Science worksheet explaining the Law of Conservation of Mass using a balance scale to show that the mass of a toolbox remains the same whether closed or open.

The image presents a worksheet about the Law of Conservation of Mass, and it includes a diagram with a balance scale showing two sides: one with a sealed container (like a flask) weighing 48 g, and the other side with a beaker containing various substances (like chemicals or food), also weighing 48 g. The total mass on both sides is 98 g.

Let’s break down and solve the task step by step:

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🔹 Understanding the Law of Conservation of Mass

This law states that:
> Mass cannot be created or destroyed in a chemical reaction.

So, in a closed system:
- Matter can be rearranged or transformed.
- But the total mass remains constant before and after a reaction.

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🔹 Fill in the Blanks (from the worksheet):

> "The law of conservation of mass says…"
> - You cannot create matter.
> - You cannot destroy matter.
> - You can change matter into a new form.
> - The new form will have the same amount of mass as the old form.

✔ These are correct based on the law.

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🔹 Analyzing the Diagram

We see:
- A sealed flask on one side of the balance → 48 g
- A beaker with contents (possibly reactants) → 48 g
- Together, they balance at 98 g

But note: The caption says:
> *"The mass of the flask and its contents is 48 grams."*
> *"The mass of each individual food (including the flask) adds up to 48 grams."*

Wait — this wording seems a bit confusing. Let's clarify.

Actually, the key idea is:
- The flask + contents = 48 g
- The beaker + contents = 48 g
- So total mass on scale = 48 + 48 = 96 g?

But the scale shows 98 g — so there might be a typo or mislabeling.

Alternatively, perhaps:
- The left side: flask + contents = 48 g
- The right side: beaker + contents = 48 g
- Total = 96 g

But the scale reads 98 g — maybe the scale shows the sum of both sides?

Wait — no, the scale has two pans. If each pan has 48 g, then the scale balances, and the total is 96 g.

But the text says: *"The mass of each individual food (including the flask) adds up to 48 grams."* That suggests:
- Flask + contents = 48 g
- Beaker + contents = 48 g
- So total mass = 96 g

Yet the scale shows 98 g — discrepancy?

Wait — actually, look closely: the scale shows "98 g" on each side?

No — the scale has:
- Left pan: 48 g
- Right pan: 48 g
- And the scale itself is balanced.

But the number 98 g appears above the scale — possibly indicating the total mass?

But 48 + 48 = 96, not 98.

Possibility: It's a typo.

Alternatively, maybe the flask + contents = 48 g, and the beaker + contents = 50 g? But it says both are 48 g.

Wait — re-read carefully:

> "The mass of the flask and its contents is 48 grams."
> "The mass of each individual food (including the flask) adds up to 48 grams."

That second sentence is awkwardly worded.

It probably means:
- The flask + contents = 48 g
- The beaker + contents = 48 g
- So total mass = 96 g

But the scale shows 98 g — likely a mistake in the image or labeling.

Alternatively, perhaps the scale reads 98 g because the total mass being measured is 98 g — but that would mean one side is 48 g, the other is 50 g?

But the diagram clearly labels both sides as 48 g.

So unless the scale is showing the combined total, which is 96 g, but written as 98 g, there’s an inconsistency.

But let's assume it's a typo and proceed.

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✔ Conclusion: What does this demonstrate?

Even if there's a minor labeling issue, the key point is:

➡️ The mass before a reaction (in the flask) = 48 g
➡️ The mass after (if the contents react, but in a closed system) should still be 48 g

So, mass is conserved.

If the reaction happens inside the sealed flask, no matter escapes, so:
- The total mass remains unchanged.

Thus, the law of conservation of mass is demonstrated.

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🟩 Final Answer & Explanation:

> The law of conservation of mass says:
> - You cannot create matter.
> - You cannot destroy matter.
> - You can change matter into a new form.
> - The new form will have the same amount of mass as the old form.

✔ This is demonstrated in the diagram:
- The flask and its contents have a mass of 48 g.
- Even if a chemical reaction occurs inside the sealed flask, the total mass stays 48 g.
- The scale balances, showing mass is conserved.

💡 Important: The system must be closed (no gas escaping) for mass to remain constant. In open systems, gases may escape, making it seem like mass is lost — but in reality, it's just not measured.

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✔ Summary:

- The law of conservation of mass holds true.
- The mass before and after a reaction remains the same in a closed system.
- The diagram illustrates this with a balanced scale.
- Any discrepancy in numbers (e.g., 98 g vs. 96 g) is likely a typo or error in labeling.

Let me know if you'd like a corrected version of the worksheet!