Essays /

15 Thermodynmics 250 272 Final Essay

Essay preview

THERMODYNAMICS
Synopsis:
1.

Thermodynamics deals with the relation between heat energy and other forms of energy.

2.

The thermodynamics coordinates of a system which are also called state variables are pressure, volume and temperature which are inter dependent.

3.

The temperature of a system can be expressed as a function of pressure and volume is f(P, V)=T.

Calorimetry:
4.

Calorimetery is the study of the measurement of quantities of heat.

5.

Quantity of heat is the amount of molecular energy stored in a body.

6.

Calorie : The quantity of heat required by one gram of water to raise its temperature from 14.5°C to 15.5°C is called one calorie.

7.

British Thermal Unit : The amount of heat required by 1 Pound of water to raise its temperature by 1°F is called one British thermal unit.

8.

Pound calorie : The amount of heat required by
1 Pound of water to raise its temperature by 1°C is called one pound calorie. 1 pound calorie=453.6 calories
1 calorie=4.186 joule

Heat Capacity :
9.

The amount of heat required to produce a specified change of temperature is directly proportional to the mass of the material.

10. For a given mass of material, the amount of heat absorbed is directly proportional to the temperature increase.
11. The amount of heat required to raise the temperature of the whole body by 1°C is called heat capacity or thermal capacity. Unit is J/K or Cal/°C.
dQ
C=
dT

12. Specific heat : The quantity of heat required by one gram of a substance to raise its temperature by 1°C is called its specific heat.
or
Heat capacity per unit mass. Unit is J/Kg-K or Cal/g-°C.
dQ
s=
mdT
dQ = msdT
13. If m is the mass and s is the specific heat of the material of the body, then the thermal capacity = ms cal/°C.
14. Of all solids and liquids, water has the highest specific heat or specific heat capacity. The value is 1 cal/g/°C or 4200 J/kg/K.
15. The specific heat of lead is the least among solids. (i.e., 0.03 cal/g/°C) 16. In liquids, mercury has least specific heat.
1

17. Of all solids, liquids and gases, hydrogen has the highest specific heat. It is equal to 3.5 cal/g/°C. 18. Specific heat depends upon the nature of the substance and does not depend upon mass, volume and heat supplied.

19. Specific heat of copper

= 0.1 cal/g/°C.

Specific heat of ice

= 0.5 cal/g/°C

Specific heat of steam

= 0.45 cal/g/°C

Specific heat of lead

= 0.03 cal/g/°C.

20. Specific heat of a solid at its melting point is infinite. 21. Specific heat of a liquid at its boiling point is infinite. 22. The water equivalent of a body is the number of grams of water which require the same amount of heat as the substance for the same rise of temperature. Unit is grams. Water equivalent=ms grams.

23. Water equivalent is numerically equal to heat capacity.
24. Latent heat (L) is the quantity of heat required by unit mass of a substance to change its state at a constant temperature. Unit of L is cal/g or J/kg.
25. Latent heat of fusion is the quantity of heat required by unit mass of a solid to melt it at its melting point.
26. The latent heat of ice is 80 cal/g or 3.35x105 J/kg.
27. Latent heat of vapourisation is the quantity of heat required by unit mass of a liquid to vapourise it at its boiling point.
28. The latent heat of steam is 540 cal/g or 2.26x106 J/kg.
29. Latent heat of vapourisation of water decreases with the increase of pressure (i.e., increase of boiling point).
30. The latent heat of steam at boiling point t is given by L=600−0.06t. 31. Latent heat of vapourisation decreases with increase in temperature. 32. Latent heat of a substance becomes zero at critical temperature. 33. Latent heat depends on the nature of a substance and pressure. 34. During the change of state, the formula used to calculate the heat lost or heat gained is Q = mL. 35. When one gram of steam at 100°C is mixed with one gram of ice at 0...

Read more

Keywords

0 0.00750 0.03 0.06 0.1 0.45 0.459 0.5 1 1.33 1.4 1.67 1/3 10 100 101 102 103 104 105 106 107 108 109 11 110 111 112 113 114 115 116 117 118 119 12 120 121 122 123 124 125 126 127 128 129 13 130 131 132 14 14.5 15 15.5 16 17 18 19 2 2.26 2.303 20 21 22 23 24 25 250 26 27 272 273.16 28 29 2js 3 3.35 3.5 30 31 32 33 34 35 36 37 38 39 3r 4 4.186 4.58 40 41 4186 42 4200 43 44 45 453.6 46 47 48 49 4r 5 50 51 52 53 54 540 55 56 57 58 59 6 60 600 61 613.10 62 63 64 65 66 67 68 69 7 70 71 72 73 74 75 76 77 78 79 8 8.3 80 81 82 83 84 85 86 87 88 89 9 90 91 92 93 94 95 96 97 98 99 ab absent absolut absorb act adiabat agenc allow along also alway among amount anoth area arrang atmospher atom attain b back bad ball base bc becom bell blim block bodi boil bomb bounc boyl british bullet burn burnt c cal cal/g cal/g- calcul call calori calorif calorimet calorimeteri calorimetri cannot capac carnot carri caus cd chang classius clear cm co co-effici co-exist coeffici coexist cold colder combin combust complet compon composit compress compressor condens conduct conductor configur consist constant construct content contract convert cool coolant coordin copper cp cp/cv critic curv cv cycl cyclic cylind d da deal decreas denot depend determin develop devic diagram diatom diesel differ differenti direct dissip distanc done dp dq drag drawn drop dt du due dv dw e ea effect effici efficienti elast electr enclos energi engin equal equat equilibrium equival erg/cal essenti ex exist expand expans express extern extinguish f factor fall final fire first fit fix flow follow food forc form formula four fraction free friction frictionless frost fuel function fusion g gain gas gase general gh give given go good gram graph greater ground h h1 h2 heat heavi height henc hg high higher highest hoar hoar-frost horizont hot hotter hydrogen hypothesi i.e ice ideal ident ii iii imagin imposs increas independ infinit initi insul inter intermolecular intern isobar isochor isotherm iv j j/cal j/k j/kcal j/kg j/kg-k j/kg/k j/mol-k jh jl joul joule/calorie js k k.e kelvin known l larg largest last latent law lead least less liber lie lin line liquid ln lost low lower lowest m m1 m1s1 m2 m2s2 m3 machin made maintain mani mass materi matter maximum may mayer mdt measur mechan melt mercuri metal method minimum mix mixtru mixtur ml mm mole molecul molecular monoatom motion move ms msdt mst msδθ mv n n1 n1c n1cp1 n2 n2cp2 name natur nc negat net non non-differenti none nr nrt1 nrt2 nuclear number numer obey obstacl obtain one oper opposit otherwis otto outsid p p.e p1 p1v1 p2 p2v2 p3v3 p4v4 pa pb per perfect perform phase piston place point polyatom posit possibl potenti pound prefer pressur principl process produc proport pump pv pvγ q q1 q2 qn quantiti quick r r/j radiat rais rate ratio reactor real reason refriger reject relat remain remov repres requir respect result retain return revers rise root rough rtlog10 s.no s1 s2 s3 sampl second self seri serv show shown si sign sinc sink sl slight slope slow slowli solid sourc specif specifi st stand state statement steam step stop store studi stuff su substanc suppli surfac surround synopsi system t1 t2 t3 take temperatur theorem thermal thermodynam thermodynm three tight time tn total transfer tri tripl tvγ two type unaid undergo unit univers upon use utilis v v1 v2 v4 valu vapour vapouris variabl ve veloc vessel vi vii viii volum w w1 w2 w3 w4 wall warm water way whatev whole without work workdon x x105 x106 x107 y zero α β γ γ1 γp γtγ δp δv δw δθ η μ μgd μmgd