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 Immigration Act of 1924 created a permanent quota system (that of 1921 was only temporary), reducing the 1921 annual quota from 358,000 to 164,000. In addition, the Act reduced the immigration limit from 3 percent to 2 percent of each foreign-born group living in the United States in 1890.