physics

Question. The specific heat capacity of ethanol is 2400 $\text{J}\cdot {\text{kg}}^{-1}\cdot {\text{K}}^{-1}$. A sample of ethanol is heated from 22 degrees Celsius to 56 degrees Celsius. If 25kJ of energy was used, calculate the mass of the sample. {We know $Q=mc\Delta T$, and we solve to get 0.31 kg.}

Question. A cube of ice has mass 80 g and is initially at temperature of -10 degrees Celsius. Calculate the amount of heat energy required to melt the ice cube. Melting point of ice is 0 degrees. Specific heat capacity of ice is 2.11 $\text{kJ}\cdot {\text{kg}}^{-1}\cdot {\text{K}}^{-1}$. Latent heat of fusion is 334 $\text{kJ}\cdot {\text{kg}}^{-1}$. {We know that $Q=mc\Delta T$ and $Q=mL$, so the energy needed to heat it to 0 degrees will be $mc\Delta T$, and the energy needed to melt it will be $mL$. The answer is equal to $mc\Delta T+mL=0.08\cdot 2110\cdot 10+0.08\cdot 334000=28408$ (joules).}