When two aqueous solutions are mixed together and the temperature of the solution decreases, the reaction is called an endothermic reaction with a positive enthalpy change. Endothermic reaction is when heat is absorbed by the reaction taking place. All endothermic reaction always have a positive enthalpy change.
Answer:
B - Law of Conservation of Mass
Explanation:
was the right answer for me
Find the [OH-] in the solution. The pH is 9.5, so the pOH is 14 - 9.5 = 4.5.
[OH-] = 10^-4.5 M
Now use the dilution equation to find the new [OH-] after the volume is reduced from 150 mL to 50 mL:
M1V1 = M2V2
M1 = 10^-4.5 M
V1 = 150 mL
M2 = ?
V2 = 50 mL
(10^-4.5)(150) = M2(50)
M2 = 9.5 x 10^-5 M ≈ 1 • 10^-4 (We can only use one sig fig, because the pH was given to one decimal place.)
Now use this [OH-] to find pOH:
pOH = -log(1 x 10^-4) = 4.0
14 - pOH = pH, so the expected pH for the new solution is 10.
Isotonic refers to a solution having the same water potential as compared to another solutions such that there is no net movement of water molecules across a membrane when these two solutions are put together
