Page 186 - Chemistry ICSE Class IX

174 ICSE Chemistry – 9
Relationship between Kelvin Scale and Celsius Scale

of Temperature

How are the temperatures on Kelvin and Celsius scales
related to each other
The Kelvin scale of temperature is also called the absolute temperature
scale.
ƒ For Kelvin scale, the lower xed point (ice point) is taken as 273.15 K
and the upper xed point (steam point) is 373.15 K. The
temperature range between the lower xed point and the
upper xed point is divided into 100 (= 373.15 – 273.15)
divisions. So, on Kelvin scale, each division corresponds to
1 K.
ƒ For Celsius scale, the lower xed point (ice point) is taken
as 0°C, and the upper xed point (steam point) is 100°C.
The temperature range between the lower and the upper
xed points is divided into 100 (= 100 – 0) divisions. So, on
Celsius scale, each division corresponds to 1°C.
Thus, the size of one degree on the Celsius scale and the
Kelvin scale is equal, i.e.,
Fig. 7.8 A comparison of the Kelvin and Celsius
temperature scales (not to the scale) 1°C = 1 K
The temperature on the Kelvin scale can, therefore, be
obtained from the Celsius temperature by using the relationship,
Temperature on Kelvin scale = Temperature on Celsius scale + 273.15
or K = C + 273.15
One can also write,
C = K – 273.15
tŚŝůĞ ĚĞƐĐƌŝďŝŶŐ ƚĞŵƉĞƌĂƚƵƌĞ ŽŶ ƚŚĞ If C and K are the temperatures of a body on the Celsius and Kelvin
<ĞůǀŝŶ ƐĐĂůĞ͕ ƚŚĞ ƐŝŐŶ ŽĨ ĚĞŐƌĞĞ;ΣͿ ŝƐ scales respectively, then
ŶŽƚ ƵƐĞĚ͘ &Žƌ ĞdžĂŵƉůĞ͕
Ϯϳϯ͘ϭϱ < ; ŽƌƌĞĐƚͿ C = K – 273.15 (7.11)
Ϯϳϯ͘ϭϱ Σ< ;tƌŽŶŐͿ 100 100
A comparison of the two temperature scales is shown in Fig. 7.8.
ASSIGNMENT 2

Charles’ law and the absolute temperature scale, Relationship between Kelvin and Celsius scales.

ϭ͘ ^ƚĂƚĞ ƚŚĞ ŚĂƌůĞƐ͛ ůĂǁ͘
Ϯ͘ ƌĂǁ Ă ǀŽůƵŵĞ vs ƚĞŵƉĞƌĂƚƵƌĞ ;Σ Ϳ ŐƌĂƉŚ ĨŽƌ Ă ŐĂƐ ŚĞůĚ ƵŶĚĞƌ ĐŽŶƐƚĂŶƚ ƉƌĞƐƐƵƌĞ͘
ϯ͘ tŚĂƚ ƚĞŵƉĞƌĂƚƵƌĞ ĐŽƌƌĞƐƉŽŶĚƐ ƚŽ njĞƌŽ ǀŽůƵŵĞ ŽĨ Ă ŐĂƐ͍
ϰ͘ /ůůƵƐƚƌĂƚĞ ƚŚĞ ŚĂƌůĞƐ͛ ůĂǁ ďLJ ĚƌĂǁŝŶŐ Ă ŐƌĂƉŚ ďĞƚǁĞĞŶ ǀŽůƵŵĞ ĂŶĚ ĂďƐŽůƵƚĞ ƚĞŵƉĞƌĂƚƵƌĞ͘
ϱ͘ hƐŝŶŐ ƚŚĞ ŚĂƌůĞƐ͛ ůĂǁ ĞƋƵĂƟŽŶ͕ ƐŚŽǁ ƚŚĂƚ Ăƚ ĂďƐŽůƵƚĞ njĞƌŽ ĚĞŐƌĞĞ͕ ǀŽůƵŵĞ ŽĨ ĂŶLJ ŐĂƐ ƐĂŵƉůĞ ďĞĐŽŵĞƐ njĞƌŽ͘
ϲ͘ ,Žǁ ĂƌĞ ƚŚĞ ƚĞŵƉĞƌĂƚƵƌĞƐ ŽŶ <ĞůǀŝŶ ĂŶĚ ĞůƐŝƵƐ ƐĐĂůĞƐ ƌĞůĂƚĞĚ ƚŽ ĞĂĐŚ ŽƚŚĞƌ͍
Ideal Gas Equation

What is an ideal gas equation
Gases obeying the Boyle’s and Charles’ laws are termed as ideal gases. A
mathematical expression describing the simultaneous effect of changes in