Answer :

Gibbs
The Chinese agreed to sign the Treaty of Nanjing which signified the end of the First Opium War in 1842 because of the potential for an even greater defeat through battle. The major goal of the treaty was to open up trade in China to the British which the British gained from the weakened Chinese Government. 

The things that China Agree to do once the Treaty of Nanjing was signed are:  

-create a "fair and reasonable" tariff

-allow Britain to trade at five ports

-surrender the territory of Hong Kon

Explanation:

Treaty of Nanjing, (August 29, 1842) treaty that closed the first Opium War, the first of the complex treaties among China and outer imperialist powers. China paid the British a compensation, ceded the territory of Hong Kong, and granted to build a “fair and equitable” tariff.