To determine which response best models how a chemical reaction follows the conservation of mass law, we need to remember that the law of conservation of mass states that mass in an isolated system is neither created nor destroyed. In a chemical reaction, the number and type of atoms in the reactants must equal the number and type of atoms in the products.
Let's analyze each option:
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First response: A large black circle with 2 small light circles reacts with a large black circle to produce a molecule made up of 2 large black circles with 1 small white circle attached.
- Reactants: 2 large black circles + 2 small light circles.
- Products: 2 large black circles + 1 small white circle.
- There's a change in number of small circles and no conservation of mass.
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Second response: A large black circle with 1 small light circle reacts with another identical molecule to produce a molecule made up of 1 large black circle with 1 small white circle attached.
- Reactants: 2 large black circles + 2 small light circles.
- Products: 1 large black circle + 1 small white circle – there’s a reduction in total mass.
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Third response: A large black circle with 2 small light circles reacts with another identical molecule to produce a molecule made up of 2 large black circles with 4 small white circles attached.
- Reactants: 2 large black circles + 4 small light circles.
- Products: 2 large black circles + 4 small white circles.
- This maintains the same number and types of atoms before and after the reaction.
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Fourth response: A large black circle with 1 small light circle reacts with another identical molecule to produce a molecule made up of 1 large black circle with 2 small white circles attached.
- Reactants: 2 large black circles + 2 small light circles.
- Products: 1 large black circle + 2 small white circles.
- This also shows a reduction in total mass.
Based on this analysis, the option that best illustrates the conservation of mass is the third response since the number and types of circles (atoms) on both sides of the equation are equivalent. Thus, the third response follows the conservation of mass law correctly.
1 answer