The student hopes these samples are gold which has a density of 19.3 g/cm 3. A local geologist suggested that samples might be pyrite which is a mineral with a density of 5.01 g/cm 3. What is the identity of the unknown sample?

indium, and thallium have three electrons i think

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.

the ratio of the conjugate base to the acid required to attain the desired ph.