An average copper penny minted in the 1960s contained about 3.000 g of copper. how much chalcopyrite had be mined to produce 100 pennies?

To know the answer, determine first the mass of the copper used:

Copper used = 100 pennies x 3.0g Cu per penny = 300.0 g Cu 

then, determine the pathway and molar ratio from Cu formed back to CuFeS2 required using the balanced reactions:

1 Cu2S from 2 CuS; 2Cu from 1 Cu2S; 2CuS from 2CuFeS2 
Therefore 2Cu from 2CuFeS2, they are in a one to one molar ratio. 

then, convert g Cu to moles and g of CuFeS2:
= 300.0 g Cu * 1 mol Cu/63.546g Cu * 2 mol CuFeS2/2 moles Cu

= 4.72 moles CuFeS2 

chalcopyrite had to be mined = 4.72 moles CuFeS2 * 183.54 g CuFeS2/1 mole CuFeS2 = 866.49 g CuFeS2

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.