Why Boiling Water

By 1952 the United States and the Soviet Union had detonated 11 nuclear weapons. Ten of these weapons used plutonium to produce their fission—an element that was not even discovered until 1940. While uranium is a naturally occurring element, plutonium is so rare that useful quantities can only be produced by exposing uranium to neutrons. When neutrons move through the uranium inside a reactor core, some of the uranium atoms will capture a neutron and be converted into flie heavier element plutonium, 

Filbum, S. Bullard, Three Mile Island, Chernobyl and Fukushima, 

As the US nuclear program continued after flie war, the Chicago Pile 1 had demonstrated the ability to build and control a nuclear fission reactor and had provided useful technical and operational information about running a nuclear reactor. However, the Chicago Pile 1 was never intended to bean industrial reactor, and it was not capable of converting large quantities of into Pu. Instead, new larger reactors in much more 

Graphite, water, and heavy water (DjO) have been used as neutron moderators in a variety of nuclear core designs. Prior to 1952, it was felt that water could only be used as both a moderator and a coolant inside a reactor core while it remained in its liquid phase. The large density difference between water and steam meant that with liquid water, one thousand times more water molecules are available per cubic foot within the core to slow neutrons down and remove the heat of the fission process. Thus, it was thought that if steam formed inside the core it would produce nuclear and thermal instabilities. The large variation in molecular density inherent in the boiling process was presumed to be a detriment to stable core operation. 

Although the AEC was nominally in charge of both peacetime and military atomic applications, the political realities of the cold war meant that the AEC emphasized weapons development and modernization. Commercial reactor development was a tertiary priority. With a deep commitment to its military mission, the AEC oversaw the detonation of the first thermonuclear fusion weapon in 1952. This new class of weapons demonstrated a 500x increase in explosive power over flie original fission weapons the initial thermonuclear weapons provided yields equivalent to ten million tons of TNT versus the approximately twenty thousand tons of TNT produced by the Little Boy and Fat Man fission bombs. 

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This explains why bums from steam are more painful than those from boiling water. 

We have now discussed three types of intermolecular forces dispersion forces, dipole forces, and hydrogen bonds. You should bear in mind that all these forces are relatively weak compared with ordinary covalent bonds. Consider, for example, the situation in HzO. The total intermolecular attractive energy in ice is about 50 kj/mol. In contrast, to dissociate one mole of water vapor into atoms requires the absorption of928 kj of energy, that is, 2(OH bond energy). This explains why it is a lot easier to boil water than to decompose it into the elements. Even at a temperature of 1000°C and 1 atm, only about one H20 molecule in a billion decomposes to hydrogen and oxygen atoms. 

A molecular perspective reveals why energy must be supplied to boil water. A molecule of water cannot escape the liquid phase unless it has enough energy of motion to overcome the hydrogen bonding forces that hold liquid water together. About 40 kJ of heat must be supplied to transfer 1 mol of water molecules from the liquid phase into the vapor phase. 

Why does a kitchen gas burner glow yellow when a pot of boiling water... 

Why does water boil more quickly in a kettle than in a pan on a stove ... 

Why does a cup of hot coffee yield more steam than above a cup of boiling water at the same temperature ... 

If natural gas is used to produce electricity in a power plant, however, the efficiency is much lower—around 37%. Why The heat from the burning natural gas is used to boil water. The kinetic energy of the resulting steam is transformed to mechanical energy for turning a turbine. 

For further experimentation, perform step 3 in two pots side by side. In one pot, use warm water from the kitchen faucet. In the second pot, use boiled water that has cooled down to the same temperature. You ll find that boiling deaerates the water, that is, removes the atmospheric gases. Chemists sometimes need to use deaerated water, which is made by allowing boiled water to cool in a sealed container. Why don t fish live very long in deaerated water ... 

Ice floats in room-temperature water, but does it float in boiling water Why or why not ... 

Why do bubbles in boiling water get larger as they rise to the surface ... 

First, note the water level in the level indicator shown in Fig. 15.4. It looks quite a bit lower than the water level inside the kettle. Why Well, because the water inside the kettle is boiling water. The water density has been reduced by the bubbles of steam. I have discussed this problem in great detail in Chap. 7, in the section on level control. Basically, the difficulty is that the water in the level indicator has a specific gravity of about 1.0. The boiling water in the kettle has a specific gravity of perhaps 0.5. If we have 4 ft of boiling water in the kettle, then, by pressure balance, we will have 2 ft of cool water in the level indicator. 

The fish often die and sink to the floor of the aquarium. Why There is no oxygen in distilled or boiled water. How does a fish get oxygen ... 

Such hydrogen bonds create an intermolecular force that joins multiple water molecules together in a group and affects their behavior. Hydrogen bonds are actually just extremely strong dipole-dipole interactions. This is why it takes a lot of energy to boil water compared to other liquids that do not contain hydrogen bonds. 

Explain why the protein in egg white coagulates (becomes insoluble) when it is heated in boiling water. 

Try to suggest some safe, alternative methods of reducing weeds, insects, and harmful microorganisms. For example, could boiling water be used as an effective herbicide Would this method of reducing weeds cause more problems than it would solve Why or why not ... 

As mentioned earlier, the boiling point of water is 100°C or 373 K. Why does this phenomenon occur at this temperature Does it always occur at this temperature Is it true that water will boil at 100°C or 373 K provided that the atmospheric pressure is 760 torr A temperature of 100°C or 373 K is what is referred to as the normal boiling point of water, the temperature at which water will boil when the atmospheric pressure is 760 torr. But why does water boil at this temperature When water is heated to 373 K, the vapor pressure of the water molecules is 760 torr, a vapor pressure that is exactly the same as... 

A liquid boils at the temperature where the vapor pressure of the liquid equals the external pressure. Thus the boiling point of a substance, like the melting point, depends on the external pressure. This is why water boils at different temperatures at different elevations (see Table 16.9), and any cooking carried out in boiling water will be affected by this variation. For example, it takes longer to hard-boil an egg in Leadville, Colorado (elevation 10,150 ft), than in San Diego (sea level), since water boils at a lower temperature, 89°C, in Leadville. 

Why is a burn from steam typically much more severe than a burn from boiling water ... 

Explain why steam produces much more severe burns than the same amount of boiling water does. 

Why will water in a flask begin to boil at room temperature as air is pumped out of the flask (Chapter 13)... 

At atmospheric pressure, the temperature of a pot of boiling water remains at 100°C, when heat is added. The best explanation as Lo why the added energy does not raise the temperature is that ... 

Wash the dyed material in boiling water as long as color is removed. Dry. Compare the appearance of the three pieces of cotton cloth. Why is the piece which was treated with tannic acid and tartar emetic darker than the one mordanted with tannic acid alone ... 

Which egg will cook faster—the one in ice water (left) or the one in boiling water (right) Why—in terms of what you have learned in this chapter ... 

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