Final answer:
To vaporize 5 grams of water, the heat energy needed is calculated by multiplying the heat of vaporization (2,250 J/g) by the mass (5 g) resulting in 11,250 J, which is equivalent to 11.25 kJ. The closest provided answer is D. 11.3 kJ.
Step-by-step explanation:
The student is asking how much heat energy in Kilojoules (KJ) is needed to convert 5 grams of liquid water to vapor/gas. Using the information provided, the heat of vaporization of water is about 2,250 J per gram. To find the total energy required, we multiply the heat of vaporization by the mass of the water:
Energy (J) = Heat of Vaporization (J/g) × Mass (g)
Energy (J) = 2,250 J/g × 5 g
Energy (J) = 11,250 J
To convert from Joules to Kilojoules, we divide by 1,000:
Energy (kJ) = Energy (J) / 1,000
Energy (kJ) = 11,250 J / 1,000
Energy (kJ) = 11.25 kJ
Therefore, the correct answer is D. 11.3 kJ, which is the closest answer to our calculation.