The History of Paint Pigments

Chem 111-404
April 24, 2013

Introduction:
This report expresses five different pigments that were formed during chemical reactions. Three out of the total five reactions went through a metathesis, or double-replacment reaction. A metathesis reaction can be defined as “a chemical reaction in which an element or radical in one compound exchanges places with another element or radical in another compound.” (Webster). The other two pigments underwent a neutralization reaction, which is “A reaction between an acid and a base that yields a salt and water.” (Webster). In both types of reaction two substances are being combined to form a new solution. The metathesis reaction produces a solution and a …show more content…

After the solution is centrifuged, the precipitate at the bottom was a thick white paste. Once it dried it became a white solid. When the gum Arabic, water, and the pigment were mized together it formed a white paint Thirdly, the synthetic malachite was made. When adding sodium bicarbonate to the copper sulfate, the chemical reaction produces cloudy blue mixture. Carbon dioxide is being produced which displays that this is a neutralization reaction. The solution was then split into two equal parts. The first part was filtered and set aside. After two weeks, the solid precipitate was added to the water and gum Arabic and created a watercolor paint. The second half of the solution remained in a beaker. When dried, the precipitate was added to the water and gum arabic and formed a light blue watercolor pigment. The final pigment was the prussian blue. This pigment was formed by the combination of iron (III) chloride and potassium ferrocyanide. This caused a chemical reaction producing a blue solution and a dark colored precipitate. The solution was filtered leaving the precipitate to dry for the completion of the experiment. Then after the two weeks, the precipitate was added to the gum Arabic solution creating an indigo colored paint. The picture below shows the use of the watercolor paints created in the lab. The watercolor paint is easy to paint with but tends to