Becuase they have water and oxygen carbon dioxide in them
Answer:
C) 
Explanation:
pH is defined as the negative logarithm of the concentration of hydrogen ions.
Thus,
pH = - log [H⁺]
The expression of the pH of the calculation of weak acid is:-
Where, C is the concentration = 0.5 M
Given, pH = 2.94
Moles = 0.100 moles
Volume = 1.00 L
So, 
C = 0.100 M



The answer you are looking for is A: Adding more batteries will increase the current
Since you have a circuit in series, that means that all of the bulbs would be connected to one wire. If you were add more batteries to that <em>one </em>wire, you would end up with a greater flow of energy throughout the bulbs/wire
Calcium has only two valence electrons in its shell. In order to agree with the octet rule it bonds with oxygen which has 6 valence electrons and with hydrogen which has 1 valence electron. Hope this answers the question. Have a nice day.