Unpacked Content
Scientific and Engineering Practices
Planning and Carrying out Investigations
Crosscutting Concepts
Patterns
Knowledge
Students know:
- A substance is matter which has a specific composition and specific properties.
- Every pure element is a substance. Every pure compound is a substance.
- Pure substances have characteristic properties.
- Characteristic properties are physical or chemical properties that are not affected by the amount or shape of a substance.
- Characteristic properties can be used to identify a pure substance.
- Physical properties of a substance are characteristics that can be observed without altering the identity (chemical nature) of the substance.
- Color, odor, density, melting temperature, boiling temperature, and solubility are examples of physical properties.
- Chemical properties of a substance are characteristics that can be observed but alter the identity (chemical nature) of the substance.
- Flammability, reactivity with water, and pH are examples of chemical properties.
Skills
Students are able to:
- Identify the phenomena under investigation, which includes pure substances and their characteristic properties.
- Identify the purpose of the investigation, which includes demonstrating that one pure substance can be distinguished from another based on characteristic properties.
- Develop a plan for the investigation individually or collaboratively.
- Describe factors used in the investigation including appropriate units (if necessary), independent and dependent variables, controls and number of trials for each experimental condition.
- Perform the investigation as prescribed by the plan.
- Make a claim, to be supported by evidence, to support or refute an explanation or model for a given phenomenon, including the idea that one pure substance can be distinguished from another based on characteristic properties.
- Identify evidence to support the claim from the given materials.
- Evaluate the evidence for its necessity and sufficiency for supporting the claim.
- Use reasoning to connect the evidence and evaluation to the claim that one pure substance can be distinguished from another based on characteristic properties.
Understanding
Students understand that:
- Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it.
- Pure substances can be distinguished from other pure substances based on characteristic properties.
- Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants.
Vocabulary
- Investigation
- Claims
- Evidence
- Substance
- Matter
- Composition
- Property
- Element
- Compound
- Pure substance
- Characteristic properties
- Physical property (includes, but not limited to, color, odor, density, melting point, boiling point, solubility)
- Chemical property (includes, but not limited to, flammability, reactivity with water, pH)
