You can see a physical change always but not always a chemical
Answer:

Explanation:
From the question we are told that:
Density of acetic acid 
Density of Water 
Generally the equation for Solution Density is mathematically given by




Answer:
the discovery will always need to be tested more where if you're investigating you should already be in a more controlled environment
ANSWER: Milk
Explanation: Take this chart from 1-6 are acids from 8-14 those are bases
Now bases are like cleaning products and stuff
While acids are like lemons and other stuff
If you look at milk level which is 6.5 It is an acid but its A lot closer to neutral Than Other acids