mp4pd5Group+1

Combination: H20 + NaHCO2 = Observation is that the temperature drops. The NaHCO2 is dissolving. The water became clear and it was an endothermic reaction. H20 + CaCl2 = Observations is that the temperature is going up. The CaCl2 dissolved and the liquid became cloudy. It was an exothermic reaction. Bromothymol Blue + Calcium Cloride = Observations is that there is no color chnge. Exothermic reaction. NaHCO3 + CaCl2 + H20 = Observations is that it produced a gas of carbon dioxide. There was bubbles and the water then turned pure white.



Summary: During this lab, some of the reactions were that they dissolved, the color changed, a gas formed, and most of the time, the temperature changed. H2O + NaHCO3 dissolved, absorbed energy, became clear, and the temperature dropped, making it an endothermic reaction. H2O + CaCl2 dissolved, the water got cloudy, and it let off energy making it an exothermic reaction. BB + CaCl2 + (H2O) did not have any color change, and was an exothermic reaction because the temperature went up. CaCl2 + NaHCO3 + H2O a participate formed, it was not soluble and it settled out, it produced a gas, and was an endothermic reaction. NaHCO3 + BB dissolved and was an exothermic reaction. NaHCO3 + CaCl2 + BB + (H2O) turned yellow and a gas formed; foam formed on the top of the liquid and turned green then went down. Lastly, CaCl2 + NaHCO3 only mixed together, and the temperature increased.

Experimental Design: Question: What are signs of a chemical reaction taking place? Hypothesis: Oder, color change, bubbles, creation of a precipitate are signs of a chemical reaction taking place Independent variable: The combinations of chemical in the test tubes. Dependent Variable: Signs of chemical reactions. Constant: The chemicals

Chemical Equation: Pb(NO3)2+2NaI=2Na(NO3)+PbI2

Conclusion:


 * In almost all of the chemical combinations experienced a temperature change. The temperature changed when the bonds in the chemical reaction were broken to form new compounds. Some examples of this happening were in all of the experiments we did.
 * A color change is also an indicator of a chemical reaction. In H2O + CaCl2 the calcium chloride dissolved but the water became cloudy. In CaCl2 + NaHCO3 + H2O there was also a color change, it turned white. This is because the CaCl2 and the NaHCO3 dissolved in the H2O. The last example of a color change was the NaHCO3 + CaCl2 + BB + H2O. There was an immediate change, it turned yellow and the foam on the top turned a light shade of green. A color change occurs when something dissolves or when Bromothymal Blue is exposed to an acidic solution.
 * When a gas (or bubbles) from, it means that a chemical reaction formed. In CaCl2 + NaHCO3 + H2O and NaHCO3 + CaCl2 + BB + H2O a gas was formed. A gas forms when the reaction lets off carbon dioxide.
 * The last indicator of a chemical reaction is when a precipitate forms. A precipitate forms when the chemical is not able to dissolve. In our lab, there was only one combination in which a precipitate formed, and that was during CaCl2 + NaHCO3 + H2O. After letting CaCl2 + NaHCO3 + H2O sit over night, the solid settled out to the bottom of the test tube. The solid was CaCO3.

= Background Information: = Chemicals-

1. Sodium bicarbonate
 * Slightly toxic if too much is consumed
 * Baking soda
 * Extinguish fire

2. Water
 * Nonflammable
 * Nontoxic
 * H20

3. CaCl2
 * Mechanical uses
 * soluble
 * Food additive

4. Bromothymol Blue
 * C27H28Br2O5S
 * Chemical indicator

Observations: H2O+NaHCO3-Dissolved,absorbed energy(temp. drop) becomes clear, endothermic. H2O+CaCl2- Starting 19.6 c, chemical-27.2 c, dissolved and let off energy(temp hot), exothermic- Cloudy water. BB and CaCl2(H2O)- Starting 21.7 c, no color change, exothermic, temp went up, stopped temperature 27.5 c.

Predictions: Water+CaCl2- I think that the CaCl2 will dissolve in the water and become foggy Bromothymol+CaCl2- I think it will become yellow and the CaC2 will dissolve. NaHCO3+H20- I think that the naHCO3 will dissolve and the H20 will become cloudy or foggy. CaCl2+NaHCO3-I don’t think they will really do anything but mix with each other. CaCl2+NaHCO3+H20- Temperature change, gas formed and precipitate formed. NaHCO3+BB- Temperature change and color change.

Equations:
 * H2O + NaHCO3 || H2O + CaCl2 || BB + CaCl2 + (H2O) || CaCl2 + NaHCO3 + H2O || NaHCO3 + BB || NaHCO3 + CaCl2 + BB + (H2O) || CaCl2 + NaHCO3 ||  ||
 * Water || Water || Bromothymol Blue || Calcium Chloride || Sodium Bicarbonate || Sodium Bicarbonate || Calcium Chloride ||  ||
 * Sodium Bicarbonate || Calcium Chloride || Calcium Chloide || Sodium Bicarbonate || Bromothymol Blue || Calcium Chloride || Sodium Bicarbonate ||  ||
 * ||  ||   || Water ||   || Bromothymol Blue ||   ||   ||