1)you have a glass of pure water. are chemical reactions occurring in the water ?if so, what are they?if not explain why not.

2)while investigation the effects of acid rain in your area, you discover a lake that is surprisingly resistant to changes in pH caused by acid rain. explain why the lake resists changes in pH.
3)A) one atmospheric compound is responsible(after it has dissolved in water)for both the general acidity of normal rainwater and the acidity of much soil. what is this compound?
B)is this compound put into the atmosphere solely by pollution?
C)why doesn't this compound cause seawater to become acidic?
D)if all of this compound were to vanish from the atmosphere, would humans benefit?why or why not ?

I am disturbed that you have posted seven(7) questions and made no effort to answer any of them.

#1. H2O + H2O <--> H3O^+ + OH^-

one atmospheric compound is responsible(after it has dissolved in water)for both the general acidity of normal rainwater and the acidity of much soil. what is this compound?

1) In a glass of pure water, chemical reactions can occur, albeit very slowly. Water itself can undergo a self-ionization reaction, where a small fraction of water molecules break apart into ions:

H2O ⇌ H+ + OH-

However, this reaction occurs to a very limited extent, with only a small number of water molecules forming ions at any given time. Hence, while chemical reactions are technically happening in the water, they are considered negligible.

2) The lake that is resistant to changes in pH caused by acid rain most likely has a buffering capacity. A buffer is a solution that can resist changes in pH when an acid or a base is added to it. In this case, the lake water contains substances that can react with the acid rain and prevent a significant change in pH. These substances can be either acidic or basic, capable of neutralizing the acid from the rain and maintaining a relatively stable pH.

3) A)
The compound responsible for both the general acidity of normal rainwater and the acidity of much soil is carbon dioxide (CO2) dissolved in water. When carbon dioxide combines with water, it forms carbonic acid (H2CO3):

CO2 + H2O ⇌ H2CO3

The presence of carbonic acid contributes to the acidity of rainwater and soil.

B)
While pollution can increase the levels of carbon dioxide in the atmosphere, it is not solely responsible for its presence. Carbon dioxide is a natural component of the Earth's atmosphere and is released through various natural processes such as volcanic activity, respiration of living organisms, and decay of organic matter.

C)
The carbonic acid formed from dissolved carbon dioxide is relatively weak, and seawater has a high buffering capacity due to dissolved salts, primarily bicarbonate (HCO3-) and carbonate (CO32-) ions. These ions can react with carbonic acid to maintain the alkalinity of seawater and prevent significant acidification.

D)
If all carbon dioxide were to vanish from the atmosphere, it would not benefit humans. Carbon dioxide plays a vital role in maintaining the Earth's temperature through the greenhouse effect. Without it, the planet would become extremely cold, making it inhospitable for most life forms. However, excessive levels of carbon dioxide resulting from human activities, such as burning fossil fuels, can contribute to climate change and have negative consequences. Achieving a balance is crucial for the well-being of both humans and the environment.