The actual amount of pure silver is .36169 of an ounce.
None, because the coin doesn't exist. JFK is on the HALF dollar. Please see the Related Question for more information.
No U.S. coins were pure silver - it's too soft. 10% copper was added to make them hard enough to resist wear.
None, it's made from copper-nickel.
No such coin exists that has been released for circulation. While some 1964 (D) silver (peace) dollars were minted, the all of them were melted shortly after being struck. There is however a Kennedy...