Macroscopic Evidence Of Chemical Change Essay

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

Example 1: The baking soda (NaHCO3) mixed with vinegar (CH3COOH) created foam as well as the washing soda (Na2CO3) when mixed with the vinegar.
Example 2: The color change when the starch and iodine (I2) mixed. As well as the color change when the red cabbage was combine with the vinegar and ammonia.
Example 3: When the Epsom salt (MgSO4) was combined with the vinegar (CH3COOH) it had settled at the bottom and did not mix.

2. Which reactions, if any, do you believe showed no evidence of chemical change? Justify your reasoning. (15 points)

I believe the baking soda (NaHCO3) and the clear ammonia (NH3) had no reaction because both substances are basic. As in

NaHCO3 baking soda and vinegar CH3COOH forms CO2.

5. What happened when starch was used? Based on your observations, how could iodine be used to test for the presence of starch? Test at least 3 other substances in your house using the iodine, to determine if starch is present. Suggestions include different types of paper, bread, vegetables, etc.
Describe what happened, and which substances you tested contained starch. (25 points)

The iodine turned a dark blue almost purple color when it was combined with starch. I tested iodine on a piece of cut potato and once in contact it turned a dark blue-purple color therefore stating starch was present. I also placed starch on a piece of paper, when it cam in contact the iodine just ran but did not change color. Lastly I tested the starch on a piece of white bread. Immediately it absorbed the iodine but did not change color therefore there was not starch.

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