Observation of Chemical Change
By: yetta26 • Lab Report • 1,665 Words • February 10, 2015 • 664 Views
Observation of Chemical Change
Observation of Chemical Change
Lab Report 1
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SECTION 1: Chemical Change
Abstract
The objective of the experiment was to determine a substance is transformed into a chemically different substance. When hydrogen burns in air for example it undergoes a chemical change because it combines with oxygen to form water. In physical change a substance changes it physical appearance but not it composition.
Chemical changes are determined by how a substance reacts with one or more substances when forming compounds. These reactions are known as chemical reactions. Not all chemicals will react when mixed with another chemical; while some chemicals can be explosive or toxic when mixed with other chemicals.
Experiment
The experiment was determining the chemical change.
1. To observe some properties of chemical reactions
2. to associate chemical properties with household products
Chemical changes are often accompanied by physical changes. Three that you should not see in this lab are changes in temperature, presence of a flame, and evolution of light, as when as firefly glows. Three physical changes that indicate a chemical change may have occurred (and that may be seen in this lab) are:
1. Color changes
2. Precipitate (formation of a solid)
3. Formation of gas bubble
No preliminary dilution of my test chemicals were necessary as Lab Paq provided pre-diluted chemicals. Utilizing the 96-well plate, 2 pipet drops of each chemical were added to the wells in the following combinations: a) NaHCO3+HCl b) HCl+Bromthymol blue c) NH3+1 drop Bromthymol blue d) HCl+blue dye e) Blue dye+NaOCl followed by HCl f) NaOCl+KI followed by various test foods g) KI+Pb(NO3)2 h) NaOH+phenolphthalein i) HCl + phenolphthalein j) NaOH+AgNO3 k) AgNO3+NH3 l) NH3+CuSO4. Along the way, observations were made pertaining to the reactions witnessed. This experiment concluded with testing household chemicals and proper disposal of lab chemicals
Data Tables and Observations:
Times | Chemicals | Reaction |
8am until 12pm | NaHCO3 and HCI-CO2 | Bubbles did not fizz and continued to occur until all of the liquid from the well was gone. Homogeneous. Bleach-like smell Clear bubbles; bubbles did not fizz and continued to occur until all of the liquid from the well was gone. Homogenous. Bleach-like smell. |
12pm till 4pm | HCI and BTB | Golden Yellow Clear Liquid Amber Clear Liquid and Turned orange, homogenous Turned into an amber color, homogenous |
4pm till 8pm | NH3 AND BTB | Royal Blue Clear Liquid Dark Blue Opaque Liquid and Turned dark blue, but did not leave a stain on the toothpick; homogenous Still resembled a dark blue, NOT black; did not leave stain on toothpick; homogenous |
8pm till 12am | HCI AND BLUE DYE | Emerald Green Clear Liquid Dark Green Opaque Liquid and Turned dark blue, stained toothpick with dark blue color; homogenous Seemed to be entirely black; homogenous |
7am till 11am | Blue dye and NaOCL | Observe, then add 1drop of HCl. Turned dark blue, but with time it turned into an aqua blue; stained toothpick with aqua blue; homogenous Looked nearly black at first, but as it grew lighter, it looked more grey; homogenous |
11am till 3pm | KI and Pb(NO3)2 | Bold yellow, seems solid and cloudy; with time created white/yellowish solids at the bottom of the well; precipitated Bold yellow, seems solid and cloudy; with time created white/yellowish solids at the bottom of the well; precipitated |
3pm till 7pm | NaOH and phenolphthalein | homogenous Still resembled a dark fuchsia; homogenous |
730pm till 1145pm | HCI and phenolphthalein | CLEAR; no bubbles; homogenous CLEAR; no bubbles; homogenous |
8am and 12pm | NaOH and AgNO3 | Bold brown, chocolate milk color(?), seems solid and cloudy; with time create white/brownish solids at bottom of the well; precipitated Bold brown, chocolate milk color(?), seems solid and cloudy; with time create white/brownish solids at bottom of the well |
1230pm till 415pm | AgNO3 and NH3 | Clear seems to be some small bubbles/solids at the bottom |
435pm till 840pm | NH3 and CuSO4 | Cloudy aqua blue, seems solid and cloudy; with time created white/blue-is solids at bottom of the well; precipitated Cloudy aqua blue, seems solid and cloudy; with time created white/blue-is solids at bottom of the well; |