Evidence of a Chemical Change Lab

INDICATORS OF CHEMICAL REACTIONS

Formation of a gas

Emission of light or heat

Formation of a precipitate

Color change

Emission of odor

4. Exothermic reactions release heat and feel warm to the touch. List all of the exothermic reactions from this lab (2 Points). 5. Endothermic reactions absorb heat and feel cool to the touch. List all of the endothermic reactions from this lab (1 Point). 6. For each of the reactions below, indicate if they represent a chemical (C) or a physical (P) change (2 Points). a. 2Fe(s) + 3Cl2(g) 2FeCl3(s) e. CH3COOH(I) CH3COOH (g) b. H2O(l) H2O(g) f. 2K(s) + 2H2O(1) 2KOH(aq) + H2(g) C. SO2(s) SO2(g) g. Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g) d. 2KCIO3(s) 2Cl(s) + 302(g) Th. (NH4)3PO4(s)>(NH4)3PO4(aq) 7. For each of the following statements, indicate if they describe a chemical (C) or a physical (P) change (2 Points). a. Dissolving sugar in water. b. Burning wood. c. Decomposing water into hydrogen and oxygen gases. d. Boiling water. e. Producing salt from sodium and chlorine gas. f. Freezing carbon dioxide gas to produce dry ice (solid carbon dioxide). g. Generating nitrogen trihydride from its elements. h. Making a solution of calcium chloride dissolved in water