Question

Nante: Physics 06-05 Phase Change and Latent Heat Phase Change is required to (or released by changing the Lakeside bonds in of matter • Heat always the • Phases of matter of a material Solid taon 2016 Liquid Gas • Top arrows energy • Bottom arrows energy When you cook pasta (or anything that Table 14 2 Heats of Fusion and Vaportation 14 requires boiling is it better to have a vigorous boil or to turn down the heat to produce barely boiling water? Substance Melting point) kg kcal/kg Boiling point ("C) kW/kg kcal/kg Helum 5.23 -260.7 20.9 1.25 -268.9 4.99 Hydrogen -250.3 8.6 14.0 -252.9 108 452 Nitrogen -2100 25.5 6.09 - 1958 201 48.0 Oxygen -218.8 13.8 3.30 -1630 213 50.9 Ethanol -114 104 24.9 783 854204 Ammonia - 75 1 08 -334 1370 327 • The amount of Mercury 1-38.9 118 282357 2 72 65.0 required to change War 0. 00 3 34 798 1000 22505394 Sulfur 119 3 8.1 9.10 4446 326 77.9 OML 327 5.85 . 24.5 1750 O 208 871 heat required; m - mass; L- Antimony 1631 latent heat 1 6539.4 1440 561 134 Latent heat of fusion (L) Aluminum 650 90 2450 11400 2720 • Refers to change between Silver 961 383 21. 1 2193 2336 558 and Gold 1063 64.5 15.4 2660 1578 377 Latent heat of vaporization (L.) Copper 1083 134 32.0 2595 5000 1211 • Refers to change between Uranum 1123 0 420 2000 1900 454 Tungsten 3410 184 44 5 000 Latent heat of sublimation (L.) 4610 1150 • Refers to change between You have a glass of 1 kg warm water (25°C). To make it cold you put in some ice cubes (-5°C). After an equilibrium temperature is reached, there is a little ice left. What is the minimum mass of the ice cubes? (Assume no heat is lost to the environment.) and
please answer all

Answer 1

* Energy is required to change in the cohesive force in molecules of matter.

* Tip arrows released energy, bottom arrows absorbed energy.

When you cook you need to maintain a constant heating below boiling point.vigorous heating evopartes the water, not useful cook the food.

* The amount heat energy per unit mass required to change the state is called Latent heat.

* Latent heat of fusion refers to change of state from solid to liquid.

*Latent heat of Vaporization refers to change of state from liquid to gas.

* Latent heat of sublimation refers to change of state from solid to gas.

libe mass in water m= 1kg = 1000 g prafic heat, so I callao temp difference, Dt = 25-0 = 25°c on theat liberated Aa=msat = 1000x1125=25000 cal Let mass of ice, Mice Specific hat, sice call go temperature to be raised, at = 5°C Heat required sa = msat = mice ² x 5 Heat required to mett, AQ = mice 46 = mica80 [:2 Soal ! Total Heat required, Aga Mice + 80 mice 25000 = mice [ 30 + 6/8] = 165 mice 25ooo x 2 minimum mass of ice require, mice- 165 = 303g =0.303kg