Observations of Chemical Change

Topics: Chemistry, Green, Chemical reaction Pages: 5 (965 words) Published: July 18, 2013
Name: Jeanne Yoo|Date: 07/15/13|
Exp 1: Observations of Chemical Changes|Lab Section: 1411-76426| Data Tables:
Part 1:
|Chemicals|Well No.|Observations of the Reaction|
A.|NaHCO3 + HCl|1
|clear bubbles formed|
B.|HCl + BTB|2
|turned orange after BTB was added, transparent, acidic|
C.|NH3 + BTB|3
|turned dark blue after BTB was added, opaque, basic|
D.|HCl + blue dye|
|blue dye was missing from kit|
E.|Blue dye + NaOCl|
|blue dye was missing from kit|
| with the 1 drop of HCl|
||
F.|NaOCl + KI|4
|small white precipitate, color changed to black after starch was added | | with 1 drop of starch|
||
G.|KI + Pb(NO3)2|5
|turned bright yellow, milky texture|
H.|NaOH + phenolphthalein|6
|turned dark pink, magenta|
I.|HCl + phenolphthalein|7
|clear|
J.|NaOH + AgNO3|8
|turned brownish green, cloudy|
K.|AgNO3 + NH3|9
|turned light brown|
|after exposure to bright light|
||
L.|NH3 and CuSO4|10
|light blue, cloudy|
Part F: Testing of Various Foods with the NaOCl + KI solution

Foods|Presence or Absence of Starch|

bread|present|

tortilla chip|present|

broccoli|absent|

banana|present|

cheerios|present|

cheese|absent|

potato|present|

Part 2:
Household Chemicals with Bromthymol Blue

Use the empty pipet in the Auxiliary Supplies Bag to test several (at least 3) household items including household cleaning products with bromothymol blue. Rinse the pipet well before using it on the next household chemical. When finished with this experiment rinse the pipet well and return it to the Auxiliary Bag for use in future experiments. Name the items tested and record their results.

Household Chemicals|Well No.|Observations of the Reaction|
liquid detergent|
1|darker ring on outside, dark blue (bromothymol blue) sits on top of light blue detergent, basic | oxi clean (stain remover)|
2|bubbles, turns greenish yellow and after a while it turns dark yellow, acidic| bleach|
3|bromothymol blue dissolves once it touches the bleach and turns light yellow, acidic| |
||
|
||

Conclusion:
Objective
The objective of this experiment was to observe some properties of chemical reactions and associate chemical properties with household products. Also through the experiment, the presence of starches in food and the presence of an acidic or basic solution were measured by using the chemicals. Chemical changes result in a new substance.

Observation
Throughout the experiment, I observed chemical changes using two different chemical solutions. To determine if a chemical change had occurred, there were physical changes that correlated to these chemical changes such as formation of precipitate, changes in color, and development of gas bubbles. I learned how to determine whether a solution was acidic or basic by identifying the color created by the chemicals used. The bromthymol blue was used to determine if the solution was acidic or basic. Yellow color meant, green color meant and blue meant. If the solution turned yellow then it was acidic, if the solution turned green then it was neutral, and if the solution turned blue then the solution was basic. The hydrochloric acid is acidic because it turned yellow and the ammonia solution is basic because it turned dark blue.

One part of the experiment was to test the presence or absence of starch in food. I tested bread, a tortilla chip, banana, broccoli, cheese, cheerios, and potatoes to determine if there was starch in them. Starch was present in the bread, tortilla chip, banana, cheerios, and potato. This was determined by using the NaOCl and KI solutions with one drop of starch. If the food turns black, it is assumed that there is the presence of starch in these foods. In broccoli and cheese, there were no signs of starch.

Another part of the experiment was to see the results of household chemicals mixed with the bromothymol blue. I used liquid detergent, Oxi Clean (stain remover), and bleach for this experiment. The liquid...
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