Given the balanced equation representing a reaction: h2 → h h what occurs during this reaction? 1. energy is absorbed as bonds are formed. 2. energy is absorbed as bonds are broken. 3. energy is released as bonds are formed. 4. energy is released as bonds are broken.

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.