IDENTIFYING CHEMICAL REACITONS
Class: Scientific Principles
Instructor: Abigail Carter
Perryville High School
Subject Area: Ninth Grade General Science
Chemistry Unit
Curriculum Objective: The students will be able to identify the main indicators used to identify a chemical reaction and, given a process, use these to evaluate whether a chemical reaction has taken place. (This lesson will take two 50-minute periods.)
Technology Objective:
Content Standard Alignment: (Missouri Show-Me Standards)
Sc-1, Sc-5, Sc-8
Process Standard Alignment: (Missouri Show-Me Standards)
Goal 1-8, 1-10, Goal 2-1
Learner Activity: Demonstration, paragraph writing, classification
Assessment Activity: Students will evaluate the process of welding and decide whether or not a chemical reaction has taken place between the two metals welded together.
Method of Assessment: The evaluation should be written in paragraph formula. The student should state clearly that a chemical reaction does not take place between the two metals and give 3 explanations to defend this position.
Background Knowledge: This lesson should be taught after discussions on matter, atomic structure, chemical and physical properties and changes and possibly also lattice/crystal structures of solids.
Instructional Method:
DAY 1
Bellwork: Take observation notes on what is demonstrated at the front of the room. Include everything you see, smell, and the most important things you hear.
Instructor demonstrates:
1) burn a strip of Mg
2) drop solid Zn into HCl
3) cut a piece of paper in two
4) glue two pieces of a broken solid object back together.
Purpose: (written on the board) We have discussed chemical and physical changes. Chemical changes occur only as a result of a chemical reaction – how can you tell when/if a chemical reaction has occurred?
Modeling/Guided Practice: Students share observations made of the 4 demonstrations. Classify each demonstration according to whether a chemical reaction occurred or not. Are there any similarities between the processes that we identified as chemical reactions?
Guided Practice: notes on chemical reactions – definition and list of factors used to identify (does the process produce light, color change, odor, ect.).
Independent Practice: Given 10 more example processes, decided if a chemical reaction has taken place or not. Explain your answer.
Check for Understanding/Closure: Go through answers to above.
DAY 2
Bellwork: Describe 3 chemical reactions you’ve encountered since waking up this morning – think about what you have seen, heard, felt, tasted.
Purpose: Does a chemical reaction occur when two metals are welded together?
Independent Practice: Reading on a general description of what is welding, the principle behind it and the goal.
Guided Practice: Discuss reading – discuss indicators of a chemical reaction and whether they are demonstrated in the process of welding.
Independent Practice: In a paragraph, discuss an answer to the question posed above.
Resources: strip of Mg, bunsen burner, matches, test tube, solid Zn, HCl, scissors, paper, broken object, glue, welding information packet (copied from welding text or internet), overhead projector