Magnesium reaction with water experiment

In this experiment a sample of magnesium will be reacted with air to foirm MgO and Mg3N2 The Mg3N2 will then be converted into MgO by reaction with water followed by drying. The original mass of magnesium, the mass of the product mixture, and the mass of dried total MgO are then used to perform two independent calculations of the percent composition by mass of the product mixture. 

The geochemical balance of a 103 acre watershed underlain by silicate bedrock was investigated. Base flow composition of the stream water was essentially constanty but flood flows showed a decrease in concentration of silica, bicarbonate, and sodium and an increase in sulfate, magnesium, calcium, and potassium. Laboratory experiments indicate that fresh rock or soil reacts rapidly with distilled water and achieves a composition similar to the stream water, suggesting control of water composition by reaction with the silicate minerals. The aluminosilicate minerals react with CO charged water to form kaolinite, releasing cations and silica to solution. The products of weathering are removed as particulate matter (0,28 metric tons per year) and dissolved material (1,5 metric tons per year). 

In the experiments using larger amounts of tetrabutylammonium bromide (0.5 to 1.0 equivalents), the reactions were done on 0.1 to 0.2 times the scale of the previous work (i.e., 4.535g of BPA). At the end of the reaction, the mixture was diluted with methylene chloride and the solution was extracted with water and the organic phase was dried over magnesium sulfate. The dried organic solution was added to methanol to give the polymer which was collected, dried, and analyzed. No further reprecipitation was required. 

Figure 11.6 An experiment showing magnesium reacting with steam. The steam is given off from mineral wool soaked in water at the right-hand end of the test tube. The white magnesium oxide formed is visible inside the test tube and the hydrogen gas produced in the reaction has been ignited at the end of the straight tube.

Everyday experience tells us that the rates of chemical reactions increase with increasing temperature. Familiar fuels such as gas, oil, and coal are relatively inert at room temperature, but burn rapidly at elevated temperatures. Many foods last almost indefinitely when stored in a freezer, but spoil quickly at room temperature. Metallic magnesium is inert in cold water, but reacts with hot water (Figure 12.13). As a rule of thumb, reaction rates tend to double when the temperature is increased by 10°C. 

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