Specific Heat Capacity

Chu Wei Xiang (3S311)

Kenneth Tan (3S209)

Tan Yu Yang (3S323)

Specific Heat Capacity

• The amount of heat energy required to raise the temperature of a unit mass (of the body) by one degree, without going through a change in state

Specific Heat Capacity

c = Q

m × ∆T

Specific heat capacity (in Jkg-1K-1 or Jkg-1 °C -1 )

Heat or thermal energy absorbed or released (in J)

Change in temperature (final temperature – initial temperature) [in K or °C]

Mass of the substance (in kg)

Specific heat capacity

• Larger amount of heat energy is required to raise the temperature of a substance with high specific heat capacity than one with low specific heat capacity.

• The specific heat of almost any substance can be measured, these includes chemical elements, compounds, alloys, solutions etc.

• Impurities: • For alloys, small impurity concentrations

can greatly affect the specific heat. • Alloys may display difference in behavior

even when small amounts of impurities are present on one element of the alloy.

Factor affecting specific heat capacity

Specific heat capacity and heat capacity

• Temperature of an object is a measure of its random molecular motions.

• Temperature increases as the average speed of the atoms or molecules increases.

• Different materials have different specific heat capacity because different types of molecules and atoms need different amounts of energy to raise their speed.

Specific heat capacity and heat capacity

• For the similar material, a larger object will have a larger heat capacity• More molecules that must move faster

to increase the temperature. • Therefore they need more thermal

energy to raise the temperature.

List of specific heat capacities

Substance c in J/gm Kc in cal/gm K orBtu/lb F

Molar CJ/mol K

Aluminum 0.900 0.215 24.3

Bismuth 0.123 0.0294 25.7

Copper 0.386 0.0923 24.5

Brass 0.380 0.092 ...

Gold 0.126 0.0301 25.6

Lead 0.128 0.0305 26.4

Silver 0.233 0.0558 24.9

Tungsten 0.134 0.0321 24.8

Zinc 0.387 0.0925 25.2

Mercury 0.140 0.033 28.3

Alcohol(ethyl) 2.4 0.58 111

Water 4.186 1.00 75.2

Ice (-10 C) 2.05 0.49 36.9

Granite .790 0.19 ...

Glass .84 0.20 ...

Specific Heat Capacity and Heat exchanger

If the fluid passing through the pipes is to be

warmed: Fluid to be warmed: low SHC Fluid used to warm: low SHC Pipes (fluid to be warmed passes through):

low SHC

References:

• http://www.lifetime-reliability.com/Training/TGT001%20Heat%20exchanger%20basics.pdf

• http://hyperphysics.phy-astr.gsu.edu/HBASE/thermo/spht.html#c2• http://www.economicexpert.com/a/Joule:per:kilogram:kelvin.htm• http://dic.academic.ru/dic.nsf/enwiki/17444• http://physics.suite101.com/article.cfm/specific_heat_capacity• http://www.absoluteastronomy.com/topics/Specific_heat_capacity• http://books.google.com.sg/books?id=SE-

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