The main objective of this experiment is to differentiate between a physical change and a chemical change. A physical change includes a change in the material without affecting its composition, such as the physical state change. However, a chemical change includes the change in the composition of the substance. The change in color, formation of a gas or a solid product, and the production of energy are the evidences of a chemical reaction, thus, of a chemical change. ? Materials Crucible tongs Evaporating dish Glass rod Test tubes Test tube rack
Thermometer Analytical balance Magnesium ribbon pH paper 1M copper (II) sulfate Iron metal 6M hydrochloric acid ? Procedure Magnesium and oxygen test A small strip of magnesium metal is held on one end with a pair of crucible tongs, while the other end is ignited with the flame of Bunsen burner. The burning ribbon is held over a clean evaporating dish so that the ash formed falls into the dish. When the burning is complete, about 10 drops of water were added to the ash formed in the evaporating dish and the contents are stirred with a clean glass rod.
Then, a pH paper is touched with the tip of the rod which is wet with the solution. Iron and copper (II) sulfate About 3ml of 1M copper (II) sulfate is placed in a small test tube where a screw, piece of iron metal, is added into the solution. Changes observed after one, five and fifteen minutes are to be recorded. Iron and hydrochloric acid A small test tube is half filled with 6M aqueous hydrochloric acid solution. The test tube is then placed in the test tube rack and a thermometer is inserted into the solution to measure its temperature.
The Essay on Test Tube Starch Solution Water
Detection of Biological Molecules Introduction: Without carbon, nitrogen, hydrogen, sulfur, oxygen and phosphorus, life wouldn't exist. These are the most abundant elements in living organisms. These elements are held together by covalent bonds, ionic bonds, hydrogen bonds, and disulfide bonds. Covalent bonds are especially strong, thus, are present in monomers, the building blocks of life. These ...
A clean iron strip, a screw, is placed into the test tube after weighing its initial mass using the analytical balance. A change in the temperature is to be recorded. The iron strip is removed after 10 minutes from the solution, washed with water and reweighed. ? Results Magnesium and oxygen test When burning the magnesium ribbon, heat and energy were produced. The ribbon was transformed into grey ash. When the tip of the rod touched the pH paper, the color of the pH paper became blue. Iron and copper (II) sulfate
After 1 minute, a slight change in the color of the iron strip was noticed. It became somehow darker. After 5 minutes, the iron strip color starts to change. After 15 minutes, the iron strip was corroded (its color was reddish brown), and the color of the solution slightly changed to green. Iron and hydrochloric acid Initial temperature of the 6M aqueous HCl: 28 °C Initial iron strip mass: 0. 472 g Highest temperature observed: 28. 5 °C Bubbles were observed. Mass of the final iron strip: 0. 469 g
