Global warming

                         Global  warming 

Global warming is the rapid increase in earth's average surface temperature over the past contury primarily due to the  greenhouse gases released as people burn fossil fuels.

The global average surface Temperature rose 0.6 to 0.9 degree Celsius (1.1to 1.6) between 1906 and 2005 and the rate of temperature increasing has nearly doubled in last 50 years. Temperature are certain to go up further. Despite ups and downs from year to year. Global Global average surface temperature is rising. By the beginning of the 21st century earth's temperature was roughly 0.5 degree Celsius above the long term (1951-1980) average

 (NASA figure adapted from godd institure of space studies surface temperature analysis. 

      

Read More

Catalyst

                          Catalyst

In 1836 Bergillius absorbe that there are some substances which increases the rate of reaction without changing themselves. 

  

A catalyst is defined as a substance which change the rate of reaction without undergoing any change themselves and can be recovered. The phenomina of increasing the rate of reaction with the help of catalyst is called Catalysis. 

Catalyst is of two types-   

1. Positive Catalyst

 2. Negative Catalyst

1.Positive catalyst:-   the catalyst which increase the rate of reaction is called positive catalyst and the process is called positive catalysis. 

Example- 

      2kclo3 —––— 2kcl + 3O2

      4Hcl + 02—— 2H2O +2cl2

2. Negative catalyst:- the negative catalyst which decreases the rate of reactions is called negative catalyst and the phenomina is called Negative Catalysis. 

Example-

4CHcl3+302——4COcl2+                                      2H2O+2cl2

    

Read More