Physical Science
Module 4: Lesson 1-5
Introduction to Modeling and Chemical
Reactions
Chemistry Concepts
• Physical Properties of matter
Color, melting point, boiling point, density, …
Can you think of other physical Properties?
• Chemical Properties of matter
Why is Gold and diamond expensive?
Why is Hydrogen gas so dangerous?
Why does Peroxide bubble when poured on an wound?
Is solubility in water a physical or chemical property?
Atoms and Periodic Table
Elements are arranged in the Periodic Table according
to their atomic number, which determines their
chemical properties and chemical reactivity.
Chemical Symbols & Ions
Some elements react to give away electrons and
some elements react to gain electrons.
Examples:
Sodium: Na likes to lose an electron to become Na+
Silver: Ag loses an electron  Ag+
Chlorine: Cl gains an electron  ClOxygen: O likes to gain two electrons  O-2
Copper: Cu can lose 1 or 2 electrons  Cu+1 or Cu+2
Aluminum: Al loses 3 electrons to become Al+3
Ionic Compounds
• Ionic Compounds are made of positive ions
(cations) and negative ions (anions) held
tightly together.
• When (inorganic) ionic compounds dissolve in
water, they separate into their positive and
negative ions.
• States of matter: solid, liquid, gas.
• Matter that dissolves in water has Aqueous
state, and we have a solution.
Examples of Ionic Compounds
•
•
•
•
NaCl (Table Salt) in water: Saline solution
AgCl: silver nitrate
CuCl2: Copper Chloride
Al2O3: aluminum Oxide
AgCl (s) in water  AgCl (aq)  Ag+1 (aq) + Cl- (aq)
Video or Live Demonstration
Aqueous Silver Nitrate and solid Copper reaction
Signs of a chemical reaction:
Color change
Formation of gas: bubbles or funny odor
Formation of precipitate
Change of temperature
StarLogo Nova Base Model
• Water Molecules setup
• Silver Nitrate setup
• Copper rod Setup
Why 200 steps?
Would 150 steps be enough?
Running the Model: Simulation
What signs of a chemical reaction do you see in
this simulation?
Assumptions (Abstractions) in this model?
Physical Science
Lesson 2: Modeling Chemical Reactions
Student Activity #1
Analyzing the Model
Use Model Observation Form
Download the StarLogo Nova Base model:
“silver nitrate and copper reaction”
Remix and rename
Run the model and have fun analyzing
Student Activity #2
Use the Student Activity Sheet
• Challenge 1:
Modify the model to add or remove some or all
of the water molecules in the model.
• Challenge 2:
Modify the code to move the copper rod
somewhere else in the solution keeping the
number of agents of copper the same.
Physical Science
Lesson 3: Products of Chemical Reactions
Chemistry Concepts
Observed behavior
Aqueous silver nitrate added to solid copper will react to
form aqueous copper nitrate and solid silver.
Chemical Reaction
2 AgNO3 (aq) + Cu (s)  Cu(NO3)2 (aq) + 2 Ag (s)
Reactants 
Products
• Balancing chemical equations
• Limiting reactant and reactant in excess
Computer Science Concepts
• Agents represented by breeds. Default breed
in StarLogo Nova is “Turtle”. Breeds can be
added and can be renamed.
• What is missing from the model?
Computer Science Concepts
• What is missing from the model?
2 AgNO3 (aq) + Cu (s)  Cu(NO3)2 (aq) + 2 Ag (s)
Reactants 
Products
• Did we capture all of the reactants and
products in our model?
• Does our model accurately represent the
conservation of mass?
Student Activity #1
• Remix and Rename the StarLogo Nova base
model:
“silver nitrate and copper reaction”
• Use Student Activity Sheet for guidelines.
• Challenge: Change the code to add copper
nitrate agents to represent the missing
chemical product from the model.
Student Activity #2: Experiment
• Start with the your modified model.
• Use Experimental Design Form.
Challenge: Run experiment at different initial
quantities of copper or silver nitrate and get
the amount of silver produced.
How much silver is produced in each case?
Which is the limiting reactant and reactant
in excess in each case?
Physical Science
Lesson 4: Complex Ions in Solution
Ions in water
 Silver nitrate, Ag(NO3) in water dissociates to one
ion of Ag+ and one ion of (NO3)- .
Ag(NO3) (s) in water  Ag+ (aq) + NO3- (aq)
 Copper nitrate, Cu(NO3)2, is an ionic compound
that is soluble in water.
In water, it dissociates to Cu+2 [or Cu(II)] and two
(NO3)- ions.
Cu(NO3)2 (aq)  Cu+2 (aq) + 2 (NO3)- (aq)
Complex Ions
 Copper ions [Cu+2 [or Cu(II)] in water form a
complex ion with 3 water molecule which
produces the blue hue in the solution. This
complex can be referred to as
Copper Nitrate.3H2O or Cu(II).3H2O
• Note: NO3- is a complex negative ion but it a
spectator ion in this reaction
Ionic Reaction:
2 Ag+ (aq) + 2 NO3- (aq) + Cu (s) ---> Cu2+ (aq) + 2 NO3- (aq) + 2 Ag (s)
Student Activity #1
Copper nitrate in water forms a complex with 3 water
molecules, turning solution blue.
Challenge: Change the code to create additional breeds
Cu(II).H2O
Cu(II).2H2O
Cu(II).3H2O
 Start with StarLogo Nova modified model from Lesson
3. Remix and Rename.
 Use Student Activity Sheet for guidance.
Execute your model every time you add a piece of code.
Debug if needed. Save often.
Rate of a Reaction
• Increasing the temperature increases the rate
of the reaction because the kinetic energy of
the reactants increases.
• Rate of reaction is determined by how fast the
reactants are used up or products formed over
time.
Physical Science
Lesson 5: Impacts on rate of reaction
Model Abstraction: Mixing
• In the model, we can change the mixing of
ions in solution by altering the Wiggle Walk.
Change the maximum number of degrees
turned in the left and right turn commands.
See the impact of changing how agents move.
Model Abstraction: Kinetic Energy
• In the model, we can change the number of
forward steps from 1 to 2 to 3, to mimic the
kinetic energy of ions and molecules.
Student Activity #2: Experiment
Challenge: Run experiment at different kinetic energy levels
OR different mixing and measure time when half of the
copper is used up.
 Make sure the initial amount of copper and silver nitrate is
the same throughout the experiment.
 Change the number of forward steps from 1 to 2 to 3 for
each experiment OR change the maximum turn radius.
Measure Time when half the reaction occurred.
 Multiple trials are needed at every different setting of
initial amounts used, at each experiment.
Presentations and Reflections