Jurchens are founders of the Qin kingdom that succeeded the Liao in northern China; annexed most of the Yellow River basin and forced Song to flee to the south.

No, the Chinese used gunpowder before the Mongols did. So did the Jurchens, who conquered northern China in the early 1100s. The Mongols undoubtedly acquired knowledge of gunpowder weapons from the Jurchens and the Chinese.

The very end of the 12th century.the 12th century is the period from 1101 to 1200 in accordance with the Julian calendar in the Christian/Common Era. In the history of European culture, this period is considered part of the High Middle Ages and is sometimes called the Age of the Cistercians. In Song Dynasty China an invasion by Jurchens causes a political schism of north and south. The Khmer Empire of Cambodia flourished during this century, while the Fatimids of Egypt were overtaken by the Ayyubid dynasty.

The Mongolians.

It rose from the fact that Genghis Khan (aka Temujin) began taking control of few Mongolian herders, then many more, then forming an army large enough to conquer the entirety of Mongolia. Then expanding into the territories of the Indigenous Siberian tribes, forcing them to accept Genghis Khan as their sovereign. Then Genghis Khan expanded his influence to the Jurchens in Manchuria. Then the Mongol Empire expanded to conquer much of Northern China and then expand west-wards towards Central Asia. Then the Mongols marched straight into Iran/Persia and Afghanistan/Bactria not without committing widespread genocide. When Ogedei took over as the Khan/Khagan, the Mongols conquered Korea, Russia, Hungary, the Caucasus, Romania and Poland. After Ogedei Khan's death, the Mongol Empire started splitting but the successor states such as the Ilkhanates, Golden Horde and Yuan Dynasty and Chagatai Khanate were all significantly powerful and continued to expand Genghis' legacy.