What were the main differences and consequences between the first and second Opium Wars? In what sense did either of these wars show that China was under the oppression of the British imperialism?

The main differences between the First and Second Opium Wars are seen in the outcomes of the wars. The Opium Wars began because of trade disputes between Britain and the Qing Empire of China. Chinese goods such as silk and porcelain were in high demand in Britain and the rest of Europe. In addition to spending large sums of silver on Chinese goods, British trade was confined to one port in China, Canton, which allowed Chinese authorities to control trade. The British East India Company started selling opium from India to China in order to offset the trade imbalance and make more money. Many in China soon became addicted to Opium, angering Chinese officials—especially since the British Empire had outlawed opium.
When the Qing outlawed opium and banned the opium trade, the British sent naval and military forces to China. In 1842, after suffering a series of defeats by the British, the Chinese were forced to sign the Treaty of Nanking. Under this treaty, the British were granted special trade rights in China, which granted the British the control of Hong Kong and opened five additional ports to British trade, meaning they were no longer confined to trading solely out of Canton.
The British were not satisfied with these agreements, however, and the Second Opium War began in 1857. During this war, France, Russia, and the United States joined the British in fighting the Chinese in order to gain their own trade rights and secure rights for Christian missionaries they sent to China. In 1860 at the Convention of Peking, Christians were given full civil rights, the city of Tianjin was opened, the No. 1 District of Kowloon was ceded to Britain, and freedom of religion was granted in China. It was also agreed that British ships would be allowed to carry indentured Chinese to the Americas, that China would pay Britain and France each 8 million taels, and that the opium trade would be legalized. As with the First Opium War, European military technology left the Chinese at the mercy of Western demands for free trade and spheres of influence.