A student investigates the energy needed to change ice at 0 degrees C into water at 0 degrees C. Fig. 1 shows crushed ice in a beaker placed in a warm water...
Question 1 Report
A student investigates the energy needed to change ice at 0 degrees C into water at 0 degrees C. Fig. 1 shows crushed ice in a beaker placed in a warm water bath. The student measures the mass of ice melted and calculates that 16 800 J is transferred to melt 0.050 kg of ice.
(a) State what happens to the temperature of the ice-water mixture while ice is melting. [1]
(b) Calculate the specific latent heat of fusion of the ice. [3]
(c) Explain why the transferred energy does not increase the temperature during melting. [3]
(d) State one method the student could use to reduce energy transferred from the water bath to the room. [2]
Answer Details
(a) While the ice melts, the temperature of the ice-water mixture remains constant at 0°C. [1]
(b) Specific latent heat is the energy needed to change the state of 1 kg of a substance without changing its temperature.
\[E=mL\]
\[L=\frac{E}{m}=\frac{16800}{0.050}=336000\text{ J kg}^{-1}\]
The specific latent heat of fusion is \(336000\text{ J kg}^{-1}\). [3]
(c) During melting, the transferred energy is used to overcome the forces, or bonds, between particles. The particles separate as the solid changes to a liquid. Their kinetic energy does not increase, so their temperature does not increase. [3]
(d) Use insulation or a lid around the water bath. This reduces energy transfer to the room, for example by convection or radiation. [2]
Download The App On Google Playstore
Everything you need to excel in your exams
