Answer:
19.8 %
Explanation:
V% = ( V of solute \ 100 ml of solution ) ×100% =
the volume of the solute in 100ml solition = 20 ml
42.9 ml of solute ----------215 ml solution
× ----------- 100 ml solution
42.6 × 100 ml ÷ 215 ml
= 19.8 ml of solute
the V% = (19.8 ÷ 100) ×100% = 19.8%
Answer : The amount of heat released, 45.89 KJ
Solution :
Process involved in the calculation of heat released :

Now we have to calculate the amount of heat released.
where,
Q = amount of heat released = ?
m = mass of water = 27 g
= specific heat of liquid water = 4.184 J/gk
= specific heat of solid water = 2.093 J/gk
= enthalpy change for fusion = 40.7 KJ/mole = 40700 J/mole
conversion :
Now put all the given values in the above expression, we get
(1 KJ = 1000 J)
Therefore, the amount of heat released, 45.89 KJ