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Physical And Chemical Changes Lab Report

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Title: Physical and Chemical Changes

Purpose: Recognize and distinguish between chemical and physical changes

Apparatus and Material: evaporating dish, Bunsen burner, wood splint, test tubes, micro spatula, dropper, mortar and pestle, test tube holder, safety goggles, lab apron.
Piece of paper, NaCl (sodium chloride), water, 6 M HCL (hydrochloric acid), 0.1 M AgNO3 (silver nitrate), Mg ribbon, 6 M HCL (hydrochloric acid), CuSO4 5 H2O, 0.50g iron fillings, 0.50g of powdered sulfur, magnet, copper sulfate solution, zinc metal

Safety: When heating a substance in a test tube, be sure the open end of the test tube points away from yourself and others. Handle all acids with extra caution. Always wear safety goggles when handling acids. …show more content…

Heated crystals change color from blue to white; water vapor forms on the walls of the test tube. Addition of water turns the heated crystals from white back to dark-blue, almost teal color.
5. Sulfur appears as yellow powder; iron is dark-brown powder; mixed together, they look like dirt. Iron becomes attracted to the magnet, following it if it’s close enough; sulfur does not. Magnet can be used to separate the two mixtures.
6. On heating the iron-sulfur mixture, the sulfur melts and reacts with the iron exothermically to first evaporate into a yellow gas, then form a reddish-orange, solidified substance that “glows”. The substance releases an unpleasant odor of rotten eggs. The iron on the bottom turns black and does not react with a magnet. The glowing substance turns out to be a soft solid when probed.
7. Zinc is a silver solid with a light mass. Addition of zinc metal to copper sulfate solution results in an exothermic reaction that produces a brown-reddish precipitate (copper). Zinc becomes coated with the copper precipitate, thus becoming dark.

Conclusions and data:
1. a) tearing paper – physical change; retaining of properties, no new substances created
b) burning paper – chemical change, gas and heat given off (evidence of chemical reaction)
c) dissolving NaCl – physical change; solution formed, but individual properties retained; separation possible by distillation.
d) mixing NaCl and AgNO3 - chemical change; white precipitate, or

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