What act prohibited the us from selling or giving weapons to any nation at war and had time limit of six months?

The act you're referring to is the Neutrality Act of 1935. This legislation prohibited the sale or transfer of arms and munitions to nations at war and included a provision for a six-month time limit on its restrictions. The aim was to keep the United States out of international conflicts and maintain a stance of neutrality during the rising tensions in Europe. Subsequent Neutrality Acts were passed in later years, each addressing the changing geopolitical landscape.