How much heat is required to melt 50 g of mercury at -45 degrees celsius to 425 degrees celsius. (melting point=-38.degree-c, specific heat=0.03325 cal/g-degree c for solid mercury, .2988 cal/g-c degree c for liquid mercury and .2486 cal/g-c degree for gaseous mercury, heat of fusion =2.7 cal/g, heat of vaporization=65 cal/g)
To calculate the amount of heat required to melt 50 g of mercury from -45 degrees Celsius to 425 degrees Celsius, we need to consider the energy required for the different phase changes.
1. Heating the solid mercury from -45°C to its melting point at -38°C:
To calculate the heat required to raise the temperature of the solid mercury, we use the formula: Q = m * c * ΔT, where Q is the heat energy, m is the mass, c is the specific heat, and ΔT is the change in temperature.
Q1 = 50 g * 0.03325 cal/g-°C * (−38°C - (−45°C))
Q1 = 50 g * 0.03325 cal/g-°C * 7°C
2. Melting the solid mercury at its melting point of -38°C:
The heat required for this phase change is given by the heat of fusion formula: Q = m * ΔHf, where ΔHf is the heat of fusion.
Q2 = 50 g * 2.7 cal/g
3. Heating the liquid mercury from its melting point at -38°C to 425°C:
To calculate the heat required to raise the temperature of the liquid mercury, we again use the formula: Q = m * c * ΔT.
Q3 = 50 g * 0.2988 cal/g-°C * (425°C - (−38°C))
Q3 = 50 g * 0.2988 cal/g-°C * 463°C
Therefore, the total heat required to melt 50 g of mercury from -45°C to 425°C is the sum of Q1, Q2, and Q3:
Total heat = Q1 + Q2 + Q3
Calculate the values of Q1, Q2, and Q3 using the given data, and then sum them up to obtain the total heat required.