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Unexpected Precipitation—A Discrepant Chemical Demonstration Kit

By: The Flinn Staff

Item #: AP6651

Price: $13.40

In Stock.

The Unexpected Precipitation Chemical Demonstration Kit exposes the opposite of what is typically observed in precipitation reactions. This “discrepant demonstration” is great for teaching there are exceptions to many rules in chemistry.

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This item can only be shipped to schools, museums and science centers

Product Details

A precipitate forms as a solution is heated, and dissolves again as it cools—opposite of what is typically observed in precipitation reactions. This “discrepant demonstration” is great for introducing the idea that there are exceptions to many rules in chemistry! The solution may be reused many times.

Concepts: Exceptions to chemical rules, precipitation, saturation, solubility.
Time Required: 15 minutes


Materials Included in Kit: 
Calcium acetate solution, saturated, 500 mL

Correlation to Next Generation Science Standards (NGSS)

Science & Engineering Practices

Asking questions and defining problems
Planning and carrying out investigations
Analyzing and interpreting data
Obtaining, evaluation, and communicating information

Disciplinary Core Ideas

MS-PS1.A: Structure and Properties of Matter
MS-PS1.B: Chemical Reactions
HS-PS1.B: Chemical Reactions
HS-PS2.B: Types of Interactions

Crosscutting Concepts

Structure and function

Performance Expectations

MS-PS1-1: Develop models to describe the atomic composition of simple molecules and extended structures.
MS-PS1-2: Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
HS-PS1-1: Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms.
HS-PS1-3: Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles.
HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.
MS-ESS2-5: Collect data to provide evidence for how the motions and complex interactions of air masses results in changes in weather conditions.