservation of Mass? Explain your reasoning.

11. Extension Challenge: Research and describe one real-world application where understanding conservation of mass is crucial (e.g., chemical manufacturing, environmental science, or forensics).

12. Draw a simple diagram showing atoms before and after a chemical reaction to illustrate conservation of mass: