Mass Stays the Same - Middle School Physical Science
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What does it mean to say atoms are conserved in a chemical reaction model?
What does it mean to say atoms are conserved in a chemical reaction model?
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Atoms are not created or destroyed; they are rearranged. Chemical reactions only reorganize existing atoms.
Atoms are not created or destroyed; they are rearranged. Chemical reactions only reorganize existing atoms.
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Which option best explains why mass can appear to increase in an open-system reaction?
Which option best explains why mass can appear to increase in an open-system reaction?
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A gas from the air enters and becomes part of the products. Gained mass indicates matter entered the system.
A gas from the air enters and becomes part of the products. Gained mass indicates matter entered the system.
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Which option is the correct interpretation of particle models for a closed system reaction?
Which option is the correct interpretation of particle models for a closed system reaction?
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Particles rearrange; the total number of atoms stays the same. Atoms only change bonds, not quantity.
Particles rearrange; the total number of atoms stays the same. Atoms only change bonds, not quantity.
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Which option best explains why mass can appear to decrease in an open-system reaction?
Which option best explains why mass can appear to decrease in an open-system reaction?
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A gas product escapes to the surroundings. Lost mass indicates matter left the system.
A gas product escapes to the surroundings. Lost mass indicates matter left the system.
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Which measurement best tests mass conservation in a closed-system lab model?
Which measurement best tests mass conservation in a closed-system lab model?
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Total mass of the sealed container and contents before and after. Comparing total mass verifies conservation.
Total mass of the sealed container and contents before and after. Comparing total mass verifies conservation.
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What is a closed system in the context of conserving mass?
What is a closed system in the context of conserving mass?
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A system where no matter enters or leaves the boundary. Matter cannot cross the boundary, keeping total mass constant.
A system where no matter enters or leaves the boundary. Matter cannot cross the boundary, keeping total mass constant.
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What is an open system in the context of conserving mass?
What is an open system in the context of conserving mass?
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A system where matter can enter or leave the boundary. Matter can cross the boundary, allowing mass changes.
A system where matter can enter or leave the boundary. Matter can cross the boundary, allowing mass changes.
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Identify the key evidence in a balance-scale model that shows mass is conserved.
Identify the key evidence in a balance-scale model that shows mass is conserved.
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The scale stays balanced before and after the change. Equal mass on both sides keeps the balance level.
The scale stays balanced before and after the change. Equal mass on both sides keeps the balance level.
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Find the missing value using $m_{reactants} = m_{products}$: products total $= 120,g$, one reactant $= 45,g$.
Find the missing value using $m_{reactants} = m_{products}$: products total $= 120,g$, one reactant $= 45,g$.
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$75,g$. $120,g - 45,g = 75,g$ for the other reactant.
$75,g$. $120,g - 45,g = 75,g$ for the other reactant.
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What is the correct conclusion if a sealed container has the same mass before and after heating?
What is the correct conclusion if a sealed container has the same mass before and after heating?
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Mass remained constant because the system was closed. No matter escaped, so mass stayed constant.
Mass remained constant because the system was closed. No matter escaped, so mass stayed constant.
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Which option is the correct justification from a model when a precipitate forms in a sealed bag?
Which option is the correct justification from a model when a precipitate forms in a sealed bag?
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Total mass stays the same; particles changed arrangement, not amount. Sealed bag = closed system, so mass is conserved.
Total mass stays the same; particles changed arrangement, not amount. Sealed bag = closed system, so mass is conserved.
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What must be counted in a particle model to justify mass conservation during a reaction?
What must be counted in a particle model to justify mass conservation during a reaction?
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The number of each type of atom on both sides. Equal atom counts prove mass conservation.
The number of each type of atom on both sides. Equal atom counts prove mass conservation.
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Identify the correct claim if a model shows the same atoms before and after but grouped differently.
Identify the correct claim if a model shows the same atoms before and after but grouped differently.
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Mass is conserved because the atoms are only rearranged. Same atoms = same total mass, just reorganized.
Mass is conserved because the atoms are only rearranged. Same atoms = same total mass, just reorganized.
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Identify the correct conclusion if a model shows atoms leaving the boundary during a reaction.
Identify the correct conclusion if a model shows atoms leaving the boundary during a reaction.
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The system is open, so measured mass of the system can change. Matter leaving means it's not truly closed.
The system is open, so measured mass of the system can change. Matter leaving means it's not truly closed.
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Which statement best completes the claim: In a closed system, the mass of reactants ___ the mass of products?
Which statement best completes the claim: In a closed system, the mass of reactants ___ the mass of products?
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equals. Mass is conserved, so reactant mass = product mass.
equals. Mass is conserved, so reactant mass = product mass.
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Which boundary feature in a diagram indicates a closed system?
Which boundary feature in a diagram indicates a closed system?
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A sealed boundary with no arrows showing matter exchange. No arrows indicate no matter exchange with surroundings.
A sealed boundary with no arrows showing matter exchange. No arrows indicate no matter exchange with surroundings.
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What is the equation that represents conservation of mass in a closed system?
What is the equation that represents conservation of mass in a closed system?
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$m_{reactants} = m_{products}$. Mathematical representation of mass conservation.
$m_{reactants} = m_{products}$. Mathematical representation of mass conservation.
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Find the missing value using $m_{reactants} = m_{products}$: reactants $= 50,g$, one product $= 18,g$.
Find the missing value using $m_{reactants} = m_{products}$: reactants $= 50,g$, one product $= 18,g$.
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$32,g$. $50,g - 18,g = 32,g$ for the other product.
$32,g$. $50,g - 18,g = 32,g$ for the other product.
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What law states that total mass stays constant in a closed system during a reaction?
What law states that total mass stays constant in a closed system during a reaction?
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Law of Conservation of Mass. Matter cannot be created or destroyed in chemical reactions.
Law of Conservation of Mass. Matter cannot be created or destroyed in chemical reactions.
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Find and correct the claim: "Mass is conserved because the number of molecules stays the same."
Find and correct the claim: "Mass is conserved because the number of molecules stays the same."
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Correct: mass is conserved because the number of atoms stays the same. Molecules can change, but atom count must stay constant.
Correct: mass is conserved because the number of atoms stays the same. Molecules can change, but atom count must stay constant.
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What is the law that states mass is conserved in a closed system?
What is the law that states mass is conserved in a closed system?
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Law of Conservation of Mass. This fundamental law states matter cannot be created or destroyed.
Law of Conservation of Mass. This fundamental law states matter cannot be created or destroyed.
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Which statement best describes mass during a chemical reaction in a closed system?
Which statement best describes mass during a chemical reaction in a closed system?
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Total mass of reactants equals total mass of products. Mass is conserved because atoms only rearrange, not disappear.
Total mass of reactants equals total mass of products. Mass is conserved because atoms only rearrange, not disappear.
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What is the main difference between an open system and a closed system for mass evidence?
What is the main difference between an open system and a closed system for mass evidence?
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Open: matter can leave or enter; closed: matter cannot. The key distinction is whether matter can cross system boundaries.
Open: matter can leave or enter; closed: matter cannot. The key distinction is whether matter can cross system boundaries.
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Which measurement provides direct evidence for mass conservation in a closed-container reaction?
Which measurement provides direct evidence for mass conservation in a closed-container reaction?
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Same total mass before and after the reaction. Equal mass measurements prove no matter was created or destroyed.
Same total mass before and after the reaction. Equal mass measurements prove no matter was created or destroyed.
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Identify the key model-based idea that explains why mass stays constant in a closed system.
Identify the key model-based idea that explains why mass stays constant in a closed system.
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Atoms are rearranged, not created or destroyed. Chemical reactions only reorganize existing atoms into new molecules.
Atoms are rearranged, not created or destroyed. Chemical reactions only reorganize existing atoms into new molecules.
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