Rubric: Explanation about Chemical Reaction Problem
1Vague statement, like “might have
2Vague statement, like “might have happened"
3Explicitly states “A chemical reaction occurred"
1Provides inappropriate data, like "the volume is the same” or provides vague evidence, like “the data table is my evidence.”
2Provides 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.
3Provides 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.
1Provides an inappropriate reasoning statement like “they are like the fat and soap we used in class” or does not provide any reasoning.
2Repeats 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.”
3Includes 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.