Rubric: Explanation about Chemical Reaction Problem

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Quantitative Results:

1.Claim
1
Vague statement, like “might have
2
Vague statement, like “might have happened"
3
Explicitly states “A chemical reaction occurred"
2.Evidence
1
Provides inappropriate data, like "the volume is the same” or provides vague evidence, like “the data table is my evidence.”
2
Provides 1 or 2 of the following pieces of evidence: the densities and melting points of Layers A and B are different from the densities and melting points of either butanic acid or butanol. Layer A is insoluble in water while both butanol and butanic acid are soluble in water. May also include inappropriate evidence, like references to volume or mass.
3
Provides all 3 of the following pieces of evidence: the densities and melting points of Layers A and B are different from the densities and melting points of either butanic acid or butanol. Layer A is insoluble in water while both butanol and butanic acid are soluble in water.
3.Reasoning
1
Provides an inappropriate reasoning statement like “they are like the fat and soap we used in class” or does not provide any reasoning.
2
Repeats the evidence about densities, melting points, and/or solubility. Or provides an incomplete generalization about properties, like “volume is not a property so it does not count.”
3
Includes a complete generalization that density, melting point, and solubility are all properties. Different substances have different properties. When a chemical reaction occurs, new substances are formed as products of the reaction. These new substances will have properties different from those of the original substances. Since layers A and B have properties different from either Layer A or Layer B, these layers must contain new substances indicating that a chemical reaction must have occurred.