Answer: 1.36 M
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

where,
n = moles of solute
To calculate the moles, we use the equation:
moles of solute= 

The balanced reaction between barium hydroxide and perchloric acid:

To calculate the concentration of acid, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is 
We are given:

Putting values in above equation, we get:

Thus the concentration of the acid is 1.36 M
C. Melting ice.
It is C because melting ice is a change of state from solid to liquid which requires an addition of energy(or entropy) into the system.
Condensation of water occurs from a gas to a liquid state, which takes energy out of the system(water) and gives it to the surroundings(air around it). Freezing water is the same as condensation except for the state change. Deposition is simply gas to a solid instantaneously so you can again see it as with the other two examples.
They are organized into crystals hope i helped
Answer: The answer is C. The reaction system absorbs 22 kJ of energy from the surroundings.
Explanation: I just took the quiz and it said I got it right.