Forming Carbon Dioxide

The carbon m methane has the lowest oxidation number (—4) of any of the com pounds m Table 2 4 Methane contains carbon m its most reduced form Carbon dioxide and carbonic acid have the highest oxidation numbers (+4) for carbon corresponding to Its most oxidized state When methane or any alkane undergoes combustion to form carbon dioxide carbon is oxidized and oxygen is reduced A useful generalization from Table 2 4 is the following... 

These equations tell us that the reverse process proton transfer from acids to bicarbon ate to form carbon dioxide will be favorable when of the acid exceeds 4 3 X 10 (pK, < 6 4) Among compounds containing carbon hydrogen and oxygen only car boxylic acids are acidic enough to meet this requirement They dissolve m aqueous sodium bicarbonate with the evolution of carbon dioxide This behavior is the basis of a qualitative test for carboxylic acids... 

Fuel. Natural gas is used as a primary fuel and source of heat energy throughout the iadustrialized countries for a broad range of residential, commercial, and iadustrial appHcations. The methane and other hydrocarbons react readily with oxygen to release heat by forming carbon dioxide and water through a series of kinetic steps that results ia the overall reaction,... 

Oxyfluoride ions are discharged at the anode, forming carbon dioxide [124-38-9] and aluminum fluoride. The first oxygen can be removed more readily from Al2 02F4 than either the second or the oxygen from Al2 0Fg ... 

Cosmetics and Toiletries. Citric acid and bicarbonate are used in effervescent type denture cleansers to provide agitation by reacting to form carbon dioxide gas. Citric acid is added to cosmetic formulations to adjust the pH, act as a buffer, and chelate metal ions preventing formulation discoloration and decomposition (213—218). 

Surface oxidation short of combustion, or using nitric acid or potassium permanganate solutions, produces regenerated humic acids similar to those extracted from peat or soil. Further oxidation produces aromatic acids and oxaUc acid, but at least half of the carbon forms carbon dioxide. 

An alternative surface reaction which has been suggested is a reaction between an adsorbed oxygen atom with an adsorbed carbon monoxide molecule to form carbon dioxide which is immediately desorbed. The reaction rate is again given by the equation above. 

Chemical Reactivity - Reactivity with Water Slow, non-hazardous. Form carbon dioxide gas Reactivity with Common Materials data not available Stability During Transport Stable Neutralizing Agents for Acids and Caustics Not pertinent Polymerization May occur slowly. Is not hazardous Inhibitor of Polymerization Not pertinent. 

As the pH is further reduced to 4.3, the acid then reacts with the bicarbonate ions to form carbon dioxide and water. 

A solution ofpotassium permanganate reacts with oxalic acid, H2C204, to form carbon dioxide and solid manganeseQV) oxide (Mn02). 

Conversion of carbon to carbon monoxide. In the lower part of the furnace, coke burns to form carbon dioxide, C02. As the C02 rises through the solid mixture, it reacts further with the coke to form carbon monoxide, CO. The overall reaction is... 

The molecular formula for the substance formaldehyde is HsCO. Formaldehyde burns to form carbon dioxide and water. What equation represents this reaction ... 

Now let us talk with the business manager. He thinks in terms of gains and losses. He is likely to observe that the consumption of coal and water to generate water gas is followed by the combustion of the water gas to form carbon dioxide and water. Without knowing much chemistry, he can see that what is finally accomplished is the combustion of coal to form carbon dioxide. The overall reaction is obtained by adding reactions (7), (2), and (5) ... 

It was expected that an eggshell thickness of scale would form, but that it would be relatively soft and easily removed (despite normally containing some silicate and sulfate). However, a disadvantage of this method of internal control was that the carbonate degraded to form carbon dioxide, and at higher pressures the rate of breakdown was so great that the necessary carbonate reserve required to prevent sulfate scale often could not be maintained. (Never mind the danger to the steam and condensate lines from the production of carbon dioxide and ultimately carbonic acid.)... 

The thermodynamic properties of a chemical substance are dependent upon its state and, therefore, it is important to indicate conditions when writing chemical reactions. For example, in the burning of methane to form carbon dioxide and water, it is important to specify whether each reactant and product are solid, liquid, or gaseous since different changes in the thermodynamic property will occur depending upon the state of each substance. Thus, different volume and energy changes occur in the reactions... 

Processes represented by (a) are large entropy producers. Burning and decay reactions in which the energy released as heat is not utilized in producing work are of this type. For example, at a temperature of 298.15 K and a pressure of 0.1 MPa, the combustion of a mole of carbon to form carbon dioxide results in... 

Polyurethanes (PURs) are usually described as being prepared by the reaction of diols with diisocyanates. However, this is an oversimplification because often water is deliberately added in the production of flexible polyurethane foams. Unreacted isocyanate groups react with water to form carbon dioxide and urea groups in the polymer chain. The carbon dioxide acts as a blowing agent in the production of PUR foams. Also, polyurethanes can be formed by the reaction of bischloroformates with diamines. 

The composition of the gas mixture, which is introduced into the tube bundle reactor (tubes of 6-12 m length and 20-50 mm diameter, filled with the Ag catalyst) consists of 15-50 vol % ethylene, 5-9% oxygen, as much as 60% methane as dilution gas, and 10-15% carbon dioxide. The reaction therefore proceeds above the upper explosion limit. The ethylene conversion runs up to 10% per cycle through the reactor. The ethylene oxide selectivity amounts to 75-83 % maximum. The formed ethylene oxide is recovered by scrubbing with water and the newly formed carbon dioxide is separated from the cycle gas, e.g., by hot potash washing process. 

Sometimes we need to construct a balanced chemical equation from the description of a reaction. For example, methane, CH4, is the principal ingredient of natural gas (Fig. H.3). It burns in oxygen to form carbon dioxide and water, both formed initially as gases. To write the balanced equation for the reaction, we first write the skeletal equation ... 

FIGURE H.3 When methane burns, it forms carbon dioxide and water. The blue color is due to the presence of C2 molecules in the flame. If the oxygen supply is inadequate, these carbon molecules can stick togelher and form soot, thereby producing a smoky flame. Note that one carbon dioxide molecule and two water molecules are produced for each methane molecule that is consumed. The two hydrogen atoms in each water molecule do not necessarily come from the same methane molecule the illustration depicts the overall outcome, not the specific outcome of the reaction of one molecule. The excess oxygen remains unreacted. 

Suppose that 2.00 L of propane gas, C3Hg, at 1.00 atm and 298 K is mixed with 5.00 L of oxygen gas at the same pressure and temperature and burned to form carbon dioxide gas and liquid water. Ignore the volume of water formed, and determine the final volume of the reaction mixture (including products and excess reactant) at 1.00 atm and 298 K if reaction goes to completion. 

Self-Tfst 6.11B When 0.338 g of pentane, C5H12, burns in an excess of oxygen to form carbon dioxide and liquid water in the same calorimeter as that used in Self-Test 6.1 1A, the temperature rises by 76.7°C. Write the thermochemical equation for the reaction. 

If aerobic respiration continues to completion, all of the organic material is oxidized to form carbon dioxide and water. Much more energy is... 

Chemical reactions in which oxygen atoms become attached to other elements are termed oxidations. Such reactions almost always result in the release of energy in the form of heat. Some oxidations are rapid, like the burning of wood or natural gas, with the evolution of heat and light. In this case, the oxygen combines with the carbon in the materials being oxidized (burned) to form carbon dioxide. 

When charcoal bums in air, carbon atoms combine with oxygen atoms from molecular oxygen to form carbon dioxide. One molecule of carbon dioxide contains one carbon atom and two oxygen atoms. Experiments on carbon dioxide show that each molecule is linear, with a carbon atom in the middle. Draw a molecular picture that illustrates this reaction. 

Propane, which is used as a fiiel for gas barbecues, reacts with molecular oxygen to form carbon dioxide and water C3 Hg + O2 CO2 + Hg O To determine if this equation is balanced, make a list of the elements and numbers of atoms on each side ... 

C05-0090. Carbon monoxide and molecular oxygen react to form carbon dioxide. A 50.0-L reactor at 25.0 °C is charged with 1.00 atm of CO. The gas is then pressurized with O2 to give a total pressure of 3.56 atm. The reactor is sealed, heated to 350 °C to drive the reaction to completion, and cooled back to 25.0 °C. Compute the final partial pressure of each gas. 

The fuels of modem society—natural gas, petroleum products, and coal—are called fossil fuels because they are formed from the decomposition of green plants over many millions of years. Like glucose, fossil fuels release energy when they react with oxygen to form carbon dioxide and water. 

A process may be spontaneous, and yet the process may not occur. Extending our water example, water can be stored behind a dam for a very long time unless a spillway is opened. A chemical example is the reaction of methane and oxygen to form carbon dioxide and water ... 

Electron-transfer reactions occur all around us. Objects made of iron become coated with mst when they are exposed to moist air. Animals obtain energy from the reaction of carbohydrates with oxygen to form carbon dioxide and water. Turning on a flashlight generates a current of electricity from a chemical reaction in the batteries. In an aluminum refinery, huge quantities of electricity drive the conversion of aluminum oxide into aluminum metal. These different chemical processes share one common feature Each is an oxidation-reduction reaction, commonly called a redox reaction, in which electrons are transferred from one chemical species to another. 

Oxalic acid is relatively stable by itself it decomposes at a temperature starting at its melting point, which corresponds to 189.5°C, forming carbon dioxide, monoxide, formic acid and water. 

R. N. Diyashev, F. M. Sattarova, K. G. Mazitov, V. M. Khusainov, K. I. Sulejmanov, G. S. Karimov, and I. R. Diyashev. Recovering oil not exploited from reservoir—by injecting alternating portions of ammonium carbonate and hydrochloric acid and displacing formed carbon dioxide with water. Patent RU 2065940-C, 1996. 

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