Soda pop fizz

Oxygen Carbon Oxygen atom atom atom 

Hydrogen Oxygen Hydrogen atom atom atom 

We will explore the nature of atoms, molecules, and chemical bonds more fully in later chapters. For now, think of atoms and molecules as tiny particles that compose all common matter, and chemical bonds as the attachments that hold atoms together. 

The details of how atoms bond together to form a molecule—straight, bent, or some other shape—as well as the type of atoms in the molecule, determine everything about the substance that the molecule composes. The characteristics of water molecules make water a liquid at room temperature. The characteristics of carbon dioxide molecules make carbon dioxide a gas at room temperature. The characteristics of sugar molecules allow them to interact with our taste buds to produce the sensation of sweetness. 

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Examine Figure 1.1 and, from a molecular point of view, explain why soda pop fizzes. What molecules are inside the bubbles in a glass of soda pop ... 

Warm soda pop fizzes more than cold soda pop because the solubility of the dissolved carbon dioxide decreases with increasing temperature. 

Gas-and-Liquid Solutions The temperature and pressure dependence of gas solubility is the reason that soda pop fizzes when opened and the reason that warm soda goes flat. 

How does gas solubility depend on pressure How does this relationship explain why a can of soda pop fizzes when opened. 

Why does a freshly opened can of soda pop fizz, and why does fhe soda go flaf after a time To answer questions like these requires an understanding of the solubilities of gases. As discussed in this section, the effect of temperature on the solubility of gases is generally different from that on solid solutes. Additionally, the pressure of a gas strongly affects its solubility. 

Mr. Dexheimer s fizz s uniqueness, though, is its color—not a light raspberry soda-pop red, but a deep, mature, Baroque painter s red. Like blood, or velvet. That s when the experts stepped in. 

A much healthier option than soda pop, this spritzer contains fruit juice, which is acidic, as well as alkalizing baking soda to add fizz. Drink only in moderation. 

Carbon, usually found as a black solid, reacts with oxygen in the air to form carbon dioxide, an unreactive gas that produces the fizz in soda pop. 

Polar solvents such as water usually do not dissolve nonpolar substances. However, nonpolar CO2 is slightly soluble in water but under pressure, even more CO2 dissolves. Bottling soda pop with CO2 under pressure adds the fizz. When you release the pressure by opening the bottle, the CO2 comes out of solution—sometimes too fast. 

Carbon dioxide is a very familiar molecule that is the product of human respiration and of the combustion of fossil fuels. This gas also puts the "fizz" in soda pop. It turns out that the simple, familiar CO2 molecule has profound implications for our continued existence on this planet. 

Soda pop is a mixture of carbon dioxide and water and a few other substances that contribute flavor and color. When soda pop is poured into a glass, some of the carbon dioxide molecules come out of the mixture, producing the familiar fizz. 

The makers of soda pop use pressure (the result of collisions between gaseous molecules and the surfaces around them) to force gaseous carbon dioxide molecules to mix with liquid water molecules. As long as the can of soda is sealed, the carbon dioxide molecules remain mixed with the water molecules, held there by pressure. When the can is opened, the pressure is released and carbon dioxide molecules escape out of the soda mixture (T Figure 1.1). As they do, they create bubbles—the familiar fizz of soda pop. 

FIGURE 1.1 Where the fizz comes from Bubbles in soda pop are pockets of carbon dioxide gas molecules escaping out of the liquid water. 

Solutions of Gases in Water How Soda Pop Gets Its Fizz 452... 

FIGURE 13.6 Pop Fizz Acan of soda pop is pressurized with carbon dioxide. When the can is opened, the pressure is released, lowering the solubility of carbon dioxide in the solution and causing it to come out of solution as bubbles. 

The clear plastic bottles used for carbonated beverages (sometimes also called soda, pop, or soda pop) are made from poly(ethylene terephthalate) (PET). The fizz in pop results from dissolved carbon dioxide (CO2) because PET is permeable to CO2, pop stored in PET bottles will eventnally go flat (i.e., lose its fizz). A 20-oz. bottle of pop has a CO2 pressure of about 400 kPa inside the bottle, and the CO2 pressure outside the bottle is 0.4 kPa. 

Even unpolluted rain can contain both acids and bases. For example, carbon dioxide naturally present in air dissolves in rain to form carbonic acid (H2CO3), the weak acid responsible for the fizz in soda pop. If there were no other substances in rain, CO2 would lower the acidity from neutral (pH 7.0) to weakly acidic (pH 5.6). Unpolluted rain also contains small amounts of acid sulfate and acid nitrate that are produced in the stratosphere. These acids would further lower the natural pH of rain to about 5.4. Several alkaline substances partly neutralize the acidity in rain Ammonia, which is naturally present in the air, dissolves in rain to form ammonium salts. Soil dust containing alkaline minerals such as limestone (calcium carbonate) and dolomite (magnesium carbonate) can dissolve in rain and raise its pH. Fly ash from coal combustion contains calcium and magnesium oxides, which also are alkaline. The pH of rain therefore reflects the competing influence of several different substances. 

We see a practical application of Henry s law in carbonated beverages. The dissolved gas is carbon dioxide, and the higher the gas pressure maintained above the soda pop, the more CO2 that dissolves. When a bottle of soda is opened, some gas is released. As the gas pressure above the solution drops, dissolved CO2 is expelled, usually fast enough to cause fizzing. In sparkling wines, the dissolved CO2 is also under pressure, but rather than being added artificially as in soda pop, the CO2 is produced by a fermentation process within the bottle. 

Pop Rocks is a carbonated candy like soda is a carbonated beverage. The fizzing that goes on in your mouth is due to carbon dioxide (CO2) bubbles escaping from the candy. To make this unique treat, the ingredients are heated, exposed to high pressures of carbon dioxide, and then cooled to trap the CO2 inside the candy. 

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