Latent Heat

Discussion

discussion

Name the 6 major phase changes (including synonyms).

Heat absorbed or released as the result of a phase change is called latent heat. There is no temperature change during a phase change, thus there is no change in the kinetic energy of the particles in the material. The energy released comes from the potential energy stored in the bonds between the particles.

Q = mL

Scattered thoughts …

elements Tm (℃) Tb (℃) Lf (kJ/kg) Lv (kJ/kg)
aluminum 660 2519 397 10,900
argon −189 −186 29.5 161
bismuth 271 1564 54.0 723
bromine (Br2) −7 59 132 375
chlorine (Cl2) −102 −34 181 576
copper 1084 2562 209 4730
gold 1064 2856 63.7 1645
helium n/a −269 3.45 20.7
hydrogen (H2) −259 −253 59.5 445
iron 1538 2861 247 6090
krypton -157 -153 16.3 108
lead 327 1749 23.0 866
lithium 181 1342 432 21,200
mercury −39 357 11.4 295
neon −249 −246 16.8 84.8
nickel 1455 2913 298 6430
nitrogen (N2) −210 −196 25.3 199
oxygen (O2) −219 −183 13.7 213
plutonium (ε) 640 3228 11.6 1370
silicon 1414 3265 1790 12,800
silver 962 2162 105 2390
sodium 98 883 113 4240
sulfur 115 445 53.6 1400
tin 231 2602 59.2 2490
titanium 1668 3287 296 8880
tungsten 3422 5555 285 4390
uranium 1135 4131 38.4 1750
zinc 420 907 112 1890
compounds Tm (℃) Tb (℃) Lf (kJ/kg) Lv (kJ/kg)
alcohol, ethyl −130 78    
alcohol, methyl −97 64.7    
ammonia −77.7 −33.3    
butane −138.4 −0.5 80.2  
carbon dioxide n/a n/a 571 205
ethane −172 −89 95.1  
freon 12, −30 ℃ −158 −29.8   166.2
freon 12,  0 ℃ −158 −29.8   152.8
freon 12, +30 ℃ −158 −29.8   136.3
methane −182 −164 58.4 112
propane −188 −44.5 80.1  
water, 0 ℃ 0 100 334 2501
water, 25 ℃ 0 100   2441
water, 100 ℃ 0 100   2258
wax, beeswax 62      
foods Tm (℃) Tb (℃) Lf (kJ/kg) Lv (kJ/kg)
butter 32~35      
lard 41      
margarine, table 34~37      
margarine, bakery 38~43      
oil, cocoa butter 34      
oil, coconut 24      
oil, corn −20? −15?      
oil, olive −6      
oil, palm ~35      
oil, peanut 3      
oil, soya −16? −13?      
shortening, vegetable 44~50      
sugar, fructose 104      
sugar, glucose 146      
sugar, sucrose 186      
Normal phase change quantities for selected materials