Calculate the energy needed to change 12g of ice at -20°c to liquid water at 0°c.

504 J.

Explanation:

Q = m.c.ΔT,

where, Q is the amount of heat absorbed by ice (Q = ??? J).

m is the mass of the ice (m = 12.0 g).

c is the specific heat of the ice (c of steam = 2.1 J/g.°C).

ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = 0.0°C - (-20.0°C) = 20.0°C).

∴ Q = m.c.ΔT = (12.0 g)(2.1 J/g.°C)(20.0°C) = 504 J.

Explanation:

The given data is as follows.

        = 25.0 ml,       = (10.0 ml + 25.0 ml) = 35.0 ml

        = 6.50 M,        

Relation between volume and molarity of the two liquids is as follows.

        =

        =    

              = 4.64 M

Thus, we can conclude that new concentration is 4.64 M.