Next Generation
Chemistry II
Kaye Truitt, Don Bratton, Tina Wagner
MSMS
Qualitative Analysis of Six Common
Substances Using Patterns of Reactivity
boric acid
cornstarch
magnesium sulfate
sodium bicarbonate
sodium chloride
sucrose
Standards
MS Chemistry Framework:
Inquiry 1
F: data analysis (DOK 3)
G: draw conclusions from data to use technology for formal
presentation (DOK 3)
Physical Science 2
A: describe and classify matter based on physical and
chemical properties (DOK 1)
E: compare properties of compounds according to their type
of bonding (DOK 1)
Physical Science 3
C: classify chemical reactions by type (products and
solubility rules)
Standards
Next Generation Science Standards:
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 patterns of chemical properties.
Science & Engineering Practices:
Planning and carrying out investigations
Disciplinary Core Ideas:
PS1.A The PT orders elements horizontally by the number of
protons in the atom's nucleus and places those with similar
chemical properties in columns. The repeating patterns of the
table reflect patterns of outer electron states.
Cross-cutting Concepts: Patterns
Different patterns may be observed at each of the scales at
which a system is studied and can provide evidence for causality
in explanations of phenomena.
Qualitative Analysis
Compounds and reagents easily acquired
Reagents:
Water, iodine, vinegar, NaOH, alcohol, heat
Minimal equipment needed
Qualitative Analysis
Substances have similar physical properties
regarding appearance
Use patterns in reactivity and other physical
properties such as melting point to identify
substances
STEM: qualitative analysis is critical in chemical
industry, food industry, medicinal chemistry
Qualitative Analysis
Uses critical thinking to isolate one compound at a
time.
For inquiry-based activity, eliminate flow chart and
give reactivity patterns for types of compounds (i.e.,
carbonate reactions with acids) and allow students to
create a flow chart for analysis.
Iodine Clock Kinetics
http://www.youtube.com/watch?v=C5tOEBmBAHg
Iodine Clock Kinetics
Chemical Kinetics
Study of factors affecting the rate of reaction and of
mechanism of reaction
Mechanism: Step-by-step molecular pathway of a
reaction
Experimental chemistry
Iodine Clock Kinetics
Key Concept: Rate Law
Mathematical expression of rate with respect to
concentration of reactants only
NH4+ + NO2-  N2 + 2 H2O
Rate = k[NH4+][NO2-]
aA + bB  cC + dD
Rate = k[A]m[B]n
Iodine Clock Kinetics
Key Concept: Rate Constant
Represented by k in the rate law
Must be mathematically determined
Units vary with number of reactants and coefficients
Iodine Clock Kinetics
Key Concept: Reaction Order
Exponents (m and n) in rate law
Often expressed as “The order of the reaction with
respect to X”.
Can be 0, and sometimes even fractional
Iodine Clock Kinetics
Rate Laws and Mechanisms
Some reactions have multiple steps
NO2 (g) + CO (g)  NO (g) + CO2 (g)
NO2 (g) + NO2 (g)  NO3 (g) + NO (g) (slow)
NO3 (g) + CO (g)  NO2 (g) + CO2 (g) (fast)
The steps of a reaction mechanism must sum to the
overall reaction equation
The slowest step determines the rate and the rate law
Iodine Clock Kinetics
2010 MCF Alignment (Chemistry)
4.d Describe and identify factors affecting the solution
process, rates of reaction, and equilibrium. (DOK 2)
And most of the inquiry standards
Iodine Clock Kinetics
NGSS Alignment
HS-PS1-5: Apply scientific principles and evidence to
provide an explanation about the effects of changing
the temperature or concentration of the reacting
particles on the rate at which a reaction occurs.
Iodine Clock Kinetics
Materials (different from video)
0.05 M KI solution
1% starch solution
0.01 M sodium thiosulfate solution
1.0 M sulfuric acid solution
0.05 M hydrogen peroxide solution
Glassware
Iodine Clock Kinetics
It is important to have a baseline to measure how
factors affect kinetics
Ensure that all students measure the baseline
reaction several times to get an average
Slight differences in execution can affect the timing
The base reaction on the handout takes
approximately 1 minute to react
5 microscale reactions to produce various gases (CO2,
NO2, NH3, O2, H2)
Splint tests to identify CO2, O2, H2
Lime water also identifies CO2
Litmus test to identify NH3
Brown gas = NO2
Inquiry “twist”
Determine a metals’ placement on the activity series
based on whether hydrogen gas is evolved /
produced.
Mississippi 2010
Framework
INQUIRY - 1. Apply inquiry-based and problem-solving processes and skills to
scientific investigations.
Physical Science
3. Develop an understanding of the periodic table.
c. Classify chemical reactions by type. (DOK 2) Single displacement,
double displacement, synthesis (combination), decomposition,
combustion, or precipitation. Products (given reactants) or
reactants (given products) for each reaction type
dbratton@themsms.org
http://bratton.themsms.org
ktruitt@themsms.org
cwagner@themsms.org