Chemical Change
Signs a Chemical Change has occurred.1. Color - Color change from beginning to end, be cautious as this may be fool's gold.
2. Energy- fizzing, bubbling, foaming, sound, or heat gain or heat loss - A combination of these are sure to indicate chemical change. 3. Gas/Odor - Being able to detect an odor(good or bad) that wasn't previously there is definite indication of chemical change because a new substance is being created. 4. Solid/Precipitate - Creating a new solid/liquid that wasn't previously there is definite indication of chemical change because a new substance is being created. 5. Can't Change back - There are some physical changes that can't be reversed, so be cautious as this may be fool's gold. Below is slideshow used in class for Chemical Change - includes exothermic/endothermicPost Lab - Chemical Change![]()
Name:___________________
POST LAB- CHEMICAL CHANGE 30-point assignment (5 points each) 1-4. Pick 4 scenarios from following list and answering all of following questions. a) Physical or Chemical Change? b) Color ? c) Energy? d) Gas/Odor? e) Solid/Precipitate? f) Can’t change back? · Milk Souring · Sugar being dissolved in hot tea · Egg being cooked in skillet · A popsicle melts · Bread gets moldy · Crushing oranges to make orange juice 5. What is difference between exothermic and endothermic reactions? Explain what is going on with bond making and/or bond breaking. Use one example from class and come up with one on your own. 6. What role does a catalyst have in a reaction? Do all chemical reactions need catalysts? (2 points) 7. The Law of Conservation of Mass states that nothing will be destroyed during chemical reaction, in other words the reactants = the products. Pick any chemical reaction you want and balance both sides of reaction; include chemical name and chemical formula. If this is confusing to you just use examples of balanced reactions we have done in class. (3 points) |
Fireworks Web Quest![]()
Name:_________
Fireworks Web Quest 20-point assignment 1. Locate 4 chemical compounds used in fireworks. List Chemical Name, Chemical Formula, color it burns and draw Chemical Diagram of how atoms fit together. (each worth 4 points) a) b) c) d) 2. List 1 credible website used – (Not Google, yahoo or any other search engine) 1 points 3. What century are earliest known fireworks used? (1 point) 4. What country gets credit for earliest fireworks) (1 point) 5. How many fireworks used in world’s largest display? (1 point) Helpful websites: 1. http://www.scifun.org/CHEMWEEK/fireworks/fireworks.htm 2. http://chemistry.about.com/od/fireworkspyrotechnics/a/fireworkcolors.htm Below is data for Bar Graphs (exothermic & endothermic reactions)
Reaction A - Baking Soda & Vinegar
57/59 Groups reported endothermic reaction for a 96% success rate 1st Period - (42.1 F) 2nd Period - (46.0 F) 3rd Period - (46.6 F) 8th Period - (47.2 F) 9th Period - (45.2 F) Reaction B - Hydrogen Peroxide & Yeast 52/59 Groups reported exothermic reaction for a 88% success rate 1st Period - (39.7 F) 2nd Period - (44.3 F) 3rd Period - 34.4 F) 8th Period - (39.0 F) 9th Period - (43.0 F) |