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Identification Of Chemical Change Lab Report

Decent Essays

CHM130

Lab 3

Identification of Chemical Change

Name: Nolan Strommer

A. Data Table (24 points)

Place your completed data table here:

Reactants Predictions Before
Combining Observations After
Combinin g
Starch + I2 It becomes purple It becomes blue and a little purple.
Food coloring + NaOCl The color of the food coloring will disappear. The color of food coloring is on the top of NaOCI, NaOCI is under the food coloring.
Food coloring + CH3COOH The color will be the same as the food coloring The color becomes to the food coloring color.
Food coloring + NaOCl
+ CH3COOH It will have foam and the food coloring color. It has foam in the color of the food coloring.
Red cabbage + NH3 It becomes green It becomes green and a little yellow. …show more content…

MgSO4 + NH3 The result will be a sediment It has a little precipitate.
MgSO4 + Na2CO3 Nothing will happen It has a little white precipitate.

B. Follow-Up Questions

1. What type of macroscopic evidence for chemical change did you observe during this experiment? Give at least three different examples. (15 points)
Answer:

The first example of macroscopic change I observed is the color change from the combination of Starch + I2. The second example of macroscopic chemical change is the sediment formed by the combination of MgS04 and NH3. The third example is the foam from the mixture of Na2CO3+ CH3COOH
2. Which reactions, if any, do you believe showed no evidence of chemical change? Justify your reasoning. (15 points)
Answer:

The combination of NAHCO3 and NH3 is a reaction that does not show any changes from a chemical standpoint. This is due to the fact that both of these compounds are bases and therefore do not have a reaction.

3. When two solutions combine and a solid substance is formed, this solid is called a precipitate. In your experiments, if the clear reactant solutions you combined together formed a cloudy product, then a precipitate (solid substance) was formed. Describe the precipitates (according to color and clarity) and the substances that formed them. (18 …show more content…

Therefore Iodine can be utilized to detect the presence of starch since the reaction of I2+ I- gives us I3 - . What this means is that any substance that becomes blue/black after iodine has been added to it proves that the substance has starch in it. Interestingly enough, when Iodine is added either to white rice or sweet potatoes, these two foods turn to the blue black color that confirms the presence of starch. However, If I add iodine to a banana, it only turns yellow which confirms that the banana does not contain iodine.

6. Red cabbage juice is a natural, universal indicator. When a solution of red cabbage is red to pink, it indicates that a solution is acidic. When it is green to yellow, it indicates that a solution is basic. When it is purple to blue, it indicates a solution is neutral. Would you characterize vinegar and ammonia as acids or bases? Explain. (15 points)
Answer:
Vinegar is acid because red cabbage juice+CH3COOH will become red and a little pink. Ammonia is base because NH3 which ammonia contains add red cabbage juice will become green and

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