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Determination of the Hardness of Water—Student Laboratory Kit

By: The Flinn Staff

Item #: AP9091

Price: $31.05

With the Determination of the Hardness of Water Consumer Chemistry Laboratory Kit, students learn how to properly use pipets and burets. Students also perform stoichiometric calculations involving volume and molarity.

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Product Details

Titrate metal ions found in tap water using the reagent ethylenediaminetetraacetic acid (EDTA). The end point is found using a dye called Eriochrome Black T (EBT), which also forms complexes with metal ions in solution. Students learn how to properly use pipets and burets and will perform stoichiometric calculations involving volume and molarity. Kit includes reproducible student procedure, complete Teacher Notes with sample data and answers to questions, and all necessary chemicals. Complete for 24 students working in pairs.


Materials Included in Kit: 
Ammonia/ammonium chloride buffer, pH 10, 500 mL
EDTA solution, 0.005 M, 1 L
Eriochrome black T, EBT, 0.15 g

Correlation to Next Generation Science Standards (NGSS)

Science & Engineering Practices

Asking questions and defining problems
Planning and carrying out investigations
Analyzing and interpreting data
Using mathematics and computational thinking

Disciplinary Core Ideas

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

Crosscutting Concepts

Cause and effect
Scale, proportion, and quantity
Systems and system models

Performance Expectations

MS-ETS1-1. Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.
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-PS1-2. Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
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-ETS1-2. Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.