1. Physical Science Chemical Reactions—Day 21 Materials Needed:
Writing Utensil
Folder
Notebook

2. Day 21 Bell work: Balance the following chemical equation:
C H2  C2H6
Agenda
Signs of a Chemical Reaction Lab
Notes on signs of a chemical reaction
Complete Lab Report
Exit Ticket

3. Q1: What is a characteristic of non-metals?
They are brittle.
They are malleable.
They have a shiny luster.
They have good electrical conductivity.
SC h DOK.1

4. Mathematics Booster
Pure gold is 24-karat (24K). Gold that contains 18 parts gold and 6 parts other metals is 18-karat gold. The percentage of gold in 18K is found by dividing the amount of gold by the total amount of the material and then multiplying by 100%. For example, (18 parts gold)/(24 parts gold) equals 0.75 x 100% = 75% gold. Find the percentage of gold in 10K and 14K gold.

5. Greek/Latin Greek/Latin Meaning therm heat e, ef, ex out, out of, very
endo
inside, within
-ic
nature of, like
caus
burn, heat

6. Today’s Objective I will know the signs of a chemical reaction.
I will be able to identify the signs of a chemical reaction.

7. Bell Work Answer Balance the following chemical equation:
C H2  C2H6

8. A1: What is a characteristic of non-metals?
They are brittle. – Correct. Nonmetals will break when pounded or hammered.
They are malleable. – Incorrect. Metals are malleable.
They have a shiny luster. – Incorrect. Metals have luster.
They have good electrical conductivity. – Incorrect. Metals have good conductivity.
SC h DOK.1

9. Mathematics Booster 10 parts gold ÷ 24 parts gold = 0.4167
x 100 = 41.67%
14 parts gold ÷ 24 parts gold =
x 100 = 58.33%

10. Explanation of Lab
The following slides show pictures of the lab procedures as well as expected results.
The first few slides of this presentation are included in the class presentation to demonstrate correctly using the Ziploc bag as a reaction container.

11. Procedure: Setting Up the Bag
Obtain a reaction container (zipper type bag). Fold the bag in the middle from top to bottom.

12. Procedure: Setting Up the Bag, cont’d
Making sure to keep the chemicals separate, place a half spoon full of calcium chloride (CaCl2) in one corner and place a half spoon full of sodium bicarbonate (NaHCO3) in the other corner.
Make and record observations of the two compounds.

13. Procedure: Adding the Indicator
Measure out approximately 10 mL of indicator solution.

14. Procedure: Adding the Indicator, cont’d
While being careful not to let the indicator solution contact the CaCl2, add the indicator solution to the NaHCO3 side of the bag. Gently mix the solution and compound. Make and record any observations.

15. Procedure: Adding the Indicator, cont’d
Now add 10 ml of indicator solution to the CaCl2 side of the bag. Gently mix the solution and compound. Make and record any observations.

16. Procedure: Mixing the Solutions
Seal the bag, then allow the two solutions to mix. Gently agitate the bag to ensure complete mixing.

17. Procedure: Mixing the Solutions, cont’d
Make and record any observations.

18. Procedure: Mixing the Solutions, cont’d
Be careful to watch for over inflation of the bag. If the bag gets too full open the top and reseal it.

19. Lab Report – Individual
A summary of your procedures.
Your observations of reactants, reactants plus indicator, and products.
Results of the lab.
What type of reaction did you observe in this lab?
Possible sources of error
How to improve the lab
Write a balanced chemical equation for the reaction.
Let students know that the balanced chemical equation will be difficult, but they should try to figure out what is happening in the reaction.

20. Lab Write-Up Rubric Tasks 0/1 2 3 4 Statement of problem & Hypothesis
Statement of problem and hypothesis are not present or neither is correct.
Statement of problem or hypothesis is present and correct.
Statement of problem and hypothesis is present and correct.
Variables
None or minimal number of the variables are present
A partial list of variables are present and some are placed under the correct heading
The majority of the variables are present and are placed under the correct heading
All of the variables are present and placed under the correct heading.
Materials
No list of materials present
Partial list of materials present
Complete list of materials present
Procedure, including Diagrams when necessary
Procedures are not present or are too confusing/incomplete to be understood
Procedures are unable to be recreated because of disorganization or omissions
Procedures are descriptive and could be recreated.
Complete sentences used. Diagrams are present to illustrate procedures
Observations
(data table, graph, statistics)
Data table isn’t used.
Data table includes inaccurate or incomplete data
Data table is satisfactory.
Table includes accurate data.
Data tables are very clean and neat. Tables include accurate data.
Analysis & Interpretation of results
Analysis and Interpretation are missing or too confusing/incomplete to be understood
Analysis and Interpretation are present but may be incomplete.
Analysis and Interpretation are present and easily understood. Logic and scientific thinking are shown.
Analysis and Interpretation are well written and show close analysis of the data. Interpretations are insightful.
Possible experimental errors
No statement of errors or incorrect errors that may have occurred while making measurements during the lab activity.
States a minimal number of errors that may have occurred while making measurements during the lab activity.
States the majority of errors that may have occurred while making measurements during the lab activity.
Conclusion
Conclusion is incomplete and/or not tied to the purpose
Explanation of support or nonsupport of purpose.
A conclusion summarizing what the student learned during the lab is present.
Purpose proved/disapproved.
Detailed explanation of how data was analyzed and supported
Recommendation for further experimentation
No recommendation is made
Recommendation is incomplete or unclear.
At least one correct recommendation is made for further investigation.
At least one correct recommendation is made for further investigation and a short explanation is included.

21. Homework
Finish Lab write-up

22. Exit Ticket
Provide two signs of a chemical reaction.