The pH value can be measured using electrochemical measuring systems, litmus paper, or indicators and colorimeters. The easiest way to take a pH measurement is to use litmus paper or a colorimeter. The advantage of this type of pH measurement is that the pH range is well known and they are easy to apply.
Answer: Bubbles formed would be evidence that a chemical reaction took place when the solutions were combined.
Explanation:
As it is given that both 
and HCl chemically combine together leading to the formation of NaCl, water and carbon dioxide gas. As the gas is forming and its formation will also form bubbles into the solution.
This formation of bubbles actually indicate that a chemical reaction has taken place. As molecules of a gas are held by Vander waal forces so, this gas will readily escape into the atmosphere.
Thus, we can conclude that bubbles formed would be evidence that a chemical reaction took place when the solutions were combined.
Answer:
Explanation:
The river bank can expand due to the water breaking apart and move for sediment.
You would use the formula for Boyle's Law:
(P1) (V1) = (P2) (V2)
(101.5) (2.0) = (P2?) (.75)
*P2 = 270kPa (You're allowed 2 significant figures)
P = Pressure
V = Volume
I think the family of Group 2 metals are most likely to form a 2+ion.
