Water heating curve

Fig. 3. Flame hardening (a) tempeiatuie—time heating curves of a 25 x 50 x 100 mm specimen at a feed of 75 mm /min and burner distance of 8 mm showing temperatures of A, surface B, 2 mm below surface and C, 10 mm below surface (b) hardness—depth curves for a 0.50% C steel 25 X 75 X 100 mm specimen at a feed of 50 mm /min, temperatures ia °C measured 10 mm below the surface, and burner distances ia mm, respectively, of A, 530 and 50 B, 540 and 12 C, 545 and 10 D, 550 and 8 and E, 565 and 6. Flame heating followed by water spray quenching. HV = Vickers hardness.

Flo. 8. Temperature distribution in a once-through boiler tube [from Schmidt (S3)]. L = 98.5 in., d= 0.197 in., P = 2415 psia, AA = 365 Btu/lb, G=0.44xl06 lb/hr-ft2. Curve 1 water temperature. Curve 2 tube-wall temperature with heat flux of 92 x 103 Btu/hr-ft2. Curve 3 tube-wall temperature with heat flux of 148 x 103 Btu/hr-ft2. Curve 4 tube-wall temperature with heat flux of 221 x 103 Btu/hr-ft2. 

Sulphate. Melamine sulphate eliminates the water of crystallisation on heating between 100 - 230 0 as shown by TG, DTG and water evolution curves of Figure 10 (1st step). The amount of water evolved corresponds to one molecule per molecule of salt (calculated weight loss 7.4% experimental 8%). The IR of the anhydrous salt is shown in Figure 11A in which the typical strong band of sulphate anion group at 1095 cm-1 is evident. 

Using your textbook, look up the heating curve for water. Describe each portion of the curve and explain why it has that particular shape. 

Figure 10.2 shows the heating curve for water. To understand Figure 10.2, the path of an ice cube on the curve is followed as heat is supplied to it. To make our example realistic, assume the ice cube has a mass of 10 grams and is taken out of a freezer where its temperature is — 10°C. Consider what happens when the cube is placed in a pan on a stove and heat applied. Initially, the ice cube is at — 10°C when it is removed from the freezer. The temperature of the ice cube... 

Figure 7.9 Softening curves for rheological parameters in water heating.

Fig. 2. Isosteric heat curves for the adsorption of water on two similar mont-morillonite clay samples. (A) From heat-of-immersion data of Ref. SO (B) From adsorption data of Ref. St.

Extract inner test tube 1 with the crystals from outer tube 6 and immerse it directly into the water in the beaker. When part of the crystals melt and the reaction substance is a liquid, wipe tube 1 outside and return it into tube 6 immersed into the beaker with water. Begin to record the readings of the thermometer in test tube 1 every 30 seconds with constant stirring of the tube contents. Why does the temperature stop rising Terminate this part of the experiment when the temperature of the reaction mixture rises to 34-35 °C. Draw a heating curve of the temperature against the time. 

Dissolve about 250 g. of commercial sodium sulfate (Glauber s salt) in 800 cc. of water heated to 35°. (Look up the solubility curve of sodium sulfate to find the explanation for this Sp3 direction.) If the salt is notably impure, the solution should be freed from iron by adding enough bromine water to oxidize the iron and then enough sodium hydroxide to make the solution distinctly alkaline. 

FIGURE 10.10 A heating curve for H20, showing the temperature changes and phase transitions that occur when heat is added. The plateau at 0°C represents the melting of solid ice, and the plateau at 100°C represents the boiling of liquid water. 

Draw a molar heating curve for ethanol, C2H5OH, similar to that shown for water in Figure 10.10. Begin with solid ethanol at its melting point, and raise the temperature to 100°C. The necessary data are given in Problem 10.51. 

If a time graph was made a pure substance being heated or cooled, it would look something like the following graph for the heating of water and be called a heating curve for water. 

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