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Melting Results and Molecular Modeling

The students learn about melting point using sugar and salt. Special guest Dr. Ludovice discusses molecular modeling.

The students learn about melting point using sugar and salt. Special guest Dr. Ludovice discusses molecular modeling.

Premiere Date: July 11, 2016 | Runtime: 00:18:47

Support Materials

Toolkit

Unit 4F Note Taking Guide & Segment Questions
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Crosscutting Concepts

System and System Models

Defining the system under study—specifying its boundaries and making explicit a model of that system—provides tools for understanding and testing ideas that are applicable throughout science and engineering.

Scale, Proportion, and Quantity

In considering phenomena, it is critical to recognize what is relevant at different measures of size, time, and energy and to recognize how changes in scale, proportion, or quantity affect a system’s structure or performance.

Stability and Change

For natural and built systems alike, conditions of stability and determinants of rates of change or evolution of a system are critical elements of study.

Structure and Function

The way in which an object or living thing is shaped and its substructure determine many of its properties and functions.

Science & Engineering Practices

Analyzing and Interpreting Data

Once collected, data must be presented in a form that can reveal any patterns and relationships and that allows results to be communicated to others. Because raw data as such have little meaning, a major practice of scientists is to organize and interpret data through tabulating, graphing, or statistical analysis. Such analysis can bring out the meaning of data—and their relevance—so that they may be used as evidence.
Engineers, too, make decisions based on evidence that a given design will work; they rarely rely on trial and error. Engineers often analyze a design by creating a model or prototype and collecting extensive data on how it performs, including under extreme conditions. Analysis of this kind of data not only informs design decisions and enables the prediction or assessment of performance but also helps define or clarify problems, determine economic feasibility, evaluate alternatives, and investigate failures. (NRC Framework, 2012, p. 61-62)

Vocabulary

adhesion - the tendency of molecules to stick to substances that are dissimilar. 

anion - a negatively charged ion. 

cation - a positively charged ion. 

chemical bond - an electrical interaction between the positively charged nuclei and the negatively charged electrons of atoms that forms when the force of attraction is stronger than the force of repulsion. 

cohesion - the action or property of like molecules sticking together, being mutually attractive. 

covalent bond - a bond in which pairs of electrons are shared between atoms, instead of being transferred from one atom to another. 

double covalent bond - a bond in which atoms share two pairs of electrons. 

electronegativity - the ability of an atom to attract additional electrons. 

electrostatic force - a force in which oppositely charged particles are attracted to each other, while like charges repel each other.

intermolecular forces - the attractive forces acting between molecules.

intramolecular bond - a bond that is occuring within a molecule. 

ion - an atom with a positive or negative charge. 

ionic bond - a bond that occurs between atoms, through the transfer of electrons, when a positively charged atom and negatively charged atom are attracted to one another. 

molecule - a group of atoms that have chemically bonded and behave as an individual unit. 

nonpolar covalent bond - a bond that forms between atoms in which their electrons are shared equally. 

octet rule - when an ion or an atom has eight valence electrons, it is at its most stable electron configuration.

polar covalent bond - a bond in which electrons are shared unequally between atoms. 

single covalent bond - a bond in which atoms share only one pair of electrons. 

triple covalent bond - A bond in which atoms share three pairs of electrons. 

valence electrons - the electrons found in the outermost electron shell of an atom. 

Georgia Standards of Excellence

SC2Obtain, evaluate, and communicate information about the chemical and physical properties of matter resulting from the ability of atoms to form bonds.

SC2.aPlan and carry out an investigation to gather evidence to compare the physical and chemical properties at the macroscopic scale to infer the strength of intermolecular and intramolecular forces.

SC2.bConstruct an argument by applying principles of inter- and intra- molecular forces to identify substances based on chemical and physical properties.

SC2.cConstruct an explanation about the importance of molecular-level structure in the functioning of designed materials. (Clarification statement: Examples could include why electrically conductive materials are often made of metal, flexible but durable materials are made up of long chained molecules, and pharmaceuticals are designed to interact with specific receptors.)

SC2.dDevelop and use models to evaluate bonding configurations from nonpolar covalent to ionic bonding. (Clarification statement: VSEPR theory is not addressed in this element.)

SPS2Obtain, evaluate, and communicate information to explain how atoms bond to form stable compounds.

SPS2.aAnalyze and interpret data to predict properties of ionic and covalent compounds. (Clarification statement: Properties are limited to types of bonds formed, elemental composition, melting point, boiling point, and conductivity.)

Request Teacher Toolkit

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