Which of the following quantities is NOT required to calculate the amount of heat energy required?

e) the heat of vaporization for water why? Because most all heat energy experiments are conducted in a closed system. The water can not evaporate so that variable is not needed.

The variables you need are the specific heat of water, the mass of the water, and the change in temperature. Multiply all those together and you will get the heat energy. The unit will be based on the unit of specific heat, mass, etc. So the answer is e.

Water at a pressure of 16kPa (high vacuum) will boil at 55°C. You will therefore need all of the above in this instance. (Working with High Vac. Surface Condensers for 40,000 HP. Condensing Steam Turbines under the above operating conditions). At normal STP conditions, the Latent Heat of Vaporisation will not be required as you're not vaporising the water. However again. The water at any temperature is always Evaporating. As temperature increases, evaporation rate also increases. If the mass of water is measured at 25°C and again at 55°C, it will have decreased. The Heat of Vaporisation will therefore account for the loss of mass.

(e)... water at 25 C is a liquid.. it is also a liquid at 55 C.... we know this because the freezing point is 0C and the boiling point is 100C... as a liquid, the amount of heat added = Q = m Cp dT Q is heat m = mass Cp = heat capacity of liquid water dT = change in temperature = temp final - temp initial (a), (b), (c) and (d) are in the equation Q = m Cp dT

(e) is the answer. Its clear from this eqn. q = m x s x (delta)T where: q= heat energy req m = mass s = sp heat of the system (water here) delta T = change in temperature( final -initial)

e)the heat of vaporization for water because heat of water is from 25 C to 55C.