The key equation to this question is the energy transfer equation of Q = mcT. Q represents the amount of energy put into the system, m is the mass of the object we're talking about in kg, c is its specific heat capacity, and T is the change in temperature of the object in degrees celsius. The specific heat capacity can be thought of as how much energy is required to increase 1kg of an object by 1 degree celsius. Now to solve this equation. We don't know the mass of the liquid but we can find it out by multiplying its volume by its density, and so then putting this and the other provided information into the equation we get: Q = (0.1*1)20004 = 800J. Notice how I used 2000 in this equation, not 2, as the specific heat capacity was given in terms of kJ and the answer was in J.