[Chemistry Class Notes] on Celsius to Kelvin Conversion Pdf for Exam

We can measure temperature with the help of three different scales, which are Celsius, Kelvin, and Fahrenheit scales. The Celsius scale is also called a Centigrade scale sometimes, however, it is outdated. The Celsius scale is defined by an international agreement in regards to two fixed points, the stream point, and the ice point. The temperature of the stream point is defined as 100° Celsius while that of the ice point is defined as 0° Celsius. 

Kelvin is the fraction 1/273.16 of the thermodynamic temperature of water’s triple point. The unit of the thermodynamic temperature scale is known as the Kelvin. Today we will learn how to convert degrees Celsius into Kelvin and the formula to convert Celsius to Kelvin.

Absolute Temperature

It is known that the universe has a minimum temperature, however, it is not obvious until there is a better Physical temperature interpretation. Several experiments measure the pressure against temperature keeping the volume and mass constant. They tend to show the same results. Generally, the pressure-temperature graphs of different gasses show different slopes, however, they conclude to the same temperature at zero pressure just like the volume-temperature graphs did at zero volume. The smallest possible pressure is zero, therefore, the temperature intercept is the minimum temperature that is possible. This is referred to as the absolute zero.

The Kelvin scale is dependent on these experiments. However, it is not arbitrary but is designed in a way that the zero point is the absolute zero.

0K = – 273.15°C = -459.67°F

Kelvin, denoted by K, is known as the official metric unit for temperature. You would see here that there is no degree sign used with the Kelvin scale. For example, 2K is known as two Kelvin. 

Given below is the Celsius to Kelvin conversion formula.

T = TC  + 273.15

Similarly, the Kelvin to Celsius conversion formula is,

TC  = T –  273.15

The Kelvin temperature scale is designed in a way that one degree Celsius and one Kelvin equal the same.

Celsius to Kelvin Conversion Factor

Let us learn how to convert a degree into Kelvin and other conversion formulas.

1. Degree Celsius to Kelvin

K = C + 273.15

2. Degree Celsius to Degree Fahrenheit

F = 9/5 C + 32

3. Degree Fahrenheit to Degree Celsius

C = 5/9 F – 32

4. Degree Fahrenheit to Kelvin

K = 5/9 F + 459.67

5. Degree Fahrenheit to Rankin

R = F + 459.67

6. Degree Rankin to Kelvin

K = 5/9 R

Units of SI System

1. The basic unit of temperature according to the SI system is Kelvin. However, it can turn out to be impractical in several cases.

2. The Celsius scale of temperature, on the other hand, is often used in the clinical laboratory. Both the Celsius and Kelvin scales are related to one another closely and the conversion formula for Celsius to Kelvin scales is simple since both the units are equal to each other in magnitude.

3. The only difference between the Celsius and Kelvin scales is the zero point. The zero points on the Celsius scale refers to the freezing point of water. On the other hand, the zero points on the Kelvin scale refers to the theoretical temperature at no heat loss further, which is the absolute zero. However, the magnitude of the degree is the same on both scales. 

Celsius to Kelvin Formula

Let us learn about how to convert Celsius to Kelvin formula.

Water freezes at 0 degrees Celsius, which equals 273 Kelvin. Also, 0 Kelvin is equal to -273 degrees Celsius. Hence, to convert the degree to Kelvin, add 273 to the Celsius degree. And for converting Kelvin to Celsius, simply subtract 273.

K = °C + 273

°C = K – 273

The table below gives a comparative reading of all the three temperature scales having common reference points.

Let us take a look at how to change the temperature from Celsius to Kelvin with the help of an example.

Solved Example

The boiling point of ethyl alcohol is 78.5°C and its freezing point is -117°C at 1 atm pressure. Determine these temperatures at the Kelvin scale.

Solution:

To convert a degree Celsius to Kelvin,

K = °C + 273

Hence, the boiling point is

= 78.5 + 273.15 

= 351.7 K

Similarly, the freezing point is

= -117 + 273.15 

= 156K

Temperature

When we touch any material we feel either hotness or coldness in that object. Imagine we have to express the same feeling in the scientific community, the same object at the same temperature might feel hot to some and cold to some other. In order to solve this we need to have some measurement of the feeling which can be documented and will be absolute irrespective of the person explaining. 

The same measurement of hotness or coldness of any material is known as “Temperature”. Some others express temperature as the manifestation of thermal energy. When a Material is hot or cold it has the ability to either radiate or absorb heat/thermal energy. That ability can also be denoted by temperature.

As we have different units of measurement of length and mass, the same is the case with temperature. We will learn about two of those units of temperature namely Celcius and Kelvin.

Celcius

Celsius is also known as °(degree) Celcius is one of the widely used temperature units. The scale of measurement of Celsius is known as Celsius scale which was renamed after Swedish astronomer Anders Celsius. Prior to that the scale was known as the Centigrade scale which got its name from the Greek words Centi meaning 100 and Gradus meaning steps. The scale got its name from the 100 ° (measurement unit) difference between freezing and boiling point of water.

The Symbol used to denote it is ° C.

The Celsius is the SI derived unit of temperature measurement and used widely around the world.

Kelvin

Like Celsius, Kelvin is the fundamental unit of the Kelvin scale for Temperature measurement. The symbol used to denote it is K. 

As we know if we heat the gasses the volume will increase and if we cool the gas the volume will decrease. There will be an imaginary point where the temperature will be so low that the volume will become zero. That theoretical point is called absolute zero temperature. This point denotes the zero point on the Kelvin scale.

Kelvin vs Celsius

The difference in boiling and freezing temperatures of water is 100° in both Kelvin and Celsius scale which confirm 1°C is equal to 1K.

But both scales have different zero points.

Zero point on Celsius is the freezing point of water whereas zero point on the Kelvin scale is absolute zero temperature.

So if we relate both by using below 

Absolute zero temperature =  -273.15°C

=> 0K = -273.15°C

So as a conversion from Kelvin to degree Celsius we have to subtract 273.15 from the temperature and to convert from Celcius to Kelvin we need to add 273.15 to the temperature. Other than this various digital applications are available to convert different measurement units of temperature into any other unit. Using these online calculators help us to get accurate measurements within no time.