Why Pressurized Water

The proper choice of material is now a quite different one. Reinforced concrete is now the best choice - that is why many water towers, and pressure vessels for nuclear reactors, are made of reinforced concrete. After that comes pressure-vessel steel - it offers the best compromise of both price and weight. CFRP is very expensive. 

Why does water take longer to heat in a pressure cooker than in an open pan ... 

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... 

C Why do water-based heat pipes used in the cooling of electronic equipment operate below atmospheric pressure ... 

You have probably noticed that the steam from a hot shower deposits liquid droplets on all the surfaces of your bathroom, but have you ever thought about what s happening on the submicroscopic level of atoms and molecules when this happens How does water vapor differ from liquid water, and why does water change from one state to the other (Note that we use the term vapor to describe the gaseous form of a substance that is liquid at normal temperatures and pressures. We also use it to describe gas that has recently come from a liquid.)... 

It is now easy to understand why ice, water, and vapour cannot coexist in equilibrium at temperatures below the triple point Since the vapour pressure of the supercooled water is greater than that of ice, vapour will condense on the ice, and a process of distillation will... 

The effect of pressure on boiling point also explains why pressure cookers save time in the kitchen. A pressure cooker is a sealed container that allows steam to escape only when it exceeds a certain pressure. The pressure above the water in the cooker is the sum of the atmospheric pressure and the pressure of the steam. Consequently, the water in the pressure cooker will boil at a higher temperature than 100°C and the food in it will be hotter and cook faster. 

So why is water a liquid rather than a gas at normal temperatures and pressures The answer has to do with something called intermolecular forces—forces that occur between the molecules. 

Explain why pressure substantially affects the solubility of O2 in water but has little effect on the solubility of NaCl in water. 

While Ne atoms repel one another at short range, there is a very weak attractive force when / > 310 pm. If no such attraction existed, neon would never condense to a liquid or freeze to a solid. (Condensation of a gas to form a liquid or a solid is not an effect of gravity. Why would water condense on the ceiling if it were ) This interatomic attraction also leads to deviation from ideal gas behavior at low temperatures and high pressures. 

Why are pressurized water extinguishers not found in chemistry laboratories ... 

In order to understand why liquid water is so unusual, it seems instructive to look at the phase behavior of water at subzero temperatures. Figure 1 shows schematically the regions in the P- Tplane where water is found as a stable liquid, supercooled liquid (metastable), and glass or amorphous ice (metastable). Liquid water is the stable phase above the melting temperature m(/). Below Tm P), the stable phase of water is ice the particular stable ice phase depends on pressure and temperature (see Figure 2). For clarity, the different ice phases are not indicated in Figure 1. 

Thus increasing the pressure from 1 atmosphere to 15 saves 70 mV and if on top of that we work at 105°C instead of 25 C the total saving will be 137 mV. Since in water electrolysis electricity costs are of overriding importance, the saving is worthwhile this is why most water electrolysis processes work at elevated temperatures and pressures. 

Therefore, the pressure at the top of the column is 5.26 - 4.69 = 0.57 ft liquid = 12.8 mm Hg. From Equation (22.41. assuming pure, saturated acetic acid at the top of the column, T = 21°C. Because cooling water enters at 30°C, it is not possible to condense acetic acid at 21°C with cooling water. This is why refrigerated water was used in the original design. 

Gas reservoirs are produced by expansion of the gas contained in the reservoir. The high compressibility of the gas relative to the water in the reservoir (either connate water or underlying aquifer) make the gas expansion the dominant drive mechanism. Relative to oil reservoirs, the material balance calculation for gas reservoirs is rather simple. A major challenge in gas field development is to ensure a long sustainable plateau (typically 10 years) to attain a good sales price for the gas the customer usually requires a reliable supply of gas at an agreed rate over many years. The recovery factor for gas reservoirs depends upon how low the abandonment pressure can be reduced, which is why compression facilities are often provided on surface. Typical recovery factors are In the range 50 to 80 percent. 

The recovery factors for oil reservoirs mentioned in the previous section varied from 5 to 70 percent, depending on the drive meohanism. The explanation as to why the other 95 to 30 percent remains in the reservoir is not only due to the abandonment necessitated by lack of reservoir pressure or high water cuts, but also to the displacement of oil in the reservoir. 

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