Compounds that have the same molecular formula but different chemical structures are called isomers. Remember isomerism is a property between a pair (or more) of molecules, i.e. a molecule is an isomer of another molecule. A similar relationship is that of brother or sister...
Many Americans are up in arms. But in fact, keeping out desperate souls seeking entry into America has deep roots. On this day 100 years ago, the United States passed the strictest immigration law of its time: the Immigration Act of 1917. The law restricted the immigration of undesirables, including many people from the Middle East and Asia, through increased taxes, tests and outright bans.
The act excluded Chinese laborers from immigrating to the United States for ten years and was the first immigration law passed by Congress. Laborers in the United States and laborers with work visas received a certificate of residency and were allowed to travel in and out of the United States. literacy requirement was added in the Immigration Act of 1917. In 1921 the United States Congress passed the Emergency Quota Act, which established national immigration quotas. The quotas were based on the number of foreign-born residents of each nationality who were living in the United States as of the 1910 census.