How many moles of gas is contained in 2.21 L at STP?​

its an helium gas are contained in a 4.0L at STP? 0.17

Explanation:

because the elements in column 2.21 is what quantity of gas in holes

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.