Coolant solutions

The question asks for the freezing point of a solution. The phrase to prevent the waterfrom freezing reveals that we are dealing with depression of the freezing point of water. Equation describes this process for a dilute solution A Zf —. A coolant solution is quite concentrated, so this equation... 

C12-0064. Ethylene glycol, an automobile coolant, has the chemical formula HOCH2 CH2 OH. Calculate the vapor pressure of water above a coolant solution containing 65.0 g of ethylene glycol dissolved in 0.500 L of water (density = 1.00 g/mL), at 100 °C, the boiling point of pure water. 

Contact of aqueous ethylene glycol solutions with d.c.-energised silvered copper wires causes ignition of the latter. Bare copper or nickel- or tin-plated wires were inert and silver-plated wire can be made so by adding benzotriazole as a metal deactivator to the coolant solution [1], This problem of electrical connector fires in aircraft has been studied in detail to identify the significant factors [2],... 

Beakers and Flasks. Beakers and flasks are the least effective containers for cryogenic materials because there is no insulation whatsoever. However, if the coolant is only water, ice, or a salt/ice mixture, not much insulation is required. There is little concern for rapid material loss with these coolant solutions because they are easy and inexpensive to replace. In addition, it is (usually) safe to pick up these containers with your bare hands. If any ice forms on the sides of a container, it is simple to use gloves or tongs to pick up the beaker or flask and prevent possible skin damage. 

A convenient and inexpensive unit for continuous operation can easily be made by stripping the compressor and cooling coils from an old refrigerator and immersing the cooling coils in the coolant solution. 

After 32 days at 88°C in 33% Prestone II (a commercial engine coolant solution that contains silicate inhibitors), ZA-8 and Alloy 3, either as-cast or polished, showed no corrosion. Dynamic tests confirmed the suitability of ZA-8 at 118°C. ZA-27 displayed intergranular attack when tested as-cast but not when its surface was polished before testing. Possibly, the soft, zinc-rich phase had been smeared over the whole surface during polishing. 

In severe accidents in PWR s, the availability of boric acid vapor and aerosols for reactions with CsOH and Csl depends on the particular accident sequence (see Section 7.3.2.3.I.). These reactions are of greater signiflcance in the high-pressure accident sequence, since in this case the boric acid inventory of the primary coolant and the emergency coolant solutions becomes concentrated in the residual water volume inside the reactor pressure vessel because of the considerable volatility of boric acid at a pressure of 16 MPa, this compound will be partly volatilized with the steam. In contrast, in low-pressure accident sequences most of the primary coolant boric acid inventory will be ejected during blowdown and, thus, not be... 

Sump water pH is the most important parameter for controlling the iodine partition coefficient, as was discussed in the preceding section. When the sump water is merely composed of the primary coolant and the emergency core coolant solutions (boric acid solution), a pH on the order of 5.5 has to be expected. Addi-... 

Solutions are addressed specifically and in more detail in Chapter 7. At this point, however, it is useful to have some imderstanding of the quantitative expression of the amount of solute dissolved in a specified amount of solution. In a relative sense, a solution that has comparatively little solute dissolved per unit volume of solution is called a dilute solution, whereas one with an amount of solute of the same order of magnitude as that of the solvent is a concentrated solution. Water saturated with air at 25 °C contains only about 8 milligrams of oxygen dissolved in 1 liter of water this composes a dilute solution of oxygen. A typical engine coolant solution contains about as much ethylene glycol (antifreeze) as it does water, so it is a concentrated solution. A solution that is at equilibrium with excess solute so that it contains the maximum amount of solute that it can dissolve is called a saturated solution. One that can still dissolve more solute is called an unsaturated solution. 

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