Please answer the questions 13-16 marked as the âREPORT FOR EXPERIMENT 3â by reading the first 4 pictures if it helps.
EXPERIMENT 3 Preparation and Properties of Oxygen MATERIALS AND EQUIPMENT Solids: candles, magnesium (Mg) strips, dry yeast, fine steel wool (Fe), wood splints. Solution: 3 percent hydrogen peroxide (HOp), pneumatic trough, 20 to 25 em length rubber tubing, 25 X 200 mm ignition tube, five wide-mouth (gas-collecting) bottles, five glass cover plates. DISCUSSION Oxygen is the most abundant and widespread of all the elements in the earth's crust. It occurs both as free oxygen gas and combined in compounds with other elements. Free oxygen gas is diatomic and has the formula O2 Oxygen is found combined with more elements than any other single element, and it will combine with all the elements except some of the noble gases. Water is 88.9 percent oxygen by mass and the atmosphere is about 21 percent oxygen by vol- ume. Oxygen gas is colorless and odorless, and is only very slightly soluble in water, a prop- erty important to its collection in this experiment. Oxygen may be obtained by decomposing a variety of oxygen-containing compoun of these are mercury(ID oxide (HgO, mercuric oxide), leadIV) oxide (PbO2, lead dioxide), potas- sium chlorate (KCIO,), potassium nitrate (KNO,), hydrogen peroxide (H02), and water (H,O). In this experiment oxygen is produced by decomposing hydrogen peroxide, and five bottles of oxygen will be collected by the downward displacement of water. After collection, some the physical and chemical properties of oxygen will be observed. A. Decomposition of Hydrogen Peroxide to Generate Oxygen Hydrogen peroxide decomposes very slowly at room temperature. The rate of decomposition is greatly increased by adding a catalyst, manganese dioxide. Although manganese dioxide contains oxygen, it is not decomposed under conditions of this experiment. These equations represent the changes that occur Word Equation: Hydrogen peroxide Water + Oxygen Formula Equation: 2H,0,la)H,oN)+ 0g) B. Collection of Oxygen The oxygen is collected by a method known as the downward displacement of water. The gas is conducted from a generator to a bottle of water inverted in a pneumatic trough