November 19, 2014 Homework : Quiz on Tues. 11/25 Organize notes on Physical and Chemical Change into a T- Chart --- may draw pictures as well. Complete on copy paper-Use a ruler Do Now: Agenda- Homework Update T.O.C- pg. 37-Observing Chemical reactions Open textbooks to pg. 18- Add Precipitate to Log of Sci. terms (pg. 30). Open binders to pg. 36-Evidence of Chemical Change
Contrast Physical and Chemical Change Make a T- Chart similar to the one started below: Physical ChangeChemical Change Liquid Water –Freezing into snow/Ice (solid) Cooking an Egg The parts of water do not Change, just its form, it Is still H 2 O
1 2
Evidence of a Chemical Reaction TThere is a formation of gas w hich can be seen by a fizzing or bubbling TThe reaction will cause heat ( temperature Change ), light or odor to be emitted- Changes in chemical properties AA color change i s produced AA solid ( precipitate ) is formed during the change
On the back of pg. 36 The key characteristic of a chemical reaction is the production of new materials that are chemically different from the starting materials. Let’s see…
What happens to the mass of the matter during chemical reactions? A Chemical change, or Chemical Reaction, is like scrambling the letters of a word to make new words. Ex: Elements Steel + Men Were any of the letters removed? Law of Conservation of Mass- Matter can not be created or destroyed in any physical/ chemical change or reaction only (made) into something else. Atoms are rearranged
Which of these pictures is an example of a physical change ? Which is a chemical change ? -Write a C for Chemical and P for the Physical. Post it popcorn Chopping Wood Burning Logs
November 20, 2014 Homework: Complete Section 1 Review Sheet- Quiz on Tuesday- “Section Notes/Study Guide,” online. Do Now: Agenda - Write Homework-Take out ( P & C Change T-Chart ) Get Your and two partners lab journals Update Lab Journal T.O.C pg. 5 -Alka Seltzer to the rescue! Begin writing materials list and procedure on pg. 5
Alka Seltzer to the Rescue Lab Questions to consider for observations: Look for Evidence of a Chemical Reaction Did any of these things happen? There is a formation of gas which can be seen by a fizzing or bubbling The reaction will cause heat, light or odor to be emitted A color change is produced A solid is formed during the change
Conclusion Questions- Record in Journal 1) Using your observations- What evidence do you have that a chemical reaction took place when you added the alka-seltzer to the water? 2) Describe how you think this experiment relates to the Law of Conservation of Mass? (What were your results?) 3 )Write your own definition of the law of conservation of mass. 4 )What is another experiment you could think of doing that could produce similar observations?
November 21, 2014 Homework: Study for quiz Tuesday- Use online notes/ study guide, T- Chart, Review sheet etc… Make Flash Cards Do Now: (6 Minutes) Agenda- Write Homework- Take out Section 1 Review Sheet. Get your and a Lab partners Lab Journal Review Homework Answers with a partner
Section 1 Review…. 1.Atom 2.Compound 3. Solution 4.Chemical Reaction 5.Precipitate 6.Mixture 7.Chemical Bond 8.Molecule 9.Element 10.Chemistry EventObservable Changes Type of Change Baking a CakeColor becomes golden brown- gooey liquid to crumbly solid Chemical Burning a logColor turns black, changes from wood to dusty ashes Chemical Freezing waterColor becomes cloudy white, changes from liquid to solid Physical
Conclusion Questions- Record in Journal 1) Using your observations- What evidence do you have that a chemical reaction took place when you added the alka-seltzer to the water? 2) Describe how you think this experiment relates to the Law of Conservation of Mass? (What were your results?) 3 )Write your own definition of the law of conservation of mass. 4 )What is another experiment you could think of doing that could produce similar observations?
A Chemical reaction occurs when substances go through chemical changes The reaction cannot be reversed to return the two original substances through a physical process. Like scrambling the letters of a word to make new words.