Chemoluminescent Demo At the start: Luminol solution: clear blue liquid Hydrogen peroxide: clear liquid What we saw: Glowing blue color and then an ugly brown color Bubbles Temperature rose about 7-8 ºC Signs of a chemical reaction: Energy change (light, heat), gas formation, color change
Burn, Baby Burn Signs we see: Color change-wood went from beige to black Odor change- smell the burning wood Gas formation (CO 2, CO, etc…) Energy exchange-light, heat Mass went from ~1 gram to ~0 grams How can this be? Did we lose mass? No, it escaped as gas If we captured the gas the mass would be the same
Curses Foiled Again At the start Solution 1 was a blue liquid (Copper chloride CuCl 2 ) Aluminum foil was a silver solid (Al) At the end The solution was now clear (Aluminum Chloride AlCl 3 ) There was a red/brown solid precipitate (copper Cu ) What happened: 2Al + 3CuCl 2 2AlCl 3 + 3Cu Copper and chlorines bond breaks Aluminum and chlorine bond Copper falls out of solution (precipitate) Signs we saw to indicate a chemical reaction: color change, precipitate formation
Pittsburgh Sheep At the beginning Solution 2 was clear (Vinegar) Steel wool was grayish/blackish/silver (has iron in it) At the end Solution 2 was clear Steel wool has brownish/reddish spots on it- THIS IS RUST, NOT A PRECIPITATE!! What happened: 3Fe + O 2 -> Fe 2 O 3 When iron from the steel and oxygen from the vinegar meet they bond together to give you rust Signs we saw to indicate a chemical reaction: heat exchange, color change, maybe odor change?
The Gas We Pass At the beginning: Powder 1- Sodium Bicarbonate (NaHCO 3 ) Solution 2- Vinegar (with acetic acid)(CH 3 COOH) At the end: Carbon dioxide (CO 2 ) Water (H 2 O) Sodium Acetate(NaCH 3 COO) What happened: NaHCO 3 + CH 3 COOH CO 2 + H 2 O + NaCH 3 COO Signs we saw to indicate a chemical reaction: precipitate formation, gas formation, color change (slight), energy change
Cabbage Water At the beginning: Solution 2- Vinegar (with acetic acid)(CH 3 COOH) was clear Solution 3- Laundry Detergent was blue Solution 4-Cabbage water (pH indicator) was purple At the end: Test Tube A: Solution 2 + Solution 4= a pink colored liquid Test Tube B: Solution 3 + Solution 4= a greenish blue colored liquid What happened: Vinegar w/acetic acid is more acidic (has more H+ ions) and therefore turns pink Laundry detergent is more basic (has less H+ ions) and therefore turns green Signs we saw to indicate a chemical reaction: color change, energy change
Elephant Toothpaste Before: Hydrogen Peroxide – Clear liquid Potassium iodine solution – cold, cloudy, yellowish liquid What happened: Created potassium and iodide ions in water and oxygen gas KI + 2 H 2 O 2 2H 2 0 + O 2 +K + I Signs of a Chemical Reaction Gas formation, Energy change, Odor change, Color change