The percent yield for a chemical reaction can not be calculated until the reaction is completed
True
False

False

Explanation:

using the measurements of the amounts of chemicals, it can be calculated to some degree of accuracy depending mainly on the accuracy of the measurements and enviroments of the reaction

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.