Physical and Chemical Changes Chemistry Lab Report

Procedure: In this experiment, various chemicals were mixed together, to determine a reaction. Using two drops from chemical 1 and two drops of chemical two, unless otherwise stated, then recording the type of physical reaction or color changes that occurred.

6. We added 1.0 mol dm-3 of NaOH into tube #7 until a change in color is observed.

In this experiment you will observe some physical and some chemical changes. You will observe that energy must be used to start some chemical reactions, and that it is produced in others.

Heavy precipitate emerged immediately and solution turned white in color; solution then became opaque and turned light, bright blue in color.

| After ignition of magnesium light and toxic fumes are made, and white powder (2MgO or Magnesium Oxide) is left over.

The objective of the experiment was to observe different reactions with different chemicals. The experiments emphasized on the chemical changes occurring in acids and bases as well as color changes and bubble formations. The experiments allowed for a better understanding of the undergoing chemical changes in mixtures. Some mixtures instantly changed colors while others were transparent or foggy. Some mixtures produced thick color that created solids called precipitates. Mixtures KI + Pb(NO3)2 and NaOH + AgNO3 both produce noticeable precipitates after a while. It was interesting to see the different acidic and base reactions like the fuchsia color formation in NaOH + phenolphthalein.

For example, in the experiment when I poured Hydrochloric acid in a test tube and then one magnesium ribbon, the substances started to bubble. Other than that, when I took the wooden split and lit it, I burned the green paper and it changed brown around the edges of the paper.

2) Adding OH⁻ would react with the Fe³⁺ in the system to form a precipitate Fe(OH)₃. This would decrease the [Fe³⁺] in the system. Equilibrium will shift left to counteract the change and the solution becomes lighter yellow in colour.

The first reaction involves pyrite rock reacting with oxygen (air) and water to produce dissolved ferrous iron, sulfate, and acidity. The second reaction oxidizes the dissolved ferrous iron in acidic conditions and produces ferric iron and water. The third reaction involves the hydrolysis of the ferric iron to form ferric hydroxide and more acid. The ferric hydroxide is the orangey-red colored solid you see in the water (Juniata College).

The chemical reaction that occurred was a combustion reaction, it is an exothermic reaction in which something reacts with oxygen and then ignite into a burning white bright light. One of the products used was magnesium, magnesium is a silvery white metallic chemical element, it forms a thin layer around itself to help prevent itself from rusting when exposed to air. In the experiment The magnesium was reacting with oxygen in the air and not with the fire. Fire is the heat and light produced when things burn. Magnesium reacts with oxygen to make a compound called magnesium oxide.

A few more important terms to keep in mind when doing a lab with chemical and physical changes are

Once all of the copper has reacted, the solution is diluted with distilled water, changing the solution from a dark brown to a pale blue color.

The color of zinc oxide turns from white to yellow when heating and reverts back to original color after cooling

Our group worked with copper and magnesium metals and aqueous solution of zinc sulfate. A small strip of copper was placed into a test tube containing colorless zinc sulfate solution. A small strip of copper about the same size was place into a test tube containing colorless zinc sulfate solution.

At the end of the experiment when the lid was removed, it was found out that the blue colour of the copper (II) sulphate solution has faded away. It was turned to pale grey and there were some precipitates present. It was the zinc powder that was in excess to ensure that the copper (II) sulphate solution could react fully with the zinc powder.