The water is more dense than the needle so it can withstand the weight. It is the contraction of the water falling faster than the others forming a drop pattern or the water getting smaller so the top looked smaller.
Key concepts
Density
Mass
Volume
Concentration
Buoyancy
Water
To find AH°rxn, we use the following equation:
What we're going to do is to sum the enthalpy of the products and then substract with the enthalpy of the reactives:
As you can see, we need to multiply by the coefficients of the reaction.
Now, just replace the values of the table:
So the answer is -822.2kJ/mol.
For b:
Now, just replace the values of the table:
The answer for b is -1036kJ/mol.
Answer:

Explanation:
Comparing to the solution consisting a pH of 5 containing
of hydrogen ions, a solution having a pH of 6 consists of
of hydrogen ions. A solution having a pH of 7 too will have a pH of
.