Module 4 DBA notes

e) Geothermal energy being used to heat water to turn turbines and produce electricity is a physical change because the geothermal energy never reacts with anything to produce a new substance. The energy is merely being transferred from one place to another, under the ground to pipes. Even the turbines moving due to the heated water is a physical change because they are not chemically reacting with anything.

Combustion Reaction: A chemical reaction between a fuel and an oxidizing agent that produces heat.

The purpose of the lab was to determine the ratio of air to acetylene results in complete combustion of acetylene gas. The balanced chemical equation for this experiment was C2H2(g) + O2(g) --> CO2(g)+ H2O(l). Complete combustion is the reaction of an element or compound with oxygen to produce the most common oxides and energy. Complete combustion occurs when the fuel and oxygen combine in exact proportions to completely burn the fuel, which leaves a clean test tube. Incomplete combustion is the reaction of an element or compound with oxygen to produce some oxides with less oxygen than the most common oxides. Incomplete combustion occurs when there is not enough oxygen to react

The energy released during combustion reactions goes into the surrounding atmosphere because the energy does not disappear it simply goes into the atmosphere of a surrounding area. For example, during the Cheeto experiment the fire being released is the energy but when the fire is out the rest of that energy is moved onto its surrounding like people and the air. One observation that I made during my experiment was when the mass of Cheeto was too big and when the Cheeto began to burn it released its energy onto the can which heated the water inside and that also created energy because the water releases steam and that goes into the air and the people around it. The fire being released wasn't always as expected because if the Cheeto was too big

There are now many classification systems to classify the different types of reactions. These include decomposition, polymerization, chain reactions, substitute reactions, elimination reactions, addition reactions, ionic reactions, and oxidation-reduction reactions.

A chemical reaction is a process that involves change of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction. The key concepts of a chemical reaction are:

| Combustion product reacted by becoming cold, dissolving, and no gas formation with an end product is clear colorless solution.

The difference between endothermic and exothermic reactions is that endothermic reactions absorb heat, and exothermic give off heat. Dilution of ammonium chloride is an example of an endothermic reaction. This is the active ingredient in chemical ice packs you can obtain in a pharmacy. Other reactions are melting and boiling which also absorb heat to happen, although you may not consider them chemical reactions. Combustion is a typical exothermic reaction any type of burning.An exothermic reaction occurs if the energy of the bonds formed in the products

Chemical reactions make new things by rearranging other things. In a chemical reaction, the main change that occurs relates to the way atoms are bonded to each other, in order to change those connections, bonds must be broken and new bonds be formed.

Physical changes can be seen through an altering of the substances physical property. A substances physical property is observed and measured without changing the composition of the subject. Descriptive words that would help to identify a substance’s physical property include hard, soft, brittle, flexible, heavy, and light just to name a few.

A chemical reaction is a process in which elements or compounds react with one another to create new or different substances. There are two parts to a reaction. Those two parts are the products and the reactants. The reactants are the chemicals or chemical compounds that are going through the reaction itself. The products are chemical elements or chemical compounds that are produced as a result of the reactant or reactants reacting. There are four key indications that there’s a chemical reaction is taking place. Those four signs include a change in color and/or odor, formation of a precipitate or a gas, the release or absorption of energy (light, heat, electricity), and if the reaction is irreversible. Along with this information, there are ways to predict the products of a reaction.

Charcoal is the most commonly used fuel in fireworks. The fuel loses electrons (a negatively charged subatomic particle.) to atoms within the oxidiser. During this process, bonds are formed between the fuel and oxygen atoms forming a stable product. A small amount of energy is required to start combustion of this fuel-oxidiser compound. When combustion starts, the result is a release of energy

Human activities, for instance, burning of fossil fuels lead to the release of greenhouse gasses into the atmosphere. The gasses build up in the air holding in more heat. Coal, oil, and natural gas have a high content of carbon. When these fossil fuels are burned, they produce an enormous quantity of carbon dioxide. For example, when a gallon full of gasoline is burned, the carbon dioxide discharged into the atmosphere is about 19 pounds. Since the Industrial Revolution, the amount of carbon dioxide that has been tracked coming from burning of oil,

There is also an incomplete combustion, meaning it is burned in an air lacking oxygen. If the oxygen is not enough, the carbons turn to carbon monoxide. Carbon monoxide is very harmful to living organisms.

Syngas is a gas mixture of hydrogen and carbon monoxide, which are products from gasfireing any hydrocarbon material such as coal at a high pressure and temperature, 30 bar and 1500 °K. The present of the oxygen is the primary difference between gasification and combustion. When a feed gasfire, the oxygen or air is injected in small amount allowing part of the feed to burn completely which supply the required heat and pressure, then, the heat will break down the feed into synthesis gas (Higman & Burgt, 2003). This process consists of six main reactions: