Download 3_2: More Chemical Changes

3_2: More Chemical Changes
November 6 & 7, 2014
Do Now
• Give three signs that tell you that a chemical
change has happened.
Objective
• I can determine whether chemical
reactions have taken place, and cite
my evidence using P-FARTS in a
‘Chemical Reactions Investigation’.
Agenda
1.
2.
3.
4.
5.
6.
Do Now, Objective (10 min)
Investigate: Chemical Reactions (20 min)
Analysis Questions (15 min)
Chemical Reaction Demo (10 min)
You ARE The Reaction (10 min)
Weekly Quiz (15 min)
Reminder
Unit 2 Test Retakes
Thursday – after school
Friday – lunch
Questions must be corrected with
explanations to retake!!
HOMEWORK
• Make a decorative poster explaining 4-6 signs
that show a chemical reaction has taken place.
• The top 3 signs will be laminated and displayed in
the classroom to help you during labs and quizzes
• See Ms. B if you need paper, markers, etc. to take
home for the night.
• DUE MONDAY/TUESDAY
Weekly Review
• New Words:
– Chemical change
– Physical change
– Chemical reaction
– Reactants
– Products
– Concentration
– Unsaturated Solution
– Saturated Solution
– Supersaturated Solution
Investigate: Chemical Reactions
• In today’s lab, you will be looking at chemical
reactions that occur between 8 different solid
materials. The solids have been dissolved in
water to make solutions.
Barium nitrate (Ba(NO3)2)
Sodium hydrogen
carbonate (NaHCO3)
Potassium iodide (KI)
Iron (III) nitrate (Fe(NO3)3)
Sodium hydroxide (NaOH)
Copper (II) sulfate (CuSO4)
Silver nitrate (AgNO3)
Hydrochloric acid (HCl)
“Wellplates”
Ba(NO3)2
Ba(NO3)2
NaOH
NaHCO3
CuSO4
KI
NaOH
NaHCO3
CuSO4
KI
Thought Questions
• Answer questions 1-7 on the back of data
table 1.
Chemical Reaction Demo
• Combine baking soda (NaHCO3) and calcium
chloride (CaCl2) in a plastic bag.
1. Quickly add 10 mL of distilled water and
reseal the bag.
What happens? What do you see? Feel?
Think Pair Share
• Did a chemical reaction occur between the
baking soda and the calcium chloride? How do
you know?
The Chemical Reaction!
• When baking soda and calcium chloride are
combined they produce an aqueous solution of
sodium chloride and calcium carbonate along with
carbon dioxide, water, and heat.
2NaHCO3(aq) + CaCl2(aq)  2NaCl(aq) + CaCO3(s) + H2O(l) + CO2(g)
REACTANTS
PRODUCTS
When I test this solution with litmus paper, it turns yellow. This shows
me that the chemicals produced are ACIDS (pH 1-6)
The Chemical Reaction!
What are the names of the reactants? The products?
2NaHCO3(aq) + CaCl2(aq)  2NaCl(aq) + CaCO3(s) + H2O(l) + CO2(g)
REACTANTS
PRODUCTS
Weekly Recap
• You learned about the differences between chemical
and physical changes
• You learned that solutions are made of a solute and a
solvent
• You learned that solutions have different
concentrations (concentrated or dilute)
• You learned that solutions can be unsaturated,
saturated, or supersaturated
• You learned that chemical reactions ususally produce 1
or more P-FARTS (precipitates, formation of a gas,
aromas, replacement, temperature change, or new
substance)
Weekly Quiz
• Complete your weekly quiz silently. When you
are finished turn your quiz in, and put away
your materials.
Procedures – Part 1
1. Add 1 drop of barium nitrate (Ba(NO3)2) to boxes 1-7 on
your “wellplate”
2. Add 1 drop of sodium hydroxide to box 2
3. Write down any observations (remember P-FARTS) on
data table 1
4. Add 1 drop of sodium hydrogen carbonate to box 3
and write down your observations on data table 1
5. Add 1 drop of copper (II) sulfate to box 4 and write
down your observations on data table 1
6. Continue to mix different solutions using the rubric on
your ‘wellplate’. MAKES SURE TO WRITE DOWN YOUR
OBSERVATIONS
Data Table Symbols
• NRx = no reaction
• PPT = precipitate
• Soln = solution