Answer:
This is an example of chemical change because the Kool aid dissolved and turned the water red
Answer: 127.5ml
Explanation:
To calculate the volume of acid, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is KOH.
We are given:

Putting values in above equation, we get:

Thus 127.5 ml of 0.5M of HNO3 would be needed to react with 85ml of 0.75M of KOH
Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.
Answer:
B. pOH = 14 - pH and D. pH = 14 - pOH.
Explanation:
Hello,
In this case, we must remember that pH and pOH are referred to a measure of acidity and basicity respectively, since pH accounts for the concentration of H⁺ and pOH for the concentration of OH⁻ in a solution. In such a way, since the maximum scale is 14, we say that the addition between the pH and pOH must be 14:

Therefore, the correct answers are B. pOH = 14 - pH and D. pH = 14 - pOH since the both of them are derived from the previous definition.
Best regards.
When water is in liquid form its molecules are free to move around.
Water molecules are packed reasonably close together. However when water freezes its molecules take up a hexagonal lattice (repeating structure) which has space in the middle of it.
This is largely due to hydrogen bonding between water molecules (complicated).
As a result water molecules in ice aren't packed as closely together as they are in liquid water so the density of ice is lower than that of liquid water.
Hope that helps. I doubt you need to know about hydrogen bonding.