I need help identifying how the infinitve phrase is used (parts of speech) in the following sentences! :

Rhode Island was the first colony in which the slaves were allowed to enlist in its army.
To enlist in the British army and to gain their freedom were the reasons thousands of other slaves left their plantations.
In 1781, twenty-six people of African descent helped to found the city of Los Angeles, California.
A new law to prohibit slavery from the Northwest Territory was passed by the Continental Congress.
Many people were unhappy to see that the U.S. Constitution protected slavery.
The U.S. Congress refused to accept a legal petition from African Americans in 1797.

Which ones do you know?

Post them, and we'll help you with the others.