45) This question asks us to find the heat required to melt the ice. Firstly, it is important to realize that the block of ice is already at 0°C, which is the melting point of ice. So we just need to find the heat added during the phase change. During the phase change, the temperature of the substance remains constant, so we will use the following equation.
We are given both mass and latent heat, so we can solve this equation easily. This problem only gives one value of latent heat, so it is obvious which one we need to use, but some problems may give two values and it is important to differentiate them. Latent heat of fusion is used for solid-liquid phase changes. Latent heat of vaporization, however, is used for liquid-gas phase changes. Our substance is going through a solid-liquid(ice to water) phase change, so we can use latent heat of fusion.
Answer: E
Comments