1. Certain agreements are considered void under contract law, such as agreements with minors, agreements due to mutual mistake, agreements with an unlawful object, and agreements in restraint of trade or marriage.
2. For an agreement to be valid and enforceable, the terms must be reasonably certain and precise, and performance must be possible.
3. Impossibility of performance may exist at the time of contracting, if the parties are aware performance is impossible, or may arise after contracting due to unforeseen circumstances, in which case the contract becomes void.